Study of molecular markers of plasma exosomal proteins in patients with spinal cord injury / 中华骨科杂志

Objective:To screen plasma exosomal protein molecular markers in patients with spinal cord injury (SCI) by applying Label-Free quantification and bioinformatics analysis.Methods:Fifty plasma specimens from the First Affiliated Hospital of Nanjing Medical University (from January 2021 to June 2022) were collected from SCI patients and healthy people, respectively. Plasma exosomes were isolated using ultracentrifugation and identified by transmission electron microscopy, nanoparticle tracking analysis and western blot. Plasma exosomal differentially expressed proteins (DEPs) were analyzed using Label-Free quantitative proteomics, and DEPs were characterized, annotated, and enriched based on Gene Ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) databases. The screened DEPs were validated by western blot and enzyme linked immunosorbent assay (ELISA) using plasma exosomal specimens.Results:According to the spinal cord injury classification of the American Spinal Injury Association, 14 cases were grade A, 19 cases were grade B, 12 cases were grade C, and 5 cases were grade D. Plasma exosomes of SCI patients and control groups showed typical cup-like morphology, with diameters mainly ranging from 30-200 nm. A total of 493 exosomal proteins were identified by Label-Free quantification, and 126 proteins were screened for differential expression, of which 38 were up-regulated and 88 were down-regulated. GO annotation revealed that DEPs were mainly involved in functions such as protein activation cascade, complement activation and immune response. KEGG pathway analysis revealed that DEPs were involved in biological pathways such as complement and coagulation cascade reactions, proteasome and neurodegenerative disease pathways. Two candidate proteins, APOB and S100A9, were initially screened based on quantitative results from proteomics and bioinformatics analyses. Western blot results showed that the relative expression of S100A9 protein in plasma exosomes of 30 SCI patients (1.62±0.19) was elevated compared with that of 30 control groups (0.86±0.24), and the difference was statistically significant ( t=8.55, P<0.001), while the relative expression of APOB protein (1.06±0.13 and 1.02±0.23) were not statistically significant ( t=0.46, P=0.653). The results of ELISA analysis showed that the expression of S100A9 in plasma exosomes of patients with different degrees of SCI (grade A 197.7±11.7 pg/ml, grade B 151.7±15.2 pg/ml, grade C 136.3±14.7 pg/ml) had statistical significance ( F=69.94, P<0.001), the higher the severity of SCI, the higher the expression of S100A9 in plasma exosomes (A vs. B, q=13.11, P<0.001; A vs. C, q=15.66, P<0.001; B vs. C, q=4.19, P=0.005). Conclusion:S100A9 is a potentially valid plasma exosomal molecular marker for assessing the severity of SCI.

Clinical guideline for spinal reconstruction of osteoporotic thoracolumbar fracture in elderly patients (version 2022) / 中华创伤杂志

Osteoporotic thoracolumbar fracture in the elderly will seriously reduce their quality of life and life expectancy. For osteoporotic thoracolumbar fracture in the elderly, spinal reconstruction is necessary, which should comprehensively consider factors such as the physical condition, fracture type, clinical characteristics and osteoporosis degree. While there lacks relevant clinical norms or guidelines on selection of spinal reconstruction strategies. In order to standardize the concept of spinal reconstruction for osteoporotic thoracolumbar fracture in the elderly, based on the principles of scientificity, practicality and progressiveness, the authors formulated the Clinical guideline for spinal reconstruction of osteoporotic thoracolumbar fracture in elderly patients ( version 2022), in which suggestions based on evidence of evidence-based medicine were put forward upon 10 important issues related to the fracture classification, non-operative treatment strategies and surgical treatment strategies in spinal reconstruction after osteoporosis thoracolumbar fracture in the elderly, hoping to provide a reference for clinical treatment.

Surgical safety of cervical pedicle screw placement with orthopaedic surgery robot system / 中华骨科杂志

Objective:To evaluate the accuracy and safety of cervical pedicle screw (CPS) placement under orthopaedic robot navigation system guidance.Methods:From March 2019 to February 2021, the data of 33 patients (19 males and 14 females, aged from 26 to 75 years, with an average age of 50.5 years) treated with pedicle screw fixation with the assistance of orthopaedic surgery robot through the posterior cervical spine were retrospectively analyzed. In clinical diagnosis, there was upper cervical fracture with instability in 14 patients (fracture nonunion in 2 patients), upper & subaxial cervical fracture in 1 patient, cervical spinal cord injury with spinal stenosis in 2 patients, cervical spinal stenosis in 9 patients, occipitocervical deformity in 2 patients, post-operative revision of cervical spondylosis in 2 patients, cervical intraspinal tumor in 3 patients. A total of 151 CPSs were inserted in C 1-C 7 using robot navigation system based on intraoperative three-dimensional C-arm fluoroscopy to assist in screw placement in posterior cervical surgery. Among them, 74 screws were implanted into upper cervical spine; 77 screws were implanted in the lower cervical spine. CT was used to obtain image data within 7 days after operation, and Neo classification was used to evaluate the accuracy of cervical pedicle screw placement. The patients were followed up for 2 weeks to observe the clinical symptoms and signs, and to determine whether there were surgical complications such as nerve and blood vessel injury and incision infection. Results:According to Neo classification, 91.4% (138/151) screws were completely contained in the pedicle without breaking through the pedicle cortex (grade 0). Among them, the accuracy of C 1 screws was 97.1% (34/35), C 2 screws was 92.3% (36/39), C 3 screws was 88.2% (15/17), C 4 screws was 71.4% (10/14), C 5 screws was 85.7% (12/14), C 6 screws was 93.3% (14/15), C 7 screws was 100.0% (17/17). The screw accuracy was highest in C 7, the lowest in C 4. The Kruskal-Wallis H test was performed on the accuracy of screw placement in different cervical level, and the results showed that there was no statistical difference (χ 2=1.31, P=0.971). However, a total of 13 screws were found to perforate the cortex of pedicle, although any neural or vascular complications associated with CPS placement were not encountered. Among them, 9 screws were found to perforate laterally, and 4 screws were found to perforate medially. No postoperative incision infection occurred in all cases. Conclusion:The safety of CPS placement can be effectively guaranteed with the assistance of the orthopaedic robot system.

Correlation between physical exercise,screen time and mental sub-health among Chinese adolescents / 中国学校卫生

Objective@#To understand the relationships between video time, exercise time and the mental sub-health of Chinese adolescents, and to assist the development of Chinese adolescents’ mental health.@*Methods@#In this study, 16 545 adolescents aged 13-22 years in six administrative regions of China were surveyed using an adolescent sub-health multi-dimensional assessment questionnaire (MSQA), and daily physical exercise time, video screen time and other indicators were recorded. Binary Logistic regression analysis was used to understand adolescents’ mental sub-health and the correlation between video time and exercise time.@*Results@#Detection rate of mental sub-health status in adolescents with video time ≤2 h/d was lower than that of adolescents with video time >2 h/d(19.1%，22.1%), and the detection rate of adolescents with exercise time ≤60 min/d(22.1%，17.7%) was higher than that of adolescents with exercise time >60 min/d. These differences were statistically significant (χ2=14.47, 6.97, P<0.05). Binary Logistic regression analysis showed that the risk of mental sub-health status for Chinese adolescents whose screen time was more than 2 h/d was 1.20 times that of those with screen time ≤2 h/d, and the difference was statistically significant (P<0.01). The risk of mental sub-health for students whose exercise time was > 60 min/d was 0.86 times that of students who exercised ≤ 60 min/d, and the difference was statistically significant (P<0.05).@*Conclusion@#Screen time >2 h/d and exercise time <60 min/d were negative factors leading to mental sub-health symptoms in Chinese adolescents.It is proposed to jointly promote the healthy adolescent development through health education,as well as positive family and social environment.

Correlation between physical fitness index and mental sub-health among Chinese adolescents / 中国学校卫生

Objective@#To investigate the association between mental sub-health and physical fitness of Chinese adolescents, to provide a reference for promoting the physical and mental health of Chinese adolescents.@*Methods@#A total of 16 545 adolescents (13-22 years) were selected by random cluster sampling in six major administrative regions in China. The psychological part of the Multidimensional Sub-health Questionnaire of Adolescents (MSQA) and the physical fitness index test were used to assess mental sub-health and physical fitness, respectively. The chi-square test and Logistic regression analysis were used to analyze and compare the relationships between different levels of physical fitness and mental sub-health.@*Results@#The overall detection rate of mental sub-health status among high-grade physical fitness index adolescents was 11.9%, and the detection rate among low-grade physical fitness index youths was 26.0%, and the difference was statistically significant (χ2=970.73，P<0.05). The overall detection rate among high-grade physical fitness index boys was 11.1%, and that of low-grade physical fitness index boys was 24.4%. The difference was statistically significant (χ2=566.12，P<0.05). The overall detection rate of mental sub-health status among high-level physical fitness index girls was 12.8%, and that among low-level physical fitness index girls was 27.6%, and the difference was statistically significant (χ2=412.25，P<0.05). After adjusting for gender, age, BMI, and region in the Logistic regression model, the detection rate of mental sub-health status of adolescents with low-grade physical fitness index was 2.35 times higher than that of high-grade physical fitness index adolescents(95%CI=2.12-2.61).@*Conclusion@#Adolescents with poor physical fitness have a higher risk of mental sub-health.Attention should be paid to adolescent physical fitness development to comprehensively improve physical and mental health development.

Correlation between dietary behavior and mental sub-health among Chinese adolescents / 中国学校卫生

Objective@#To determine the relationship between mental sub-health and dietary behavior among Chinese adolescents, and to provide a scientific basis for improving adolescent mental sub-health through healthy dietary behavior.@*Methods@#A total of 16 545 adolescents aged 13 to 22 years were sampled by random cluster sampling method in six administrative regions of China. A questionnaire survey was conducted to investigate adolescents’ dietary behaviors and mental sub-health status.@*Results@#The proportion of boys consuming breakfast, snacks, carbonated drinks, vegetables, fish and dairy products was 76.2%, 20.2%, 19.0%, 78.4%, 52.4% and 59.2%, respectively, while the proportion of girls was 79.2%, 28.6%, 12.6%, 78.3%, 43.2% and 54.9%, respectively. Except for the "vegetable" option, dietary behaviors showed significant sex differences(χ2=20.79,320.10,229.06,150.27,32.21,P<0.01). In terms of mental sub-health, the detection rates of male adolescents’ mental sub-health status, behavioral sub-health and social sub-health were 20.7%, 26.0% and 17.2%, respectively, while those of female adolescents were 18.6%, 24.1% and 14.8%, respectively. The differences between boys and girls were statistically significant (χ2=17.32,7.66,17.46,P<0.01). Controlling for age and gender, breakfast "normally eating" and "occasionally eat", vegetables "normally eating" and "occasionally eat", fish "normally eating" and "occasionally eat", milk, dairy products "normally drink" and "occasional drink",was negatively associated with teenagers’ psychological sub-health (OR=0.60,0.73;0.50,0.65;0.74,0.77;0.73,0.69,P<0.05).@*Conclusion@#Healthy dietary behavior could be protective to avoid adolescent mental sub-health.Nutritional lectures and guideline books are needed among students and their parents.Nutritionists are encouraged to provide healthy nutritional advice to school canteen.

Correlation between Chinese adolescent mental sub-health and muscle strength index / 中国学校卫生

Objective@#To understand the mental sub-health status of Chinese adolescents and its correlation with muscle strength index, and to provide information for relevant research in mental health and muscle strength development of Chinese adolescents.@*Methods@#A total of 16 545 adolescents aged 13-22 year-old in six administrative regions of China were administered with the Adolescent Sub-Health Multidimensional Assessment Questionnaire (MSQA). Muscle strength indicatros were tested and its relations with mental sub-health were analyzed.@*Results@#The detection rates of Chinese adolescents emotional problems, character problems, social adjustment difficulties, and mental sub-health status were 25.5%, 25.0%, 16.0%, and 19.7%, respectively. The detection rates of mental sub-health status of adolescents in the group of muscle index <P25, P25-P75, >P75 were 30.3%, 19.0%, and 10.4%, respectively, and the difference was statistically significant(χ2=522.03, P<0.01). Logistic regression analysis showed that junior high school(OR=2.55), high school(OR=2.27), male students(OR=1.15), muscle index <P25 (OR=3.81), P25-P75 (OR=2.03) group were positively correlated with mental sub-health(P<0.01).@*Conclusion@#There is a correlation between the mental sub-health of Chinese adolescents and the muscle strength index. The higher the muscle strength index, the lower detection rate of mental sub-health.

Selective decompression of lumbar root canal and pedicle screw fixation after laminectomy for the treatment of elderly lumbar spinal stenosis:indications and prognosis / 中国组织工程研究

BACKGROUND:Due to complicated and special lumbar spinal stenosis disease and different degrees of lumbar degeneration in the elderly, it requires very careful choice of repair methods and repair technology. OBJECTIVE:To investigate the indications and prognosis effect of the treatments of elderly lumbar spinal stenosis by selective decompression of lumbar root canal under direct vision and laminectomy. METHODS:Clinical data of 167 elderly patients with lumbar spinal stenosis were retrospectively analyzed. A total of 82 patients were treated with selective decompression of lumbar root canal as the selective decompression group, with a clear nerve root compression but without central canal stenosis. A total of 85 patients were treated with laminectom and treated with pedicle screw fixation as the whole lamina cut group, with distinct central canal stenosis. The indications were analyzed between the two groups. Clinical effects were assessed using Japanese Orthopaedic Association and Oswestry Disability Index before and after surgery. RESULTS AND CONCLUSION:(1) Al patients were operated successful y. There was no serious complication during treatment. (2) Japanese Orthopaedic Association and Oswestry Disability Index were significantly improved at last fol ow-up in two groups compared with preoperation (P0.05). Clinical symptoms disappeared or relieved at last fol ow-up in two groups. The prognosis in two groups had significantly improved. (3) Results indicated that laminectomy and pedicle screw fixation in elderly patients with lumbar spinal stenosis and central canal stenosis obtained significant effects. For elderly patients with lumbar spinal stenosis but without central canal stenosis, selective decompression of lumbar root canal under direct vision was given, and it is effective and reliable. The two methods are suitable for different patients, and are effective and reliable way to repair.

Different concentrations of mitomycin C to prevent peridural adhesion in rats after laminectomy: A qualitative and quantitative research / 中国组织工程研究

BACKGROUND:At present,using membrane materials to separate spinal dura mater and scar tissue or using semiliquid materials to surround the dimension of operation are very common after laminectomy.However,therapeutic eflfects ale not satisfactory.Inhibition to the proliferation of fibroblasts,which are the main components of repairing cells,and regulating collagen metabolism have become a hot spot for preventing and treating pathological scar by a biological method.OBJECTIVE:To compare the therapeutic effects of topical application of different concentrations of mitomycin C (MMC)on preventing pefidural adhesion in rats after laminectomy by a qualitative and quantitative combined method.DESIGN:A completely randomized grouping.controlled animal experiment.SETTING:Department of Orthopaedics,Second People's Hospital of Lianyungang City.MATERIALS:Forty healthy adult male SD rats,weighing 200-220 g,were provided by the Animal Experimental Center,Nanjing Medical University.MMC was produced in Union Fermentation Co.,Ltd(Batch No.425ACI,Import drugs registration No.H20020163,Japan).METHODS:The study was performed at the Animal Laboratory Center,Nanjing Medical University,and the Basic Experimental Center,Medical College,Jiangsu University from June 2004 to October 2006.The 40 SD rats were ralndomly divided into 4 groups with 10 rats in each group:MMC high-,medium-,and low-concentration groups,and a control group.After anesthesia,each rat was removal of L1 vertebral plate.A defect(0.2 cm×0.5 cm)was created to expose duml mater.After hemostasia,cotton Pads soaked either with various concentrations ofMMC(0.1,0.05,0.01 g/L)or saline were covered on the laminectomy defects in the three MMC-treated groups and the control group for 5 minutes respeetively.The protocol was carried out in accordance with ethical guidelines for the use and care of animals.MAIN OUTCOME MEASURES:After the operation,4 rats were randomly selected from all anesthetized rats in each group,separately.The peridural scar tissue in the laminectomy segment was cut for calculating the contents of hydroxyproline.Spine columns in the laminectomy segment including Surrounding muscle tissue were resected for measuring irregular sear transverse area and counting the number 0ffibroblasts.The degree of peridural scar adhesion was evaluated by the light microscope.RESULTS:Forty rats were included in the final analysis.In the control group,peridural scar tissue was dense and closely adhered to dura mater.In the MMC high-concentration group.no noticeable peridural adhesion was found.and contents of hydroxyproline,collagen tissue area and the amount of fibroblasts in the scartissue were significantly reduced compared to control group(all P＜0.05).In the MMC medium-and low-concentration groups,contents of hydroxyproline,collagen tissue area and the amount of fibroblasts had reduced to different extents compared to control group.There was significant difference only in the amount of fibroblasts between the MMC mediumconcentration group and the control group(P＜0.05).Incontinuous adhesion between scar tissue and dura mater was found in the MMC medium-and low-concentration groups.CONCLUSION:Topical application of 0.1 g/L MMC can effectively reduce peridural scar tissue hyperplasia and avoid peridural scartissue adhesion afterlaminectomy.

Effects of spinal pedicle screw internal fixation at different extraversion angles Biomechanical evaluation / 中国组织工程研究

BACKGROUND: It has been demonstrated that pedicle screw internal fixation influencing factors involve screw structural morphology, thread parameter, bone density, moment size for tightening screw during operation, and depth of screw placement. There is little known about the correlation of pullout strength of spinal pedicle screw with device for transverse traction to extraversion angle. OBJECTIVE: To assess effect of the spinal pedicle screw with device for transverse traction on pullout strength at different extraversion angles. DESIGN: Repeated measurement. SETTING: Center for Bone Joint, the First Affiliated Hospital of Nanjing Medical University. PARTICIPANTS: This study was performed at Laboratory for Material Mechanics, Hehai University between June and November 2003. A total of 18 adult dried lumbar vertebrae (L1-5) were provided by Department of Anatomy, Nanjing Medical University, and recruited for this study. The protocol was approved by the hospital's Ethics Committee. The pedicle screw was made of stainless steel. Each pedicle screw had a diameter of 5.5 nun, total length of 150 nun (thread part 50 into included), and the same thread parameter. Electrical universal material machine (EW type) was provided by Laboratory for Material Mechanics of Hehai University. METHODS: Bone density was measured with a single photon bone density determinator. According to the bone density, the lumbar vertebrae were numbered and randomly divided into 3 groups with 6 lumbar vertebrae in each: extraversion angle 5 ° group, extraversion angle 15° group, and extraversion angle 30° group. ① Installation of pedicle screw and clamping apparatus: According to Wein-Stein method, one entry-point was selected at each side of lumbar vertebra, and at the sametime, extraversion angle 5°, 15° ,and 30° were respectively defined for extraversion angle 5° , 15° ,and 30° groups. A 50 mm-depth pinhole was drilled with a drill bit with a diameter of 3.0 nun. Pedicle screw was screwed into 50 nun, and its end part was connected to the device for transverse traction. Spinal vertebrae and the device for transverse traction were fixed with a specially made clamping apparatus. ② Determination of pullout strength and observation of pedicle and vertebral injury: Spinal vertebrae, on which pedicle screw and device for transverse traction were installed, was placed on a EW electrical universal material machine together with clamping apparatus for determining the pullout strength of pedicle screw. Sensor was connected to a computer to draw strength-displacement curve. The wave crest of the curve was considered the maximum pullout strength. At the same time, injuries to pedicle and vertebra caused by pullout of pedicle screw were observed. MAIN OUTCOME MEASURES: Pullout strength and injuries to pedicle and vertebra. RESULTS:①The mean maximum pullout strength of pedicle screw was respectively 0.878 167, 1.420 333, and 2.154 167 KN for extraversion angle 5° , 15 ° , and 30° groups. There was significant difference among the 3 groups (F = 12.554 22, P < 0.01). ② In the extraversion angle 5° group, 4 patients presented with cortical bone fracture which occurred at the entrance for pedicle screw, and 2 patients presented with fragmentation of junctional zone between pedicle and vertebral posterior edge; In the extraversion angle 15° group, 1 patient presented with cortical bone fracture which occurred at the entrance for pedicle screw, 4 patients presented with fragmentation of junctional zone between pedicle and vertebral posterior edge, and 1 patient presented with vertebral posterior coronal fragmentation; In the extraversion angle 30° group, 1 patient presented with cortical bone fracture which occurred at the entrance for pedicle screw, 2 patients presented with fragmentation of junctional zone between pedicle and vertebral posterior edge, and 3 patients presented with vertebral posterior coronal fragmentation. There was statistical significance in the intergroup rank-sum test (P < 0.01).CONCLUSION: During application of pedicle screw with device for transverse traction, proper accrescence of extraversion angle can increase pullout strength of the screw and enhance fixative strength, and excessive extraversion angle easily injures vertebra.

Experimental study on prevention of peridural adhesion after laminectomy with local different concentration mitomycin C / 中国矫形外科杂志

[Objective]To compare the effects of topical different concentration mitomycin C(MMC)in preventing postlaminectomy peridural adhesion.[Method]Laminectomies were performed at L1 in 40 rats.Cotton pads soaked either with 0.01 mg / ml(group L),0.05 mg /ml(group M),0.1 mg / ml(group H) MMC or saline(group C) were applied to the operative sites.The rats were killed 4 weeks after surgery.The specimens were prepared for determination of the degree of scar adhesion according to Rydell method,the content of Hydroxyproline(HOP),the area of peridural fibrosis and the count of fibroblasts.[Result]Dense peridural fibrosis with marked peridural adhesion showed in group C.No obvious adhesion formed in group H.In group M and L,peridural adhesion wasn't avoided.The content of HOP,the area of peridural fibrosis and the count of fibroblasts showed various degrees decrease in all MMC-treated groups.[Conclusion]Local application of 0.1 mg/ ml MMC may be a successful method of reducing postlaminectomy peridural fibrosis and completely avoided peridural adhesion.

Dedicated distribution of nerve growth factor in different forms / 中国组织工程研究

BACKGROUND: That the nerve growth factor(NGF) is capable of treating peripheral nerve injury has been broadly acknowledged. But it is not sure whether it is able to pass through blood brain barrier(BBB) to act on central nerve system. In this study, the NGF encapsulated in liposome was compared with NGF alone in their abilities of passing through BBB.OBJECTIVE: To compare the dedicated distribution of NGF in different forms using single photon emission computerized tomography(SPECT).DESIGN: It is a randomized controlled study with New Zealand rabbits as subject.SETTING: An affiliated hospital of Nanjing Medical College.MATERIALS:The trial was conducted in Nanjing Senke Medical Company and the Nuclear Medicine Department of the First Hospital of Nanjing Medical College from June 2003 to May 2004. The subjects were 19 New Zealand rabbits of either sex, weighting (2.0 ±0. 2) kg, from Anlimo Technology Company. [99Tcm] -NGF(labeling rate 98.9%, purity 99.7% )was made by Senke Medical Company. Liposome was provided by Shengyang Pharmaceutical College. Urethine solution(200 g/L) was from Pharmacy Department of NanJing Medical Collage.METHODS: [99Tcm]-NGF was encapsulated in liposome and was treated as the following: The liposomesA containing 1.48 × 108Bq[99Tcm] -NGF were injected into rabbits and its distribution percentage was analyzed with SPECT. The same amounts of[99Tcm] -NGF and[99Tcm] -NGF-ordinary liposomesB were treated in the same way.MAIN OUTCOME MEASURES: The ratio of concentration and radiation percentage of NGF in brain to those in the whole body.RESULTS: The[99Tcm]-NGF encapsulated in self-made liposomeA presented high radiation in the brain. But[99Tcm] -NGF alone was almost completely excreted through urinary system and[99Tcm] -NGF encapsuled in ordinary liposomeB was mostly phagocytized by liver reticuloendothelial system.CONCLUSION: The self-made NGF-liposomeA is brain-dedicated, which set a basis for drugs to pass through BBB.

Comparison of the biological stability of liposome-encapsulated nerve growth factor at different depot stages / 中国组织工程研究

BACKGROUND: Nerve growth factor (NGF) is characterized by poor stability both in vitro and in vivo, and liable to lose its bioactivity.OBJECTIVE: To study the stability of liposome-encapsulated NGF injection preserved under various conditions.DESIGN: A controlled study of liposome-encapsulated NGF.SETTING: Department of Surgery of the First Affiliated Hospital of Nanjing Medical University.MATERIALS: This study was carried out at the Central Laboratory of the First Affiliated Hospital of Nanjing Medical University between July 2002and March 2004. NGF from rat submaxillary gland was purified, encapsulated by liposome, and prepared into lyophilized dosage form before preserved under different conditions (at 4 ℃, room temperature, 40 ℃ or 40 ℃ with saturated humidity, respectively).METHODS: Chicken embryo dorsal root ganglion cultured in serum-free medium was used to evaluation the bioactivity of NGF in vitro. The dorsal root ganglion from 8-day-old chicken embryo was inoculated in a polylysine-coated 24-well culture plate and cultured in Dulbecco modified Ea-gle medium (DMEM) containing different testing samples. Only DMEM was used for culture in the negative control group, while DMEM containing NGF at different concentrations used in the positive control group. The ganglion was cultured at 37 ℃ with 50 mL/L CO2 and saturated humidity for 24 hours, and the growth of the nerve fibers was observed under an inverted microscope. The bioactivity of NGF was also evaluated in simulated condition in vivo by adding lyophilized liposome-encapsulated NGF and positive control NGF specimen into 0.5 mL rat serum, which, along with the blank control serum, was added into 2.5 mL DMEM at 0.5, 1, 2, 3, 4,6 hours and thoroughly mixed. The bioactivity of NGF was assessed accord-ing to the length and density of the dorsal root ganglion and graded the prominences (recorded as "++" or "+++ "), and very long and dense growth of the prominences (++++).MAIN OUTCOME MEASURES: In vitro bioactivity of NGF preserved for 10, 30, 60, and 90 days by testing the growth of cultured chick embryo dorsal root ganglion in serum-free DMEM and in test of rats serum containing NGF added at 0, 0.5, 1, 2, 3, 4, and 6 hours into DMEM.RESULTS: Lyophilized liposome-encapsulated NGF exhibited stable bioactivity (+++) after preservation at 4℃ and room temperature for 10-90days; at 40 ℃ for 10-60 days, the it retained its the bioactivity (+++),which, however, slightly decreased by 90 days (++); its bioactivity was preserved (+++) at 40 ℃ with saturated humidity for 10 days (+++), slightly decreased at 30-60 days (++) and noticeably lowered (+) at 90 days. When preserved for 0, 0.5, 1, 2, and 3 hours in rat seum, the NGF preparation retained stable bioactivity (++++ or +++), which slightly decreased at 4 hours and 6 hours (++).CONCLUSION: Liposome-encapsulated NGF has stable bioactivity but its preservation at relatively high temperature with high humidity is difficult.Lyophilized liposome-encapsulated NGF exhibits better bioactivity than NGF-liposome suspension after preservation under various conditions.

Effect of nerve growth factor on neuronal apoptosis after spinal cord injury in rats / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To explore the molecular mechanism of the protective effect of nerve growth factor (NGF) on injured spinal cord.</p><p><b>METHODS</b>The posterior T(8) (the 8th thoracic segment) spinal cords of 60 Wistar rats were injured by impacts caused by objects (weighing 10 g) falling from a height of 2.5 cm with Allen's way. Solution with nerve growth factors (NGF) was given to 30 rats (the NGF group) through a microtubule inserted into the subarachnoid cavity immediately, and at 2, 4, 8, 12 and 24 hours after spinal cord injury (SCI) respectively. Normal saline (NS) with same volume was given to the other 30 rats (the NS group) with the same method. And 5 normal rats were taken as the normal controls. The expression of bcl-2 and bax proteins in spinal cord was detected with immunohistochemistry. The apoptotic neurons in spinal cord were measured with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling of DNA fragments (TUNEL) staining.</p><p><b>RESULTS</b>The positive expression of bcl-2 protein was strong in the normal controls, but decreased in the NS group, and increased significantly in the NGF group as compared with that of the NS group (P<0.01). The positive expression of bax protein was also strong in the normal controls, but increased in the NS group, and decreased significantly in the NGF group as compared with that of the NS group (P<0.01). Apoptotic neurons were found in the NS group, and they decreased significantly in the NGF group as compared with that of the NS group (P<0.01).</p><p><b>CONCLUSIONS</b>NGF can protect the injured nerve tissues through stimulating the expression of bcl-2 protein, inhibiting the expression of bax protein and inhibiting the neuronal apoptosis after SCI.</p>

Effects of nerve growth factor on neuronal nitric oxide production after spinal cord injury in rats / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To explore the protective effects of nerve growth factor (NGF) on injured spinal cord.</p><p><b>METHODS</b>The spinal cord injury (SCI) model of Wistar rats was established by a 10 gx2.5 cm impact force on the T(8) spinal cord. NGF (60 microg/20 microl) was given to the rats of the treatment group immediately and at 2, 4, 8, 12, 24 hours after SCI. The level of neuronal constitutive nitric oxide synthase (ncNOS) and the expression of ncNOS mRNA in the spinal cord were detected by the immunohistochemistry assay and in situ hybridization method.</p><p><b>RESULTS</b>Abnormal expression of ncNOS was detected in the spinal ventral horn motorneuron in injured rats. The levels of ncNOS protein in the NGF group were significantly lower than those in the normal saline group (P<0.05 ). The ncNOS mRNA expression was found in the spinal ventral horn motorneuron in injured rats and the expression in the NGF group was significantly decreased compared with that in the normal saline group (P<0.01).</p><p><b>CONCLUSIONS</b>NGF can protect the injured tissue of the spinal cord by prohibiting abnormal expression of nitric oxide synthase and the neurotoxicity of nitric oxide.</p>

Effects of nerve growth factor on N-methyl-D-asparate receptor 1 after spinal cord injury in rats / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To explore the effects of the nerve growth factor (NGF) on N-methyl-D-asparate receptor 1 (NMDAR 1) after spinal cord injury.</p><p><b>METHODS</b>Spinal cord injury of Wistar rats was performed with Allen's method by a 10 gx2.5 cm impact on the posterior T8 spinal cord. NGF was given to the rats of the treatment group via subarachnoid space tube at once, 2, 4, 8, 12 and 24 hours after spinal cord injury, respectively. The expression of NMDAR1 mRNA in spinal cord was detected by in situ hybridization.</p><p><b>RESULTS</b>Rare expression sequence of NMDAR1 mRNA was found in rat spinal cord of the normal group. A strong expression sequence of NMDAR1 mRNA was found in rat spinal cord of the normal saline group. The expression of NMDAR1 mRNA in the NGF group was significantly decreased as compared with that in the normal saline group (P=0.01).</p><p><b>CONCLUSIONS</b>NGF can relieve damage of injured spinal cord by prohibiting the expression of NMDAR1 mRNA.</p>