BACKGROUND:Compared with traditional two-dimensional culture,three-dimensional microtissue culture can show greater advantages.However,more favorable cultivation methods in three-dimensional culture still need to be further explored. OBJECTIVE:To evaluate the cell behavior of microtissue and its ability to promote cartilage formation under two three-dimensional culture methods. METHODS:Cartilage-derived microcarriers were prepared by chemical decellularization and tissue crushing.DNA quantification and nuclear staining were used to verify the success of decellularization,and histological staining was used to observe the matrix retention before and after decellularization.The microcarriers were characterized by scanning electron microscopy and CCK-8 assay.Cartilage-derived microtissues were constructed by combining cartilage-derived microcarriers with human adipose mesenchymal stem cells through three-dimensional static culture and three-dimensional dynamic culture methods.The cell viability and chondrogenic ability of the two groups of microtissues were detected by scanning electron microscopy,live and dead staining,and RT-qPCR. RESULTS AND CONCLUSION:(1)Cartilage-derived microcarriers were successfully prepared.Compared with before decellularization,the DNA content significantly decreased after decellularization(P<0.001).Scanning electron microscope observation showed that the surface of the microcarrier was surrounded by collagen,maintaining the characteristics of the natural extracellular matrix of cartilage cells.CCK-8 assay indicated that microcarriers had no cytotoxicity and could promote cell proliferation.(2)Scanning electron microscopy and live and dead staining results showed that compared with the three-dimensional static group,the three-dimensional dynamic group had a more extended morphology of microtissue cells,and extensive connections between cells and cells,between cells and matrix,and between matrix.(3)The results of RT-qPCR showed that the expressions of SOX9,proteoglycan,and type Ⅱ collagen in microtissues of both groups were increased at 7 or 14 days.The relative expression levels of each gene in the three-dimensional dynamic group were significantly higher than those in the three-dimensional static group at 14 days(P<0.05).At 21 days,the three-dimensional static group had significantly higher gene expression compared with the three-diomensional dynamic group(P<0.001).(4)The results showed that compared with three-dimensional static culture microtissue,three-dimensional dynamic culture microtissue could achieve higher expression of chondrogen-related genes in a shorter time,showing better cell viability and chondrogenic ability.

Limb dismemberment injuries are common in clinical practice,and safe and effective protection of the dismembered limb is the key to successful limb replantation.Normothermic machine perfusion has made significant breakthrough in the field of organ transplantation,which may maintain the active function of organs and tissues for a long period of time and prolong the preservation time.These findings have been validated in large animal models and clinical trials.Meantime,this technology is expected to provide novel reference for the preservation and functional recovery of severed limbs.Therefore,this paper reviews the problems of static cold preservation in the preservation of disarticulated limbs,the development history of mechanical perfusion,the current status of clinical application of ambient mechanical perfusion of disarticulated limbs as well as the problems to be solved,and looks forward to the direction of its development and the prospect of its clinical application,with a view to promoting the wide application of this technology in the clinic.

Objective:To study the in vitro construction of functional and self-renewing cartilage organoids based on cartilage acellular extracellular matrix (ECM) microcarriers.Methods:Fresh porcine articular cartilage was taken. The merely crushed cartilage particles were set as natural cartilage group and ECM microcarriers of appropriate particle size, which were prepared by the acellular method of combining physical centrifugation and chemical extraction, were set as microcarrier group. Cartilage organoids were constructed by loading human umbilical cord mesenchymal stem cells (hUCMSCs) and human chondrocytes (hCho) with a ratio of 3∶1 with microcarriers through a rotating bioreactor. The organoids with different induction times were divided into 0-, 7-, 14-, and 21-day induction groups. The cell residues of the microcarrier group and natural cartilage group were evaluated by 4′, 6-diaminidine 2-phenylindole (DAPI) fluorescence staining and DNA quantitative analysis. The retention of microcarrier components was observed by Safranin O and toluidine blue stainnings, and the collagen and glycosaminoglycan (GAGs) levels in the microcarrier group and the natural cartilage group were determined by colorimetric method and dimethyl-methylene blue (DMMB) method. The microcarriers were further characterized by scanning electron microscopy and energy dispersive spectroscopy. The hUCMSCs cultured with Dulbecco′s Modified Eagle′s Medium (DMEM) supplemented with fetal bovine serum (FBS) in a volume fraction of 10% was used as the control group and the hUCMSCs cultured with the microcarrier extract was used as the experimental group. Subgroups of hUCMSCs cultured at 3 time points: 1, 3 and 5 days were set up in the two groups separately. Cell Counting Kit 8 (CCK-8) was used to detect the biocompatibility of the two groups. The cellular activity of the organoids of the 0-, 7-, 14-, and 21-day induction groups was detected by live/dead staining and the self-renewal ability of the cartilage organoids of the 14-day induced group was identified by Ki67 fluorescence staining. The organoids of the 7-, 14-, and 21-day induction groups were detected by RT-PCR in terms of the expression levels of chondrogenesis-related marker aggrecan (ACAN), type II collagen (COL2A1), SRY-related high mobility group-box gene-9 (SOX9), cartilage hypertrophy-and mineralization-related marker type I collagen (COL1A1), Runt-related transcription factor-2 (RUNX2), and osteocalcin (OCN). Colorimetric and DMMB assays were performed to determine the ability of organoids in the 0-, 7-, 14-, and 21-day induction groups to secrete collagen and GAGs.Results:The results of DAPI fluorescent staining showed that the natural cartilage group had a large number of nuclei while the microcarrier group hardly had any nuclei. The DNA content of the microcarrier group was (7.8±1.8)ng/mg, which was significantly lower than that of the natural cartilage group [(526.7±14.7)ng/mg] ( P<0.01). Saffranin O and toluidine blue staining showed that the microcarrier was dark- and uniform-colored and it kept a lot of cartilage ECM components. The collagen and GAGs contents of the microcarrier group were (252.9±1.4)μg/mg and (173.4±0.8)μg/mg, which were significantly lower than those of the natural cartilage group [(311.9±2.2)μg/mg and (241.3±0.7)μg/mg] ( P<0.01). Scanning electron microscopy showed that the surface of the microcarriers had uneven and interleaved collagen fiber network. The results of energy spectrum analysis showed that elements C, O and N were evenly distributed in the microcarriers, indicating that the composition of the microcarrier was uniform. The microcarrier had good biocompatibility and there was no statistical significance in the results of CCK-8 test between the control group and the experimental group after 1 and 3 days of culture ( P>0.05). After 5 days of culture, the A value of the experimental group was 0.53±0.02, which was better than that of the control group (0.44±0.03) ( P<0.05). In the 0-, 7-, 14-, and 21-day induction groups, hUCMSCs and hCho were attached to the surface of the microcarriers, with good cellular activity, and the live/death rates were (70.6±1.1)%, (80.5±0.6)%, (94.5±0.9)%, and (90.8±0.5)% respectively ( P<0.01). There were a large number of Ki67 positive cells in cartilage organoids. RT-PCR showed that the expression levels of ACAN, COL2A1, SOX9, COL1A1, RUNX2 and OCN were 1.00±0.09, 1.00±0.24, 1.00±0.18, 1.00±0.03, 1.00±0.06 and 1.00±0.13 respectively in the 7-day induction group; 4.16±0.28, 5.09±1.25, 5.65±1.05, 0.47±0.01, 1.68±0.02 and 0.21±0.06 respectively in the 14-day induction group; 13.42±0.92, 3.07±0.21, 1.84±1.08, 2.72±0.17, 2.91±0.18 and 3.32±1.20 respectively in the 21-day induction group. Compared with the 7-day induction group, the expression levels of ACAN, COL2A1, SOX9 and RUNX2 in the 14-day group were increased ( P<0.05), but COL1A1 expression level was decreased ( P<0.05), with no significant difference in OCN expression level ( P>0.05). Compared with the 7-day induction group, the expression levels of ACAN, COL1A1 and RUNX2 in the 21-day induction group were significantly increased ( P<0.01), with no significant differences in the expression levels of COL2A1, SOX9 and OCN ( P>0.05). Compared with the 14-day induction group, the expression levels of ACAN, COL1A1, RUNX2 and OCN in the 21-day group were increased ( P<0.05 or 0.01), with no significant difference in the expression level of COL2A1 ( P>0.05), but the expression level of SOX9 was decreased ( P<0.05). The contents of collagen in 0-, 7-, 14-and 21-day induction groups were (219.15±0.48)μg/mg, (264.07±1.58)μg/mg, (270.83±0.84)μg/mg and (280.01±0.48)μg/mg respectively. The GAGs contents were (171.18±1.09)μg/mg, (184.06±1.37)μg/mg, (241.08±0.84)μg/mg and (201.14±0.17)μg/mg respectively. Compared with the 0-day induction group, the contents of collagen and GAGs in 7-, 14-, and 21-day induction groups were significantly increased ( P<0.01), among which the content of collagen was the lowest in 7-day induction group ( P<0.01) but the highest in the 21-day induced group ( P<0.01); the content of GAGs was the lowest in the 7-day induced group ( P<0.01) but the highest in the 14-day induction group ( P<0.01). Conclusions:The microcarriers prepared by combining physical and chemical methods are decellularized successfully, with more matrix retention, uniform composition and on cytotoxicity. By loading microcarriers with hUCMSCs and hCho, cartilage organoids are successfully constructed in vitro, which are characterized by good cell activity, self-renewal ability, strong expression of genes related to chondrogenesis and secretion of collagen and GAGs. The cartilage organoids constructed at 14 days of induction have the best chondrogenic activity.

Objective To compare the positive rate ofthyroid autoantibodies in infertile women with different ovarian reserve function,and investigate the immune factors of diminished ovarian reserve.Methods A cross-sectional study was conducted on infertile women admitted to Department of Reproductive Medicine of Beijing Gynaecology and Obstetrics Hospital from June to December,2020.The levels of anti-Müllerian hormone (AMH ),thyroid stimulating hormone (TSH ),thyroglobulin antibody (TGAb ) and thyroid peroxidase antibody (TPOAb)were detected in the 526 enrolled infertile patients.According to their AMH level,they were divided into normal ovarian reserve group and diminished ovarian reserve group.After they were stratified according to their age,the differences of TSH,TGAb and TPOAb levels were compared in the different age groups to analyze the related factors for diminished ovarian reserve.Results Univariate analysis showed that the diminished ovarian reserve group had significantly higher positive rates of TPOAb (18.8％ vs 11.1％,P=0.024)and TGAb (18.8％ vs 8.0％,P=0.001 )than the normal ovarian reserve group.Multivariate logistic regression analysis indicated that age and TGAb positivity were related to diminished ovarian reserve[OR=1.083(95％ CI:1.021～1.150),P=0.008;OR=1.159(95％ CI:1.034～1.301 ),P=0.011].Subgroup analysis suggested that the positive TGAb and TPOAb were significantly correlated with AMH level in the 36-～40-year-old group (P<0.05).Conclusion The infertile women with diminished ovarian reserve have higher TGAb and TPOAb levels,and the diminishment in those aged 36～40 years might be related to the positive TGAb and TPOAb.

Objective To observe the effect of Qixian Tongluo Formula on contralateral corticospinal tract(CST)remodeling and motor functional recovery in rats with cerebral infarction,and to explore its potential molecular mechanism from the perspective of regulating factors related to never remodeling.Methods The rat middle cerebral artery occlusion(MCAO)model was established by silk thread ligation.Fifty model rats were randomly divided into model group,citicoline group(0.054 g·kg-1),Qixian Tongluo Formula low-,medium-and high-dose(7.83,15.66,31.32 g·kg-1)groups,and sham operation group,with 10 rats in each group.The intervention administration was started on the 3rd day after operation once a day for 26 consecutive days.On the 3rd,14th and 28th day after operation,the gross motor function was evaluated by Longa score,and the fine motor function was evaluated by beam-walking test(BWT)score.The contralateral motor cortex was injected with the nerve tracer biotin dextran amine(BDA)on the 14 th day after operation to anterogradely trace the CST.On the 28th day after operation,the expression of axonal growth associated protein-43(GAP-43)and BDA positive fibers in the contralateral motor cortex and cervical spinal cord were detected by immunohistochemistry.The co-localization areas of BDA positive fibers and presynaptic marker protein vesicular glutamate transporter 1(VGLUT1)in the cervical spinal cord gray matter were detected by immunofluorescence.The expressions of brain-derived neurotrophic factor(BDNF),glial cell-derived neurotrophic factor(GDNF),nerve growth factor(NGF)and nerve remodeling-associated inhibitory factor[Nogo-A,oligodendrocyte myelin glycoprotein(OMgp)and myelin-associated glycoprotein(MAG)]in the contralateral motor cortex were detected by Western Blot.Pearson correlation analysis was used to analyze the correlation between Longa score or BWT score and BDA/VGLUT1 co-localization area,respectively.Results Compared with the sham operation group,rats in the model group had obvious symptoms of motor function deficits,and the Longa scores were significantly increased(P＜0.01)and the BWT scores were significantly decreased(P＜0.05,P＜0.01)at each time point.The expression of GAP-43 in the contralateral motor cortex and cervical spinal cord was up-regulated(P＜0.05),the number of edge-crossing fibers from the posterior funiculus in cervical cord was increased(P＜0.05),the co-localization area of BDA/VGLUT1 in the gray matter of the cervical spinal cord was increased(P＜0.05),the expressions of BDNF,GDNF and NGF in the contralateral motor cortex were up-regulated(P＜0.05),while the expressions of Nogo-A,OMgp and MAG were down-regulated(P＜0.05).Compared with the model group,the Longa scores in each administration group on the 14th and 28th day after MCAO operation were significantly decreased(P＜0.01),the BWT scores were significantly increased(P＜0.01),the expression of GAP-43 in the contralateral motor cortex and cervical spinal cord was significantly up-regulated(P＜0.01).The number of edge-crossing fibers from the posterior funiculus in cervical cord was significantly increased(P＜0.01),the co-localization area of BDA/VGLUT1 in the gray matter of the cervical spinal cord was significantly increased(P＜0.01).The expressions of BDNF,GDNF and NGF in the contralateral motor cortex were significantly up-regulated(P＜0.01,P＜0.05),while the expressions of Nogo-A,OMgp and MAG were significantly down-regulated(P＜0.05),and the most significant effect was observed in the high dose group.The Longa score was negatively correlated with the co-localization area of BDA/VGLUT1(r=-0.89,P＜0.01),and the BWT score was positively correlated with the co-localization area of BDA/VGLUT1(r=0.84,P＜0.01).Conclusion Qixian Tongluo Formula can improve motor function through promoting contralateral CST remodeling in MCAO rats after cerebral infarction,and the molecular mechanism may be related to the regulation of the expression of nerve remodeling-associated factor in the contralateral motor cortex.

【Objective】 To analyze the basic characteristics of whole blood donors from blood stations before and after the outbreak of COVID-19. 【Methods】 After excluding invalid data, data related to the basic characteristics of whole blood donors collected from 26 blood stations in China during 2018 to 2021 were statistically analyzed, including the trend of total whole blood donors, the number of repeated blood donors, the frequency of blood donation, the average age of donors and the recruitment of first-time blood donors. 【Results】 Affected by the epidemic, 8 out of 14 indicators were with large variations, accounting for 57%. The overall growth rate of total whole blood donors during the epidemic was higher than before the epidemic (P<0.05).The number of repeated blood donors has shown an increased trend, with a higher number during the epidemic than before (P<0.05). The frequency of blood donation was lower during the epidemic than before(P<0.05).Average ages of blood donors and female blood donors fluctuated widely during the epidemic, both higher than those before the epidemic(P<0.05).The donation rate of first-time blood donors <25 years old and ≥25 years old varied widely and irregularly during the epidemic (both P<0.05). The percentage of first-time blood donors fluctuated irregularly during the epidemic, with overall percentage lower than that before the epidemic(P<0.05). 【Conclusion】 Whole blood donors from 26 blood stations increased after the outbreak of COVID-19, and some indicators in certain areas showed significant fluctuations during the epidemic.

OBJECTIVE To study the effects of Dianxianqing granules on the tau protein in P301S mice by regulating mitophagy. METHODS Totally 36 P301S mice were randomly divided into model group， Dianxianqing granule group （12.48 g/kg）， donepezil hydrochloride group （positive control， 1.3 mg/kg）， with 12 mice in each group； another 10 C57BL6 mice were selected as control group. Administration groups were given relevant drug solutions intragastrically， and control group and model group were given constant volume of water intragastrically. The gavage volume was 20 mL/kg， once a day， for consecutive 5 months. During the experiment， the general condition of mice was observed in each group. After the last medication， the learning and memory ability was determined by Y maze test and Morris water maze test； HE staining was used to observe the morphological changes in brain tissue， and Nissl staining was used to observe the structure of neural cells and the number of Nissl bodies in cerebral tissue. Immunohistochemistry was used to detect the expressions of phospho-tau serine 202/threonine 205 （abbreviated as AT8） in brain tissue. Western blot assay was used to determine the expressions of mitophagy-associated proteins [PTEN-induced putative kinase-1 （PINK1）， Parkin， microtubule-associated protein 1 light chain 3B （LC3B）， p62]， synaptic-associated proteins [postsynaptic density protein-95 （PSD-95）， synaptophysin （SYP）， and growth-associated protein-43 （GAP-43）] and the phosphorylation of tau protein [expressed by the phosphorylation levels of serine 199 （Ser199） and Ser202] in brain tissue. RESULTS The mice in E-mail：lnzyxyqy2003@163.com model group showed symptoms such as white hair， decreased body mass， and lower limb paralysis， with incomplete hippocampal structures in their brain tissue， as well as incomplete cell membrane edges and cell structures； the spontaneous alternating response rate， the times of crossing platform， the number of Nissl bodies， the protein expressions of PINK1， Parkin， LC3B， SYP， GAP-43， and PSD-95 were decreased significantly， compared with control group； swimming latency （fourth and fifth day）， the protein expressions of AT8 and p62，the phosphorylation levels of Ser199 and Ser202 were increased or lengthened significantly， compared with control group （P＜0.05 or P＜0.01）. Compared with model group， the above symptoms and indexes of mice were improved significantly in administration groups （P＜0.05 or P＜0.01）. CONCLUSIONS Dianxianqing granules can effectively improve cognitive impairment in P301S mice，the mechanism of which may be associated with inducing mitochondrial autophagy， reducing the hyperphosphorylation of tau protein， up-regulating the expression of synaptic-associated proteins in brain tissue，and repairing damaged neural cells.

Objective:To study the current status of research in the field of iodine nutrition for pregnant women and to detect the hot spots and future trends in the field of iodine nutrition for pregnant women.Methods:Using "pregnant women" and "iodine" as search terms, we searched the literature related to iodine nutrition in pregnant women from January 2000 to December 2021 in China Knowledge Network (CNKI) database, Wanfang database and Chinese Medical Journal Full Text Database. CiteSpace 6.2.2.0 software was used to sort out the publication status, core authors and research hotspots of the papers.Results:A total of 879 valid papers were included, with an overall number of publications increasing trend from 2000 - 2021 and a decline after 2017. Among the 879 papers, 29 first authors were core authors (M≈3), and 109 papers were published, accounting for 12.40% of the total literature; several research groups with relatively stable collaborative relationships had been formed, with the larger collaborative team of Chen Zupei and Zhang Wanqi at Tianjin Medical University. Keyword co-occurrence analysis showed that pregnant women, urinary iodine, and iodine nutrition were high-frequency keywords; keywords with mediated centrality > 0.07 were pregnant women (0.48), pregnancy (0.40), urinary iodine (0.37), iodine deficiency disorders (0.25), iodine nutrition (0.20), thyroid (0.12), thyroxine (0.10), infants and children (0.09). The analysis of the emergent words showed that the evolution of iodine nutrition research themes in pregnant women was broadly based on studies of iodine nutrition monitoring results in key populations such as newborns and infants from 2000 - 2011, studies such as the range of thyroxine reference values during pregnancy from 2012 - 2016, and changes in iodine nutrition status of pregnant women and children after adjustment of iodized salt concentration from 2017 - 2021. The clustering results showed that a total of 355 keywords were aggregated to yield 10 clusters, and the average profile value of clusters (Silhouette) > 0.8, which was a reasonable clustering result; the study topics can be divided into three major categories, iodine nutrition and goiter monitoring results in key populations, thyroid hormones and pregnancy outcomes during pregnancy, and studies on thyroid-related diseases.Conclusions:Iodine plays an important role in the health of pregnant women and their offspring, and changes in the iodine nutrition status of pregnant women should be closely monitored. In response to the new trends of change that are currently present, multidisciplinary cooperation should be developed to respond to social concerns and jointly promote the maintenance of iodine nutrition in pregnant women at appropriate levels.

Objective:To investigate the protective effect of hypothermic antegrade machine perfusion against canine ischemic brain injury.Methods:Thirteen beagle dogs were divided into the mild hypothermia with perfusion group ( n=6) and normothermia with perfusion group ( n=7) according to the random number table. The model of ischemic brain injury was established by neck transection. After 1 hour of ischemic circulatory arrest, the perfusion fluid based on autologous blood was continuously perfused through bilateral common carotid artery for 6 hours. The temperature of the perfusion fluid was set at 33 ℃ in the mild hypothermia with perfusion group and 37℃ in the normothermia with perfusion group, respectively. Blood oxygen saturation was recorded at 0, 1, 2, 3, 4, 5 and 6 hours after the beginning of perfusion to evaluate the perfusate oxygen level. The perfusate was collected, and the levels of Na +, K +, Ca 2+ and glucose as well as the pH value of the perfusate were detected in the two groups. At the end of perfusion, the parietal brain tissues of 1 dog from each group were collected to evaluate the water contents of brain tissues. Nissl staining was used to evaluate the morphological integrity of the pyramidal neurons in the frontal cortex and hippocampus. Neuronal nuclei antigen (NeuN) was used to evaluate the structural and morphological integrity of pyramidal neurons. Immunofluorescence glial fibrillary acidic protein (GFAP) and ionic calcium binding adaptor molecule 1 (Iba1) were used to evaluate the integrity and activity of astrocytes and microglia fragments. Results:At 0, 1, 2, 3, 4, 5 and 6 hours of perfusion, there was no significant difference in the blood oxygen saturation or Na + concentrations between the two groups (all P>0.05); the K + concentrations in the mild hypothermia with perfusion group were (4.57±0.12)mmol/L, (4.67±0.14)mmol/L, (4.27±0.12)mmol/L, (4.45±0.10)mmol/L, (6.60±0.15)mmol/L, (7.37±0.18)mmol/L and (9.03±0.16)mmol/L, respectively, which were significantly lower than those in the normothermia with perfusion group [(4.84±0.10)mmol/L, (5.31±0.13)mmol/L, (5.44±0.24)mmol/L, (5.70±0.18)mmol/L, (7.79±0.18)mmol/L, (10.44±0.40)mmol/L, (10.40±0.41)mmol/L] (all P<0.01). At 0, 1, 2 and 3 hours of perfusion, the Ca 2+ concentrations in the mild hypothermia with perfusion group were (0.72±0.15)mmol/L, (1.55±0.16)mmol/L, (1.62±0.15)mmol/L and (1.88±0.15)mmol/L, respectively, being significantly higher than those in the normothermia with perfusion group [(0.41±0.13)mmol/L, (0.99±0.12)mmol/L, (1.29±0.13)mmol/L, (1.57±0.11)mmol/L] (all P<0.01), and no significant differences were found at other time points (all P>0.05). At 0, 1 and 2 hours of perfusion, the glucose concentrations in the mild hypothermia with perfusion group were (5.75±0.19)mmol/L, (5.17±0.15)mmol/L and (4.72±0.15)mmol/L, respectively, being significantly higher than those in the normothermia with perfusion group [(5.30±0.22)mmol/L, (4.89±0.20)mmol/L, (4.30±0.17)mmol/L] (all P<0.01), with no significant differences found at other time points (all P>0.05). At 2, 3, 4, 5 and 6 hours of perfusion, the pH values of the mild hypothermia with perfusion group were 7.32±0.06, 7.25±0.02, 7.23±0.02, 7.24±0.02 and 7.24±0.02, respectively, being significantly higher than those in the normothermia with perfusion group (7.26±0.01, 7.21±0.01, 7.17±0.02, 7.15±0.02, 7.08±0.02) ( P<0.05 or 0.01), with no significant differences at other time points (all P>0.05). The water content of brain tissues in the mild hypothermia with perfusion group was (74.9±0.4)%, which was significantly lower than (79.9±0.9)% in the normothermia with perfusion group ( P<0.01). Nissl staining showed that the pyramidal neurons in prefrontal cortex and dentate gyrus had good integrity in the mild hypothermia with perfusion group. NeuN immunofluorescence staining showed that the morphology and structure of pyramidal neuron cells in the mild hypothermia with perfusion group were better with clearly visible axons than those in the normothermia with perfusion group, whereas the cytosol was full and swollen with scarce axons in the normothermia with perfusion group. GFAP and Iba1 immunofluorescence staining showed that more structurally intact glial cells, more abnormally active cells, thickener axons and better axon integrity in all directions were found in the mild hypothermia with perfusion group than those in the normothermia with perfusion group. Conclusion:Compared with normal temperature antegrade mechanical perfusion, the mild hypothermia antegrade mechanical perfusion can protect canine brain tissue and alleviate ischemic brain injury by maintaining stable energy and oxygen supply, balancing ion homeostasis and perfusion fluid pH value, reducing tissue edema, and maintaining low metabolism of pyramidal neurons, astrocytes and microglia.

To analyze whether the serum concentration of estradiol on the day of progesterone conversion could predict the pregnancy outcome of frozen-thawed embryo transfer in hormone replacement cycle. In this paper, a case-control study was conducted to retrospectively analyze the 230 cycles of hormone replacement therapy-frozen thawed embryo transfer(HRT-FET)conducted by the Department of Reproductive Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University from January 2018 to December 2020. The concentration of serum estradiol was between 139.5-3 941.0 pg/ml. According to the percentile of serum estradiol concentration on the day of endometrial transformation, patients were divided into three groups: control group (<25th percentile, n=58), high estradiol group (25th-75th percentile, n=112) and ultra-high estradiol group (>75th percentile, n=60). Comparing the basic characteristics and pregnancy outcome of the three groups, the main observation index was the live birth rate, and the secondary observation index was the clinical pregnancy rate. F test and Kruskal-Wallis ( H) test were used to compare the measurement data, and χ 2 test was used to compare the counting data. The results showed that there was no significant difference in age, anti-Müllerian hormone(AMH), antral follicle count(AFC), body mass index(BMI), years of infertility and the proportion of primary infertility among the three groups( F=2.375, H=5.479, H=5.374, F=1.391, H=4.779, χ2=1.969, P>0.05). FET cycle treatment: There was no significant difference in the concentration of progesterone (P) before transformation, the thickness of endometrium on the day of transformation, the proportion of single embryo transfer and blastocyst transfer among the three groups ( H=5.359, H=5.957, χ2=0.626, χ2=4.532, P>0.05). The days of estrogen administration before endometrial transformation in the three groups during the FET cycle were 13.0 (12.0, 14.0) days in the high estradiol group and 13.0 (12.0, 15.0) days in the ultra-high estradiol group, which were significantly longer than those in the control group 13.0(12.0, 13.3)days. The E2 concentration before intimal transformation in high estradiol group was 1 560.4 (1 170.2, 1 848.2) pg/ml, while that in ultra-high estradiol group was 2 420.9 (2 131.0, 2 849.2) pg/ml, which was significantly higher than that in control group 238.8 (206.9, 287.0) pg/ml. The pregnancy outcome of the three groups: the clinical pregnancy rate of the three groups was 37.9% in the control group, 51.8% in the high estradiol group and 40.0% in the ultra-high estradiol group, of which the high estradiol group had the highest clinical pregnancy rate, followed by the ultra-high estradiol group. But there was no significant difference among the three groups (χ2=3.853, P>0.05). The embryo implantation rate of the three groups was 19.3%, 25.0%, 32.8%, respectively, and the embryo implantation rate of the ultra-high estradiol group was the highest, but there was no significant difference among the three groups (χ2=5.544, P>0.05).The live birth rate of the three groups was 37.9%, 39.3%, 40.0%, respectively, and the difference was not statistically significant (χ2=0.05, P>0.05). A total of 14(13.5%) abortions occurred in 104 clinical pregnancies, all of which occurred in the high estradiol level group. Of the 104 clinical pregnancies, 24 (23.1%) had twin pregnancies, which occurred in the high estradiol level group (10 cases) and the ultra-high estradiol level group (14 cases). There were no twin pregnancies in the control group. Ectopic pregnancy occurred in 4 of 230 FET cycles (1.7%), 2 in control group and 2 in high estradiol group, and no ectopic pregnancy in ultra-high estradiol group.