Objective To investigate the effect of olfactory ensheathing cell culture medium (OECCM) on the growth of spinal cord neurons and its protective effect on the injured neurons by H2O2, and to disscuss the probable protective mechanisms of olfactory ensheathing cells (OECs). Methods The primary olfactory ensheathing cells (OECs) were isolated from olfactory bulb of adult SD rat, and OECCM were prepared. The morphology of OECs was observed by inverted phase contrast microscope, identified by rabbit-antiratlow-affinity nerve growth factor p75 (NGFRp75), and its purity were calculated.Primary spinal cord neurons were cultured from 15 to 17 days pregnant SD rats, and injury model of neurons were prepared by H2O2. OECCM and control culture medium were added into the normal spinal neurons (groups A, B). OECCM and control culture medium were added into the injured spinal neurons by H2O2 (groups C, D). In groups A and C, 200 μL of control culture medium was used; in groups B and D, 100 μL of control culture medium and 100 μL of OECCM were used. Then the growth index such as average diameter of neuron body, the number and length of neuron axons were measured. The viabil ities of normal and injured neurons were assessed by MTT. Results OECs showed bipolar or tripolar after 6-9 days of culture. Primary spinal cord neurons were round and bigger, and neuron axons grew significantly and showed bipolar after 5-7 days of culture. The immunocytochemisty of OECs by NGFRp75 showed that membrane were stained. The degree of purity was more than 90%. Primary spinal cord neurons grew well after 6-9 days of culture, and compared with group A, neurons of group B grew b, whose cell density and diameter were bigger. The average diameter of neuron body, the number and length of neuron axons were (33.38 ± 6.80) D/μm, (1.67 ± 0.80), and (91.19 ± 62.64) L/μm in group A, and (37.39 ± 7.28) D/μm, (1.76 ± 0.82), and (121.33 ± 81.13) L/μm in group B; showing statistically significant differences (P lt; 0.05). The absorbency (A) value of neurons was 0.402 0 ± 0.586 9 in group A and 0.466 0 ± 0.479 0 in group B; showing statistically significant difference (P lt; 0.01). After 2 hours of injury by H2O2, the cell density of spinal cord neurons decreased, and neuron axons shortened. The A value of injured neurons was 0.149 0 ± 0.030 0 in group C and 0.184 0 ± 0.052 0 in group D, showing statistically significant difference (P lt; 0.01). Conclusion The results above suggest that OECCM could improve the growth of spinal cord neurons and protectthe injured neurons. The neurotrophic factors that OECs secrete play an important role in the treatment of spinal cord injury.
Objective The biological treatment of intervertebral disc degeneration becomes a research hotspot in recentyears. It is necessary to find an effective approach to induce bone marrow mesenchymal stem cells (BMSCs) differentiate to disc cells which could make appl ication of cell transplantation as a treatment of intervertebral disc degeneration. To investigate the effects of the recombinant plasmid pcDNA3.1IE-SOX9Flag on differentiation of rabbit BMSCs into nucleus pulposus-l ike cells. Methods The eukaryotic expression vector of pcDNA3.1IE-SOX9Flag was constructed. Rabbit BMSCs were isolated and cultured from one-month-old New Zealand white rabbits and were induced into osteogenetic cells in the osteogenesis supplement medium; and the cell surface markers were detected by flow cytometry. The cells at the 3rd passage were randomly divided into 3 groups: in transfected group, the cells were transfected with recombinant plasmid pcDNA3.1IE-SOX9Flag; in negative control group, the cells were transfected with plasmid pcDNA3.1; and in blank control group, the cells were treated with the media without recombinant plasmid. After selected by G418 for 7 days, the cells were harvested and RT-PCR was employed to assay SOX9 mRNA and collagen type II gene (Col2al) mRNA expressions in BMSCs. The expression of SOX9 protein was assayed by Western blot and collagen type II expression was also observed by immunohistochemical staining. Results The SOX9 eukaryotic expression vector was constructed successfully. The BMSCs after 5 days of osteogenetic induction were positive for the alkal ine phosphatase staining. What was more, CD44 expression was positive but CD34 and CD45 expressions were negative. The transfection efficiency was 34.32% ± 1.75% at 72 hours after transfection. After 2 weeks of transfection, BMSCs turned to polygonal and ell iptical. And the cell prol iferation was gradually slow which was similar to the growth characteristic of nucleus pulposus cells. RT-PCR identification showed that SOX9 mRNA and Col2al mRNA expressions were positive in transfected group, and were negative in 2 control groups. Western blot detection showed that SOX9 protein expressed in transfected group but did not express in the control groups. At 2 weeks after transfection, the result of the immunohistochemicalstaining for collagen type II was positive in transfected group. Conclusion The recombinant plasmid pcDNA3.1IE-SOX9Flag can be successfully transfected into rabbit BMSCs, the transfected BMSCs can differentiate into nucleus pulposus-l ike cells, which lays a theoretical foundation for treatment of intervertebral disc degeneration with BMSCs transplantation.
To make a rabbit model of Perthes disease and to explore the change and its significance of VEGF expression in the femoral head. Methods Twenty-four 3-month-old New Zealand rabbits (weighing 1.6-1.8 kg) were randomly divided into experimental group (n=16) and control group (n=8). A rabbit model of Perthes disease was made by excision of left l igamentum teres and retinacular blood suppl ies of femoral head. The gross appearance, X-ray film and histological observations were made and the immunohistochemistry and VEGF mRNA in situ hybridization were carried out1, 2, 4, 8 weeks after operation. Results The rabbit model of Perthes disease was made successfully; only 1 was infected5 days after operation and was made quit. The gross appearance: The femoral heads had no necrosis changes in control group at every time. The femoral heads became coarse, tarnish and smaller, and even collapsed in experimental group. The HE staining observation: The femoral heads had no necrosis changes in control group at every time after operations. New vessels and granulation tissues grew into the necrosis part in the experimental group 4 weeks and 8 weeks after operations. New bone could be seen in repaired bone. Immunohistochemistry staining: In the epiphyseal cartilage of the femoral heads in control group, an intensive VEGF immunoreactivity (VEGF-IR) was found in the hypertrophic zone with a low level of VEGF-IR in the prol iferative zone. At 1 week after operation, the percentage of VEGF+ cells in the prol iferative zone of the femoral heads in experimental group was increased compared with that of the femoral heads in control group. The percentage of VEGF+ cells in the hypertrophic zone of the femoral heads in experimental group was significantly decreased compared with that of the femoral heads in control group. At 8 weeks after operation, VEGF-IR was observed throughout the epiphyseal cartilage surrounding the bony epiphysis in the femoral heads in experimental group. The percentage of VEGF-positive cells in the prol iferative zone of the femoral heads in experimental group was significantly increased compared with that of the normal heads. The hypertrophiczone of the femoral heads in experimental group had a similar percentage of the VEGF+ cells to the femoral heads in control group when endochondral ossification was restored at 8 weeks. There were statistically significant differences in the ratios of VEGF+ cells in the prol iferative zone of femoral head 1, 2, 4, 8 weeks after operations (P lt; 0.01); in the ratios of VEGF+ cells in the hypotrophic zone of femoral head 1, 2, 4 weeks after operations (P lt; 0.01) between experimental group and control group. In situ hybridization results: The results were similar to that of histology. VEGF mRNA expression in the hypertrophic zone of epiphyseal catilage after necrosis were lower. VEGF mRNA expression in the prol iferative zone of epiphyseal catilage after necrosis increased. VEGF mRNA expression in the hypertrophic zone of epiphyseal cartilage in experimental group could be seen again after endochondral ossification was repaired. Conclusion It is possible that VEGF may act as a key regulator that couples angiogenesis, cartilage remodel ing, and ossification after ischemic damage to restore endochondral ossification in the epiphyseal cartilage.
Objective The senescence and death of nucleus pulposus (NP) cells are the pathologic basis of intervertebral disc degeneration (IVD). To investigate the molecular phenotypes and senescent mechanism of NP cells, and to identify the method of alleviating senescence of NP cells. Methods The primary NP cells were harvested from male SpragueDawley rats (8-10 weeks old); the hypoxia inducible factor 1α (HIF-1α), HIF-1β, matrix metalloproteinase 2 (MMP-2), andcollagen type II as phenotypic markers were identified through immunocytochemical staining. RT-PCR and Western blot were used to test the silencing effect of NP cells after the NP cells were transfected with p53 and p21 small interference RNA (siRNA). Senescence associated-β-galactosidase (SA-β-gal) staining was used to test the senescence of NP cells, flow cytometry to test the change of cell cycle, the growth curve analysis to test the NP cells prol iferation. Results Immunocytochemical staining showed that NP cells expressed HIF-1α, HIF-1β, MMP-2, and collagen type II. RT-PCR and Western blot showed that the relative expressions of mRNA and protein of p53 and p21 were significantly inhibited in NP cells at passage 35 after transfected with p53 and p21 siRNA. The percentage of SA-β-gal-positive NP cells at passage 35 was significantly higher than that at passage 1 (P lt; 0.001). And the percentage of SA-β-gal-positive NP cells in the p53 siRNA transfection group and p21 siRNA transfection group were significantly lower than that in control group (Plt; 0.001). The flow cytometry showed that the G1 phase of NP cells in p53 siRNA transfection group and p21 siRNA transfection group was significantly shorter than that in control group (P lt; 0.05), but the S phase of NP cells in p53 siRNA transfection group and p21 siRNA transfection group were significantly longer than that in control group (P lt; 0.05). In addition, the growth curve showed that the growth rate of NP cells could be promoted after transfection of p53 and p21 siRNA. Conclusion The senescence of NP cells can be alleviated by silencing of p53 and p21. The effect of alleviating senescence can even ameliorate the progress of IVD and may be a useful and potential therapy for IVD.
Objective To investigate the prevalence and risk factors of degenerative disc disease (DDD) in pilots. Methods From January 2021 to May 2022, pilots were surveyed using a whole group sampling method and relevant imaging data were collected. The contents of the survey included basic information, DDD-related information, flight-related information, and personal habits. The prevalence of DDD was calculated, and univariate χ2 test, t-test, and multivariate logistic regression analysis were performed for the diseased and healthy groups to screen the risk factors of DDD. Results A total of 170 copies of questionnaire were sent out and 162 valid copies were returned. The prevalence of DDD was 47.5% (77/162), including 27.8% (45/162) for cervical spondylosis, 29.6% (48/162) for lumbar disc herniation, and 3.1% (5/162) for degenerative lumbar spondylolisthesis. The results of univariate analysis showed that body mass index (t=2.594, P=0.010), driving age (t=2.160, P=0.032), maximum load in flight (t=2.953, P=0.004), mean load in flight (t=2.575, P=0.011), insomnia (χ2=4.756, P=0.029) and smoking (χ2=7.977, P=0.005) were significantly different between the diseased group and the healthy group. Multivariate logistic regression showed that driving age [odds ratio (OR)=1.077, 95% confidence interval (CI) (1.025, 1.132), P=0.004], maximum load in flight [OR=1.279, 95%CI (1.109, 1.475), P=0.001], helmet weight [OR=1.516, 95%CI (1.056, 2.175), P=0.024], insomnia [OR=2.235, 95%CI (1.114, 4.483), P=0.024], and smoking [OR=2.527, 95%CI (1.255, 5.087), P=0.009] were risk factors for DDD. Conclusions The prevalence of DDD is high in pilots. High driving age, high maximum load in flight, high helmet weight, insomnia, and smoking may be independent risk factors for DDD.