ObjectiveThe biosynthetic pathways of benzylisoquinoline alkaloids（BIAs） in Nelumbo nucifera are of great theoretical and economic value. In this paper， N. nucifera O-methyltransferase（NnOMT） and N. nucifera N-methyltransferase（NnNMT） gene families were identified and analyzed by bioinformatics in order to facilitate the biosynthetic pathway of BIAs in N. nucifera. MethodBased on the whole genome of N. nucifera， UniPort and National Center for Biotechnology Information（NCBI） databases were used to identify the NnOMT and NnNMT gene families of N. nucifera， and analyze their physicochemical properties and subcellular localization， then TBtools， MEME， MEGA 11.0， FigTree 1.4.4 and other tools were used to analyze the phylogeny， sequence characteristics， gene structure， functional annotation and cis-acting elements of NnOMT and NnNMT genes identified in the previous stage. ResultA total of 61 NnOMT and NnNMT genes were identified in this paper， the number of amino acids encoded by these genes ranged from 168 aa to 580 aa， the isoelectric point ranged from 4.76 to 9.16， and the relative molecular weight ranged from 18 699.52 Da to 64 934.53 Da， most of which showed acidic and mostly hydrophilic proteins. There were 10 conserved motifs， Kyoto Encyclopedia of Genes and Genomes（KEGG） analysis enriched a total of 12 pathways， including metabolism， biosynthesis of phenylpropane and isoquinoline alkaloids， etc. And Visualization of Gene Ontology（GO） enrichment results showed that 61 NnOMT and NnNMT genes were annotated to 32 items， which included 16 molecular functions［such as reduced nicotinamide adenine dinucleotide（NADH） activity and exopeptidase activity］ and 16 biological processes（such as metabolic process of carbon tetrachloride， anaerobic carbon tetrachloride metabolic process and responses to exogenous biological stimuli）. There were a variety of cis-acting elements in the promoter regions of NnOMT and NnNMT genes， mainly promoter and enhancer regions element， light responsive element and methyl jasmonate responsive element. ConclusionIn this study， a comprehensive bioinformatics analysis of 61 NnOMT and NnNMT genes is carried out based on the genome data of N. nucifera， which lays a foundation for research on the gene structure and function of NnOMT and NnNMT gene families， and provides a reference for biosynthetic pathway elucidation of BIAs in N. nucifera.

Objective:To construct a double-layer bone-on-a-chip containing bone matrix, with which the process of osteoblast and osteoclast differentiation in vitro is stimulated, aiming to provide a new platform for the development of osteoporosis medications. Methods:Software WorkSoild was used to design the double-layer and double-channel bone-on-a-chip and the template was fabricated by photolithography. With polydimethylsiloxane (PDMS) as the raw material, the main body of the chip was prepared by mold fabrication. The inlets and outlets of the four channels of the culture room were separated with bovine cortex bones and sealed with liquid storage columns. In the chip verification experiment, chips were divided into osteogenic and osteoclastic induction groups and osteogenic and osteoclastic control groups. In the osteogenic and osteoclastic induction groups, precursor cells of mouse embryonic osteoblast, MC3T3-E1 and mouse macrophage RAW264.7 were inoculated on the chip separately. Osteogenic induction lasted 14 days and osteoclastic induction 7 days. MC3T3-E1 cells and RAW264.7 cells were not induced in the osteogenic and osteoclastic control groups. The following indicators were observed: (1) Appearance and sealing performance of the chip: After the chip was prepared, photos were taken to observe its appearance and sealing tests were conducted to observe its sealing performance. (2) Biocompatibility: At 3 days after MC3T3-E1 cells were inoculated onto the chip and cultured and at 1, 3 and 5 days after RAW264.7 cells were inoculated onto the chip and cultured, the cell survival was observed with calcein acetoxymethyl ester/propidium iodide (AM/PI) staining and Cell Counting Kit 8 (CCK-8). (3) Osteogenic differentiation: Alkaline phosphatase (ALP) staining and alizarin red staining were performed on the cells in the osteogenic induction group to observe the osteogenic induction. RNA was collected from the osteogenic induction group and the osteogenic control group, the expression of osteoblast marker Runt-related transcription factor 2 (RUNX2), osteocalcin (OCN) and type I collagen (COL1A1) was detected by real-time florescent quantitative PCR (qPCR), and the differentiation degree and osteogenic ability of osteoblasts were observed. (4) Osteoclast differentiation: tartrate-resistant acid phosphatase (TRAP) staining was performed on cells in the osteoclastic induction group to observe osteoclast differentiation. RNA was extracted from the osteoclastic induction group and the osteoclastic control group for qPCR of osteoclast differentiation-related genes, and the expression levels of the osteoclast marker gene TRAP, cathepsin K (CTSK) and dendritic cell specific transmembrane protein (DC-STAMP) were detected.Results:The double-layer bone-on-a-chip containing bone matrix was 3 cm×3 cm in size and transparent as a whole. The structure of the system on the chip system was compact and had no seepage. It was shown by calcein AM/PI staining that at 3 days after MC3T3-E1 cells and RAW264.7 cells were cultured, very few red fluorescent dead cells were found. CCK-8 test showed that within 5 days after being cultured, the cell viability was all above 90%, indicating that the biocompatibility of the chip was good and the cells could survive and proliferate normally. The results of ALP and alizarin red staining showed that MC3T3-E1 cells successfully differentiated into osteoblasts and produced calcified nodules in the osteogenic induction group at 14 days after the induction. The qPCR results showed that the relative expression level of RUNX2 in MC3T3-E1 cells in the osteogenic induction group was 4.98±0.74, which was significantly higher than that of the control group (0.99±0.03) ( P<0.01). The relative expression level of OCN in MC3T3-E1 cells was 7.98±0.76, which was significantly higher than that of the control group (1.00±0.06) ( P<0.01). The relative expression level of COL1A1 in MC3T3-E1 cells was 7.07±0.56, which was significantly higher than that of the control group (0.97±0.03) ( P<0.01). The TRAP staining results showed that the RAW264.7 cells in the osteoclastic induction group differentiated to giant multinucleated osteoclasts, and TRAP protein was expressed in large quantity in the osteoclasts. The results of qPCR showed that the relative expression level of TRAP in RAW264.7 cells in the osteoclastic induction group was 3.35±0.37, which was significantly higher than that of the control group (1.01±0.06) ( P<0.01). The relative expression level of CTSK in RAW264.7 cells was 3.46±0.79, which was significantly higher than that of the control group (1.01±0.05) ( P<0.01). The relative expression level of DC-STAMP in RAW264.7 cells was 1.92±0.12, which was significantly higher than that of the control group (0.98±0.08) ( P<0.01). Conclusions:The double-layer bone-on-a-chip containing bone matrix is compact in structure, can be cultured in vitro for a long time, has good biocompatibility and can be used for inducing osteogenic and osteoclast differentiation. Therefore, it is expected to provide a new research platform for exploring the mechanism of osteoporosis and medication screening.

Objective:To explore the characteristics of renal oxidative stress injuries in rats with high-voltage electric burns and the intervention effects of breviscapine.Methods:This study was an experimental study. One hundred and sixty 8-10-week-old male Sprague Dawley rats were divided into sham injury group, electric burn group, saline group, low breviscapine group, middle breviscapine group, and high breviscapine group, with 60 rats in each of the sham injury group and electric burn group, 10 rats in each of the other 4 groups, respectively. The rats in sham injury group and electric burn group were divided into 10 rats at each time point, including post injury hour (PIH) 0 (immediately), 8, 24, 48, and 72, and post injury week (PIW) 1. The rats in sham injury group were not conducted with electrical current to cause sham injury. The rats in the other 5 groups were caused high-voltage electric burns. The rats in sham injury group and electric burn group were not treated after injury. The rats in saline group, low breviscapine group, middle breviscapine group, and high breviscapine group were intraperitoneally injected with 5 mL/kg normal saline or 0.4, 1.6, and 4.0 g/L breviscapine, repeated every 24 h until PIH 72. After the model was successfully made, 14 rats died, including 1, 2, 2, and 1 rat (s) at PIH 24, 48, and 72 and PIW 1 in electric burn group, 4, 1, 2, and 1 rat (s) at PIH 72 in saline group, low breviscapine group, middle breviscapine group, and high breviscapine group, respectively. The kidney tissue collected from rats in the 6 groups was weighed and the kidney/body weight ratio was calculated. The left upper pole tissue of kidney was collected from each 4 rats in sham injury group, and in electric burn group at PIH 8, 24, 48, and 72 and PIW 1, and in saline group, low breviscapine group, middle breviscapine group, and high breviscapine group at PIH 72. The renal tubular and renal interstitial injury was evaluated by a semi-quantitative histological scoring system after hematoxylin-eosin staining. The inferior vena cava blood samples were collected from rats in the 6 groups to measure the serum creatinine levels via sarcosine oxidase method, and serum urea nitrogen levels via urease method. The right renal cortices were collected from rats in the 6 groups to measure the catalase (CAT) activity in the supernatant of renal tissue via molybdic acid method, and the levels of advanced oxidation protein product (AOPP) and Klotho protein in the supernatant of renal tissue via enzyme-linked immunosorbent assay.Results:At PIH 8, 48, and 72 and PIW 1, the kidney/body weight ratios of rats in electric burn group were significantly higher than those in sham injury group (with t values of -0.52, -3.75, -4.05, and -2.25, respectively, P<0.05). At PIH 72, compared with those in electric burn group, saline group, low breviscapine group, and middle breviscapine group, the kidney/body weight ratio of rats in high breviscapine group was significantly decreased (with P values all <0.05). Compared with those in sham injury group, the renal tubular and renal interstitial injury scores of rats in electric burn group at PIH 48 and 72 and PIW 1 were significantly increased ( P<0.05). Compared with those in electric burn group at PIH 8 and 24, the renal tubular and renal interstitial injury score of rats in electric burn group at PIW 1 was significantly increased (with P values all <0.05). At PIH 72, the renal tubular and renal interstitial injury scores of rats in the 5 groups of rats with electric burns were similar ( P>0.05). At PIH 8, 24, 48, and 72 and PIW 1, the levels of serum creatinine and serum urea nitrogen of rats in electric burn group were significantly higher than those in sham injury group (with Z values of -2.00, -2.37, -2.62, -2.67, -3.67, -2.34, -3.11, -3.43, -3.11, and -3.51, respectively, P<0.05). Compared with that in electric burn group at PIH 0, the levels of serum creatinine of rats in electric burn group at PIH 72 and PIW 1 were significantly increased ( P<0.05). Compared with that in electric burn group at PIH 8, the levels of serum creatinine of rats in electric burn group at PIH 72 and PIW 1 were significantly increased ( P<0.05). Compared with that in electric burn group at PIH 24, the level of serum creatinine of rats in electric burn group at PIW 1 was significantly increased ( P<0.05). At PIH 72, the levels of serum creatinine of rats in the 5 groups of rats with electric burns were similar ( P>0.05). Compared with that in electric burn group, the levels of serum urea nitrogen of rats in low breviscapine group, middle breviscapine group, and high breviscapine group were significantly decreased ( P<0.05). Compared with that in saline group, the levels of serum urea nitrogen in middle breviscapine group and high breviscapine group were significantly decreased ( P<0.05). At PIH 48 and 72 and PIW 1, the CAT activities in the supernatant of renal tissue of rats in electric burn group were significantly lower than those in sham injury group (with Z values of -2.22, -2.13, and -3.51, respectively, P<0.05). At PIH 8, 24, 48, and 72 and PIW 1, the levels of AOPP in the supernatant of renal tissue of rats in electric burn group were significantly higher than those in sham injury group (with Z values of -2.00, -3.15, -2.71, -2.04, and -2.33, respectively, P<0.05). At PIH 0-PIW 1, the levels of Klotho protein in the supernatant of renal tissue of rats in sham injury group and electric burn group were all similar ( P>0.05). Compared with that in electric burn group at PIH 0, the CAT activities in the supernatant of renal tissue of rats in electric burn group at PIH 72 and PIW 1 and the levels of Klotho protein in the supernatant of renal tissue of rats in electric burn group at PIH 48 and 72 and PIW 1 were significantly decreased ( P<0.05). Compared with that in electric burn group at PIH 8, the CAT activities in the supernatant of renal tissue of rats in electric burn group at PIH 72 and PIW 1 and the levels of Klotho protein in the supernatant of renal tissue of rats in electric burn group at PIH 48 and 72 and PIW 1 were significantly decreased ( P<0.05). Compared with that in electric burn group at PIH 24, the CAT activities in the supernatant of renal tissue of rats in electric burn group at PIH 72 and PIW 1 were significantly decreased ( P<0.05). Compared with that in electric burn group at PIH 48, the CAT activity in the supernatant of renal tissue of rats in electric burn group at PIW 1 was significantly decreased ( P<0.05). At PIH 72, the levels of Klotho protein in the supernatant of renal tissue of rats in the 5 groups of rats with electric burns were similar ( P<0.05). Compared with 14.6 (12.6, 23.6) U/mgprot in electric burn group, the CAT activities in the supernatant of renal tissue of rats in low breviscapine group (20.5 (18.0, 39.8) U/mgprot), middle breviscapine group (24.9 (14.7, 28.9) U/mgprot), and high breviscapine group (28.0 (21.9, 39.1) U/mgprot) were significantly increased ( P<0.05). Compared with 15.7 (13.7, 25.6) U/mgprot in saline group, the CAT activities in the supernatant of renal tissue of rats in middle breviscapine group and high breviscapine group were significantly increased ( P<0.05). Compared with that in low breviscapine group, the CAT activity in the supernatant of renal tissue of rats in high breviscapine group was significantly increased ( P<0.05). Compared with those in electric burn group and saline group, the levels of AOPP in the supernatant of renal tissue of rats in middle breviscapine group and high breviscapine group were significantly decreased ( P<0.05). Conclusions:After high-voltage electric burns, oxidative stress injury occur in the kidneys of rats, which is aggravated with time extension. Breviscapine can alleviate oxidative stress injuries in the kidneys of rats with high-voltage electric burns.

Objective To construct a prokaryotic expression vector of of the long QT syndrome(LQTS)associated C-terminal lobe of calmodulin(CaM)mutant E141G(C-lobeE141G)and to identify the expression,purification,and activity of C-lobeE141G.Methods A cDNA fragment was inserted into a PGEX-6p-3 plasmid vector and transferred into Escherichia coli BL21 receptor cells,and glutathione-S-trans-ferase(GST)fusion protein was induced by isopropyl thio-β-D galactoside(IPTG).Glutathione-Sepharose 4B beads were used to separate and purify GST-C-lobeE141G.After removing the GST label with protease,the purity and concentration of purified C-lobeE141G were detected using SDS-PAGE and BCA,respectively.The activity of purified C-lobeE141G was detected using the GST pull-down method and patch clamp technique.Results GST-C-lobeE141G fusion protein was highly expressed,and C-lobeE141G with high purity and concentration was obtained.The purified C-lobeE141G protein not only bound to CaV1.2 calcium channels,but also rescued the channel activity from run-down in the ventricular myocytes of rat hearts.Conclusion This study successfully constructed a prokaryotic expression vector of C-lobeE141G,which provides a material basis for the study of the mechanism of LQTS mediated by C-lobe mutations in CaM.

Objective:To design and construct a bone nonunion organoid on chip and explore the mechanism of aseptic bone nonunion.Methods:First a semi-open microfluidic chip was designed, on which human bone marrow mesenchymal stromal cells (BMSC), human fetal lung fibroblast 1, (HFL1) and human umbilical vein endothelial cells (HUVEC) were co-cultured, and a three-dimensional organ on chip system was established. Different proportions of HFL1 and HUVEC were co-cultured with BMSC, which were divided into the control group (HFL1∶HUVEC=1∶1), the fibrosis group (HFL1∶HUVEC=3∶1) and the vascularization group (HFL1∶HUVEC=1∶3). The osteogenic differentiation of BMSC was observed by alkaline phosphatase (ALP) and Alizarin red staining. The transcription level of osteogenic marker genes SP7, RUNX2, ALPL, and BGLAP, and vascularization related genes KDR and VWF were analyzed by qPCR. The expression levels of RUNX2 and ALP were determined by Western Blot. Results:In the co-culture system of BMSCs, HFL1, and HUVECs, BMSCs exhibited normal growth and apparent biomineralization behavior. Endothelial cells were capable of forming structured vascular networks, confirming the successful establishment of the system. Compared to the baseline group, the fibrotic group showed no significant decrease in BMSC osteogenic differentiation. The relative expression levels of the mineralization marker genes ALPL and BGLAP were 0.55±0.19 ( P<0.001) and 0.42±0.27 ( P<0.001), respectively. Vascularization genes KDR and VWF were downregulated, with relative expression levels of 0.49±0.17 ( P<0.001) and 0.49±0.21 ( P<0.001). In contrast, in the vascularized group, BMSC osteogenic differentiation genes SP7, RUNX2, ALPL, and BGLAP were upregulated, with relative expression levels of 2.91±0.52 ( P<0.001), 3.83±1.87 ( P<0.001), 3.22±1.29 ( P<0.001), and 5.21±1.46 ( P<0.001), respectively. Vascularization genes KDR and VWF were also upregulated, with relative expressions of 8.24±2.84 ( P<0.001) and 5.32±1.67 ( P<0.001). Western blot results indicated increased expression of RUNX2 and ALP in the vascularized group and decreased expression in the fibrotic group. Conclusion:The bone nonunion organoid on chip could partially simulate the local microenvironment of bone nonunion. Fibrosis may lead to a significant decrease in bone formation ability and vascularization level, which might be an important reason for the occurrence of aseptic bone nonunion.

Objective:To investigate the effects of anterolateral thigh chimeric perforator flap in repairing complex wounds of foot and ankle.Methods:A retrospective observational study was conducted. From May 2018 to June 2022, 23 patients who met the inclusion criteria were admitted to the First Affiliated Hospital of Air Force Medical University to repair complex wounds of foot and ankle with anterolateral thigh chimeric perforator flaps, including 15 males and 8 females, aged from 20 to 66 years. The wounds were all accompanied by bone exposure and defects, and were complicated with varying degrees of infection. All patients underwent debridement and continuous vacuum sealing drainage treatment for 1 week in stage Ⅰ, with the skin and soft tissue defect area after debridement being 10 cm×5 cm to 22 cm×7 cm. In stage Ⅱ, the anterolateral thigh chimeric perforator flap was used to cover the defective wound, of which the muscle flap was used to fill the deep invalid cavity of the ankle joint or cover bone and internal fixation exposures, and the skin flap was used to cover the superficial wound, with the area of the skin flap ranging from 11 cm×6 cm to 23 cm×8 cm, and the area of the muscle flap ranging from 4.0 cm×2.5 cm to 8.0 cm×5.0 cm. The survival of the flap was observed after operation. During follow-up, the color, texture, appearance, and complications of the flap were observed, the function of ankle joint and its range of dorsiflexion motion and plantar flexion motion were measured, and the scar hyperplasia and muscular hernia in donor area were observed.Results:Ecchymosis and epidermal necrosis occurred at the tip of the flap in 1 patient on 5 days after operation and healed after dressing change for 1 week; the other flaps of patients survived successfully. After 6 to 40 months of follow-up, the color, texture, and shape of flaps were good, but 1 patient was not satisfied with the shape of the flap because of flap swelling; the ankle joint movement was basically normal, the dorsiflexion motion was 15-30°, and the plantar flexion motion was 20-45°; the scar hyperplasia in the donor area of the flap was not obvious, and no muscular hernia occurred.Conclusions:The anterolateral thigh chimeric perforator flap can effectively fill the deep invalid cavity of ankle joint and cover the superficial wound at the same time, with minimal damage to the donor site. So it is an ideal flap for repairing the complex wounds of foot and ankle.

Many human genetic diseases, including Hutchinson-Gilford progeria syndrome (HGPS), are caused by single point mutations. HGPS is a rare disorder that causes premature aging and is usually caused by a de novo point mutation in the LMNA gene. Base editors (BEs) composed of a cytidine deaminase fused to CRISPR/Cas9 nickase are highly efficient at inducing C to T base conversions in a programmable manner and can be used to generate animal disease models with single amino-acid substitutions. Here, we generated the first HGPS monkey model by delivering a BE mRNA and guide RNA (gRNA) targeting the LMNA gene via microinjection into monkey zygotes. Five out of six newborn monkeys carried the mutation specifically at the target site. HGPS monkeys expressed the toxic form of lamin A, progerin, and recapitulated the typical HGPS phenotypes including growth retardation, bone alterations, and vascular abnormalities. Thus, this monkey model genetically and clinically mimics HGPS in humans, demonstrating that the BE system can efficiently and accurately generate patient-specific disease models in non-human primates.
Animals ; Disease Models, Animal ; Female ; Gene Editing ; Humans ; Lamin Type A/metabolism* ; Macaca fascicularis ; Progeria/pathology*

Objective To introduce and discuss the efficacy of a new technique to perform transperitoneal single-docking robot-assisted laparoscopic nephroureterectomy (RNU).Methods A total of 44 patients diagnosed with urothelial neoplasm of the renal pelvis or were investigated from January 2016 to November 2019.RNU was performed by a single surgeon.Among the 44 patients,31 were male,and 13 were female.The median age was 63 (IQR:58-71).The median body mass index (BMI) was 23.08 (IQR:21.55-24.60) kg/m2.All operations were performed with general anesthesia.The patients were positioned 80 degrees flank with the diseased side up,and the head was tilted 10 degrees downwards.The camera port was placed one finger lateral to the umbilicus.For the right-sided tumors,robotic arm 1 was inserted through the trocar on the right pararectus line,8 cm above the umbilicus,and robotic arm 2 was inserted through the trocar on the same line,8 cm below the umbilicus.Assistant trocar 1 was placed where the anterior midline joins the perpendicular bisector of the camera port and robotic 2,and assistant trocar 2 was placed below the xiphoid process.For the left-sided tumors,all trocars were centrosymmetric to that of the right-sided tumors,except that assistant port 2 was placed 3 finger width above the pubic symphysis.The peritoneum was incised along the Toldt line,and the inferior vena cava was isolated (for left sided tumor,the abdominal aorta was isolated instead).The renal artery and vein were clipped with Hem-o-lok and ligated,and the kidney were isolated.The ureter was identified and isolated downwards across the common iliac artery and then clipped distal to the tumor site.The bladder cuff was resected and sutured under the laparoscopy.Results The median operation time was 145 (IQR:130-175) min,with the median console time of 119 (IQR:108.5-136.0) min,the anastomosis of bladder cuff of 12 min,and the median estimated blood loss of 50 (20-100)ml.After the surgery,6 Clavien-Dindo grade 2 complications occurred,including 2 chylous leakage,1 hemostasis,1 blood transfusion,1 deep vein thrombus,and 1 acute coronary syndrome.The median length of stay (LOS) was 8 (IQR:6.5-10.0) d.The median length of follow-up was 12 months.In total,5 patients were dead,including 3 cancer-specific death.Four recurrence occurred and caused 3 death.The 2-year overall survival and progression-free survival were 68.2％ and 77.9％,respectively.Conclusions The technique of RNU with simultaneous bladder cuff excision (BCE).Our technique improved the surgical outcome.The perioperative complication rate was low,and the short-term survival outcomes were satisfactory.

Objective:To analyze the changes of relevant indicators in reproductive health status among Bangladeshi women from 1999 to 2018 and to assess whether the 2030 Sustainable Development Goals (SDGs) can be achieved.Methods:Data were obtained from both the Bangladesh Demographic and Health as well as from the Maternal Mortality and Health Care Surveys. The trends of SDGs indicators related to reproductive health from 1999 to 2018 were analyzed and compared, and the average annual rate of change was calculated. Development index was used to assess the difficulty of achieving the SDGs.Results:The maternal mortality rate increased first and then leveled off from 2001 to 2016. From 1999 to 2018, the coverage of reproductive health care services and the proportion of women who had the right to make the decision on their own health care service, were generally increasing. Proportion of the following areas as: "contraceptive needs, women who consider that partner violence is justified, the rate of early marriage, and the rate of early childbearing etc.", were declining at various degrees. Development index of the antenatal care coverage, rate of delivery in medical facilities, percentage of live births attended by medically trained providers and the rate of postnatal care etc., were less than 1. The development indices of the maternal mortality rates were close to 1, while all the other indicators were greater than 1. Conclusions:The reproductive health-related SDGs indicators in Bangladesh appeared somehow degrees of progress from 1999 to 2018. However, for most indicators, the average annual rate of change was still lower than the expected to achieve the 2030 target which called for acceleration in the next few years.

Objective To investigate the effect of intravenous tranexamic acid (TXA) on perioperative hidden blood loss in percutaneous pedicle screw fixation for thoracolumbar fractures.Methods A prospective study was conducted in the 113 patients who would be subjected to percutaneous pedicle screw fixation for thoracolumbar fracture from January 2017 to December 2017.They were randomly assigned into an observation group (n =58) receiving intravenous drip of 15 mg/kg TXA 30 minutes preoperation or a control group (n =55) receiving intravenous drip of normal saline solution 30 minutes preoperation.The total blood loss and hidden blood loss 24 hours postoperation,D-dimer volume,incidences of deep vein thrombosis and other complications were recorded and compared between the 2 groups.Results There were 54 patients in the observation group and 50 patients in the control group for statistic analysis.The observation group had significantly less total blood loss (319.0 ± 140.5 mL) and hidden blood loss (242.0 ± 143.4 mL) 24 hours postoperation than the control group (418.7 ± 188.1 mL and 354.7 ± 181.9 mL,respectively) (P ＜ 0.05).There were no significant differences between the 2 groups in operation time or intraoperative blood loss (P ＞ 0.05).The volume of postoperative D-dimer was significantly higher than the preoperative value in both groups (P ＜ 0.05).No thromboembolic events occurred in either group.Conclusion Intravenous TXA may significantly reduce intraoperative hidden blood loss with no increased rik of thromboembolic events in percutaneous pedicle screw fixation for thoracolumbar fractures.