1.Behavior of cartilage-derived microtissue and ability of cartilage formation in three-dimensional dynamic and static culture conditions
Wei LIU ; Hongyu JIANG ; Jiajie CHEN ; Yuyang GAO ; Yanjun GUAN ; Zhibo JIA ; Ying JIAO ; Zhen HUA ; Gehan JIANG ; Ying HE ; Aiyuan WANG ; Jiang PENG ; Jianhong QI
Chinese Journal of Tissue Engineering Research 2024;28(25):4022-4026
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.
2.In vitro construction of cartilage organoids based on extracellular matrix microcarriers of cartilage
Hongyu JIANG ; Wei LIU ; Jiajie CHEN ; Yanjun GUAN ; Zhibo JIA ; Yuyang GAO ; Wei FAN ; Aiyuan WANG ; Jiang PENG ; Yunkang YANG
Chinese Journal of Trauma 2024;40(1):29-39
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.
3.Expert consensus on the diagnosis and treatment of osteoporotic proximal humeral fracture with integrated traditional Chinese and Western medicine (version 2024)
Xiao CHEN ; Hao ZHANG ; Man WANG ; Guangchao WANG ; Jin CUI ; Wencai ZHANG ; Fengjin ZHOU ; Qiang YANG ; Guohui LIU ; Zhongmin SHI ; Lili YANG ; Zhiwei WANG ; Guixin SUN ; Biao CHENG ; Ming CAI ; Haodong LIN ; Hongxing SHEN ; Hao SHEN ; Yunfei ZHANG ; Fuxin WEI ; Feng NIU ; Chao FANG ; Huiwen CHEN ; Shaojun SONG ; Yong WANG ; Jun LIN ; Yuhai MA ; Wei CHEN ; Nan CHEN ; Zhiyong HOU ; Xin WANG ; Aiyuan WANG ; Zhen GENG ; Kainan LI ; Dongliang WANG ; Fanfu FANG ; Jiacan SU
Chinese Journal of Trauma 2024;40(3):193-205
Osteoporotic proximal humeral fracture (OPHF) is one of the common osteoporotic fractures in the aged, with an incidence only lower than vertebral compression fracture, hip fracture, and distal radius fracture. OPHF, secondary to osteoporosis and characterized by poor bone quality, comminuted fracture pattern, slow healing, and severely impaired shoulder joint function, poses a big challenge to the current clinical diagnosis and treatment. In the field of diagnosis, treatment, and rehabilitation of OPHF, traditional Chinese and Western medicine have accumulated rich experience and evidence from evidence-based medicine and achieved favorable outcomes. However, there is still a lack of guidance from a relevant consensus as to how to integrate the advantages of the two medical systems and achieve the integrated diagnosis and treatment. To promote the diagnosis and treatment of OPHF with integrated traditional Chinese and Western medicine, relevant experts from Orthopedic Expert Committee of Geriatric Branch of Chinese Association of Gerontology and Geriatrics, Youth Osteoporosis Group of Orthopedic Branch of Chinese Medical Association, Osteoporosis Group of Orthopedic Surgeon Branch of Chinese Medical Doctor Association, and Osteoporosis Committee of Shanghai Association of Integrated Traditional Chinese and Western Medicine have been organized to formulate Expert consensus on the diagnosis and treatment of osteoporotic proximal humeral fracture with integrated traditional Chinese and Western medicine ( version 2024) by searching related literatures and based on the evidences from evidence-based medicine. This consensus consists of 13 recommendations about the diagnosis, treatment and rehabilitation of OPHF with integrated traditional Chinese medicine and Western medicine, aimed at standardizing, systematizing, and personalizing the diagnosis and treatment of OPHF with integrated traditional Chinse and Western medicine to improve the patients ′ function.
4.Progress of Clinical Studies on the Use of Sodium Valproate in Adult Patients with Epilepsy Combined with Nonalcoholic Fatty Liver Disease
Zheng YIN ; Pei LI ; Kejing LI ; Aiyuan WANG ; Qianqian JI
Herald of Medicine 2024;43(9):1429-1434
Epilepsy patients are prone to obesity and metabolic syndrome(MetS),which is a higher risk than the general population.Nonalcoholic fatty liver disease(NAFLD)is a manifestation of a metabolic syndrome,characterized by hepatic steatosis,which can be exacerbated to some extent in patients with epilepsy.Sodium valproate(VPA),a commonly used clinical antiepileptic drug,leads to triglyceride accumulation in liver cells and induces a risk of NAFLD.In adults with epilepsy combined with NAFLD,treatment with VPA can make the liver,which is already affected by steatosis,more sensitive to VPA-induced liver injury and affect VPA drug metabolism.Both VPA and NAFLD induce hepatic steatosis,and can exacerbate each other's induced hepatic steatosis synergistically during epilepsy treatment.In this paper,we reviewed the progress of clinical studies on the use of VPA in adult patients with epilepsy combined with NAFLD to provide references for effective treatment and future studies of VPA.
5.Correlation analysis between arch index and foot kinematic parameters and their characteristics in stress fracture of lower extremity
Yong FENG ; Yanxu ZHAO ; Hongbin DONG ; Hao ZHOU ; Longze ZONG ; Yiqun WAN ; Jiang PENG ; Peifu TANG ; Minze ZHANG ; Aiyuan WANG
Chinese Journal of Trauma 2022;38(9):828-833
Objective:To analyze the relationship between arch index and foot kinematic parameters and their characteristics in stress fracture of lower extremity.Methods:A case-control study was performed for 108 recruits selected from a certain army unit in 2019. Before training, the recruits′ foot print images were collected by the capacitive plantar pressure measurement system to calculate their arch indices. The kinematic characteristics of the foot were analyzed by the dynamic gait posture analysis system. Spearman rank correlation analysis between arch index and foot kinematic parameters including landing elevation angle, toe-off angle, landing speed, landing varus angle, valgus amplitude and landing valgus speed were performed. Throughout the training, orthopedic physicians followed up the recruits, among whom 10 were excluded due to other types of lower extremity injuries. The arch index and foot kinematic characteristics were analyzed and compared between the remained recruits with stress fracture of lower extremity (fracture group, n=10) and those without lower extremity injury (control group, n=79). Results:(1) For the recruits, the arch index was 0.21(0.12,0.25), with landing elevation angle for (17.31±4.02)°, toe-off angle for (63.90±5.63)°, landing speed for (176.85±24.39)°/s, landing varus angle for (13.64±4.44)°, valgus amplitude for (12.16±3.42)°, and landing valgus speed for 382.50(311.05,474.80)°/s. (2) The landing varus angle ( r=0.25, P<0.01) and valgus amplitude ( r=0.14, P<0.05) were positively related to the arch index. (3) The arch index, toe-off angle and landing valgus speed were 0.20(0.07,0.24), (61.59±5.51)° and 336.00(251.02,428.67)°/s in fracture group, significantly lower than 0.23(0.17,0.26), (64.79±4.79)° and 381.20(313.63,470.92)°/s in control group ( P<0.05 or 0.01). There were no significant differences in the landing elevation angle, landing speed, landing varus angle and valgus amplitude between the two groups (all P>0.05). Conclusions:The change of the arch index can affect the landing varus angle and valgus amplitude of the foot. Recruits who suffer from stress fracture of lower extremity have the characteristics of higher arch, lower toe-off angle and lower landing valgus speed.
6.Effects of bone-resorptive lesion on stress distribution of the femoral head and on progression in patients with osteonecrosis of the femoral head
Guangbo LIU ; Yuqian MEI ; Haiyang MA ; Qiang LU ; Haoye MENG ; Qi QUAN ; Yuxuan ZHANG ; Jun ZHAO ; Huo LI ; Aiyuan WANG ; Haili XIN ; Duanduan CHEN ; Shibi LU ; Jiang PENG
Chinese Journal of Orthopaedics 2020;40(7):408-416
Objective:To investigate effects of bone-resorptive lesion on stress distribution of femoral head and on progression in patients with osteonecrosis of the femoral head (ONFH).Methods:From April 2014 to September 2018, a total of 155 femoral heads from 94 patients diagnosed with ARCO stage II and III ONFH were retrospectively reviewed, including 77 males and 17 females with aged 39.90±10.45 years old (ranged from 18-64 years). The hips were divided into two groups according to whether there were bone-resorptive lesions. Further, we compared whether there was statistical difference between the two groups in staging. Then, a case of ARCO II hip joint without bone-resorptive lesion was selected from the included patients. Six femoral head with different diameters of spherical bone-resorptive lesion of 5 mm, 7 mm, 10 mm, 14 mm, 18 mm, and 23 mm were simulated. The influence of bone-resorptive lesion on the stress distribution of necrotic area and a spherical shell extending 1 mm radially around the bone-resorptive lesion was investigated by finite element method in slow walking conditions.Results:Of the 155 ONFH hips, 67 hips are complicated by bone-resorptive lesions, of which 17 were ARCO II, 50 were ARCO III. A total of 88 hips did not contain bone-resorptive lesions, of which 58 were ARCO II, ARCO III 30 cases. The proportion of ARCO stage II in the group with bone-resorptive lesions was significantly higher than that in the group without bone-resorptive lesions (χ 2=25.03, P=0.000). The finite element stress distribution cloud diagram showed that there was a stress concentration area around the bone-resorptive lesions. The maximum von Mises stress around bone-resorptive lesions in the models that contained a synthetic bone-resorptive lesions were significantly higher than those reported in the matched, non-synthetic bone-resorptive lesions finite element models ( t=3.139, P=0.026). The values for maximum von Mises stress around bone-resorptive lesions were 6.94±1.78 MPa and 5.01±0.35 MPa for the group with synthetic bone-resorptive lesions and the group non-synthetic bone-resorptive lesions, respectively. There was a positive correlation between the diameter of bone-resorptive lesions and the maximum and mean von Mises stress of necrotic areas as well as the maximum von Mises stress around bone-resorptive lesions. Conclusion:Bone-resorptive lesions can increase the maximum stress and average stress in the necrotic area. The larger the bone-resorptive lesion, the more the stress increases. There is a stress concentration area around the bone-resorptive lesions, which may accelerate the collapse of the femoral head.
7.Associated factors and pregnancy outcomes of trial of labor after cesarean: a prospective cohort study
Suhua WEI ; Xiaodong YE ; Lili QIU ; Yimin DAI ; Zhiqun WANG ; Jie LI ; Aiyuan YUE ; Feiran ZHANG ; Mingming ZHENG
Chinese Journal of Perinatal Medicine 2017;20(9):649-655
Objective To investigate the safety of trial of labor after cesarean (TOLAC) and clinical factors associated with successful TOLAC and to compare TOLAC with elective repeat caesarean section (ERCS) in terms of obstetric and neonatal outcomes.Methods A prospective cohort study was conducted among gravidas who had a history of lower segment cesarean section and were hospitalized in the Department of Obstetrics and Gynecology,the Affiliated Drum Tower Hospital of Medical School of Nanjing University from January to December 2014.Exclusion criteria included indications for caesarean section (such as placenta previa,placenta accreta,twin pregnancy,breech presentation and severe preeclampsia),serious maternal complications after cesarean section,lower uterine segment thinner than 3 mm and poor healing of uterine incision.Totally,287 gravidas were enrolled.Among them,142 chose TOLAC and the other 145 requested ERCS.Clinical data of those gravidas were collected and statistically analyzed by t-test,Log-rank test,Chi-square or Fisher's exact test.Results (1) The success rate of TOLAC was 90.8% (129/142).There was no significant difference in maternal age,gestational age,thickness of lower uterine segment,interval between the two deliveries and neonatal birth weight and asphyxia rate between the successful (n=129) and unsuccessful (n=13) groups (all P>0.05).Although the two groups had no significant difference in postpartum hemorrhage (PPH) rate,the gravidas who failed in TOLAC lost more blood than those who succeeded [425 (195-675) vs 200 (50-1 400) ml,P<0.05].Moreover,higher amniotic fluid contamination rate was observed in the unsuccessful group [6/13 vs 17.1% (22/129),P<0.05].In the TOLAC group,99.3% (141/142) were under continuous fetal heart rate monitoring.Incomplete uterine rupture occurred in one women without serious maternal or neonatal outcomes.The reasons for 13 failed TOLAC cases were unbearable pain during labor,abnormal labor,fetal distress and threatened rupture of uterus.(2) Compared with the ERCS group,the TOLAC group showed shorter interval from last cesarean section to the indexed delivery[5 (2-18) vs 6 (2-19) years],younger maternal age [(31±4) vs (33 ±4) years old] and less blood loss [200 (50-1 400) vs 300 (100-1 500) ml] (all P<0.05).Conclusion Our study shows that,those who preferred TOLAC were younger,or had shorter pregnancy interval from last cesarean section.The success rate of TOLAC is high for women undergoing systematic prenatal assessment and close management during labor with less blood loss and non-serious maternal and neonatal complications compared with ERCS.
8.Relationship Between Slow Coronary Flow and Coronary Microcirculatory Dysfunction in Relevant Patients
Peiming YIN ; Shuguang WANG ; Aiyuan ZHANG
Chinese Circulation Journal 2016;31(6):555-558
Objective: To study the relationship between slow coronary lfow (SCF) and coronary microcirculatory dysfunction in relevant patients and to explore the risk factors for SCF development. Methods: Our research was conducted in 2 groups: SCF group, the patients with coronary angiography conifrmed diagnosis and Control group, the subjects with normal coronary lfow.n=32 in each group. The general information, blood levels of biochemical indicators, hs-CRP levels, TIMI lfow frame and the index of microcirculatory resistance (IMR) were examined, their relationships to SCF were analyzed. Results: Compared with Control group, the patients in SCF group showed the lower levels of HLL-C (1.57 ± 0.38) mmol/L vs (1.62 ± 0.43) mmol/L and Apo-A1 (1.41 ± 0.31) mmol/L vs (1.57 ± 0.38) mmol/L, while higher level of hs-CRP (3.63 ± 1.67) μg/mL vs (1.74 ± 0.75) μg/mL; SCF groups had increased IMR (29.28 ± 7.68) vs (24.94 ± 6.67), all P<0.05. IMR was positively related to TIMI lfow frame (r=0.766, P=0.019) and hs-CRP (r=0.565, P=0.000). Conclusion:①Microcirculatory dysfunction was related to SCF.②Inlfammatory reaction, decreased blood levels of HDL-C and Apo-A1 might be involved in pathological process of SCF.
9.NEL-like type 1 gene transfection for prevention of traumatic femoral head necrosis in rats
Meng FAN ; Wenxue JIANG ; Aiyuan WANG ; Jiang PENG ; Li ZHANG ; Wenjing XU ; Shibi LU
Chinese Journal of Trauma 2016;32(8):748-753
Objective To determine the effect of NEL-like type 1 gene (NELL-1) transfection in vivo in the repair of traumatic femoral head necrosis.Methods Twenty-four SD rats were randomly divided into three groups (8 rats per group) according to the lottery method,ie,sham group (served as normal control),NELL-1 treatment group (injected NELL-1 gene by recombinant adenovirus vectors around the hip one week after osteonecrosis model induced surgically) and placebo group (given an equal volume of saline solution at the same time after the induction of osteonecrosis).Femurs were taken from the animals 5 weeks after surgery.Gross observation was performed for morphology changes,X-ray assessment for femoral head height and length ratio (H/L),Micro-CT measure for bone parameters of femoral head including total volume (TV),bone volume (BV),total mineralized content (TMC),trabecular thickness (Tb.Th) and trabecular space (Tb.SP),and histological study for osteocytes,osteoblasts and osteoclasts.Results Preserved femoral head shape was noted in NELL-1 treatment group compared to the obvious flattening of the femoral head in placebo group.No heterotopic osteogenesis was observed in any group.Femoral head H/L ratio for 0.753 2 ± 0.040 2 in NELL-1 treatment group was higher than 0.598 4 ± 0.037 0 in placebo group (P < 0.05),but lower than 0.920 2 ± 0.037 0 in sham group (P<0.05).TV,BV,TMC and BMD between NELL-1 treatment and sham groups did not differ significantly (P > 0.05),but all were increased compared to placebo group (P < 0.05).There was no significant differences in Tb.Th and Tb.SP among three groups (P > 0.05).Most osteocytes were alive in NELL-1 treatment group.More active osteoblasts and osteoclasts were noted in NELL-1 treatment group than those in placebo group.Conclusion NELL-1 gene transfection can preserve femoral head shape and bone content,promote osteoblast activity and neovascularization and hence is an effective treatment for rat traumatic osteonecrosis.However,the activity of osteoclasts is stimulated simultaneously.
10.Degradation of AZ31 magnesium alloysin vivo:micro-CT assessment
Yichi XU ; Heyong YIN ; Zhen SUN ; Haoye MENG ; Bo XIAO ; Aiyuan WANG ; Quanyi GUO ; Jiang PENG ; Shibi LU
Chinese Journal of Tissue Engineering Research 2016;20(16):2303-2309
BACKGROUND:Magnesium can be degraded voluntarily in vivo, so a second surgery is avoided. However, its aloys have not been widely used in the clinical orthopedics because there is a lack of accurate and reliable methods to assess its degradationin vivo.
OBJECTIVE:To explore the degradation of micro-arc-oxidized AZ31 magnesium aloy in the femoral condyle of rabbits based on micro-CT images and relative data.
METHODS:Forty micro-arc-oxidized AZ31 magnesium aloys were implanted into the right femoral condyle of 40 New Zealand rabbits. Then 10 right femoral condyles were removed at 5, 10, 15 and 20 weeks after surgery, respectively, to quantitatively analyze and evaluate the degradation of AZ31 magnesium aloys by micro-CT images and relative data.
RESULTS AND CONCLUSION:The surface of AZ31 aloys was corroded progressively with dark color and distorted appearance at 5-20 weeks post implantation. Micro-CT images showed that in the first 5 weeks, the degradation was inactive, and at the 10th week, it turned active; at the 15th week, the corrosion pits were obviously increased in number, and the corrosion area and corrosion speed were enlarged and fastened, respectively. Up to the 20th week, the aloy surfaces were ful of corrosion pits besides roughness and discontinuity. Relevant data analysis showed that the volume fraction of magnesium aloy was 98.6%, 97.1% and 86.4% at the 5th, 10th and 20th weeks after implantation, respectively, and it had a significant decrease from the 10th to 15th week and from the 15th to 20th week (P < 0.05). Within 15-20 weeks, the volume fraction of magnesium aloy was decreased by 6.5% that was the maximum volume reduction per unit cycle. With the progress of corrosion, the surface continuously became rough and vague, and its surface area was enlarged; the ratio of surface area to volume continuously increased, and there was a significant difference at 15 and 20 weeks (P < 0.05). Because of the increasing number of corrosion pits, the cross-sectional radius decreased, which was reflected by the trabecular thickness decreasing from 1.00 to 0.87 mm. From the view of the slope of curve, the trabecular thickness decreased most rapidly at 10-15 weeks. The mineral density of magnesium aloy continuously decreased from 649.302 to 356.445 mg/cm3 during the whole experiment period (P< 0.05). In addition, the micro-CT image density decreased from 679.710 to 644.947 mg/cm3, but there was no significant difference. To conclude, the degradation speed is peaked at 10-20 weeks after implantation, and the content of magnesium aloys decrease with degradation, but the magnesium density has no significant change.

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