Objective To observe the effect of Melittin on collagen type II (Col-II) expression of rat endplate chondrocytes (EPCs) induced by interleukin 1β (IL-1β). Methods Primary EPCs from the lumbar vertebra of 4-week-old Sprague Dawley rats were culturedin vitro and identified by morphological observation, toluidine blue staining and Col-II immunofluorescence staining. Then, MTT assay was used to determine the optimal concentration of IL-1 and Melittin. Next, EPCs at passage 3 were randomly divided into 4 groups: no treatment was done in group A as control group; the optimal concentration of IL-1β, Melittin, and both IL-1β and Melittin were used in groups B, C, and D respectively. The expression of Col-II was detected by Western blot after 48 hours intervention. Results Under inverted microscope, the first generation EPCs were polygonal; cell proliferation decreased after fifth generation, and cell morphology changed into fusiform. The acidic mucosubstance in the cytoplasm (such as Aggrecan) was stained dark blue by toluidine blue. After marking Col-II by immunofluorescence, the positive expression of cytoskeleton (green fluorescence) could be observed. MTT assay showed that IL-1β and Melittin could inhibit the EPCs in a dose-dependent manner after intervention of 24 and 48 hours, and the optimal concentrations of IL-1β and Melittin intervention were 10 ng/mL and 1.0 μg/mL respectively. Compared with group A, the expression of Col-II was significantly reduced in group B, and was significantly increased in group C by Western blot assay, but there was no significant difference between group D and group A. The Col-II expression levels of groups A, B, C, and D were 0.991±0.024, 0.474±0.127, 1.913±0.350, and 1.159±0.297 respectively, showing significant difference between the other groups (P<0.05) except between group A and group D (P>0.05). Conclusion Melittin has a protective effect on endplate cartilage, and the research results provide experimental basis for the prevention and treatment of spinal degenerative disease.
Objective To investigate the effect of collagen peptides from walleye pollock skin on the microstructure of osteoporosis model in ovariectomized rats, and to explore the feasibility of preventing and treating oste- oporosis. Methods Sixty adult Wistar female rats, weighing (250±10) g, were randomly divided into 5 groups (12 rats each group): normal group (group A), osteoporosis model group (group B), osteoporosis model+collagen peptides from walleye pollock skin prevention group (group C), osteoporosis model+low concentration of collagen peptides from walleye pollock skin treatment group (group D), and osteoporosis model+high concentration of collagen peptides from walleye pollock skin treatment group (group E). The rats in groups B, C, D, and E were removed bilateral ovarian to establish osteoporosis model. The rats in group C were treated with stomach perfusion of the collagen peptides from walleye pollock skin (1.0 g/kg) from 4 weeks after operation for 6 weeks; and the rats in groups D and E were treated with stomach perfusion of the collagen peptides from walleye pollock skin (0.5, 1.0 g/kg respectively) at 6 weeks after operation for 6 weeks. The rats in groups A and B were given equal volume of normal saline at the same time after operation. At 24 hours after the last administration, the femoral gray value of rats in groups A and B were measured by X-ray film; HE staining was performed on the proximal tibial bone of the left side in 4 groups; the histopathological changes of the bone were observed and the trabecular number (TN), mean trabecular plate thickness (MTPT), mean trabecular plate spacing (MTPS), trabecular bone volume (TBV), mean bone cortical thickness (MBCT) were measured; immunohistochemical staining was performed to observe the expression levels of caltitonin receptor (CTR) and interleukin 1 (IL-1). Results The femoral gray value of group B was significantly lower than that of group A (t=45.130, P=0.000), which indicated that the ovariectomized rat model was successfully prepared. Histological observation showed that TN, MTPS, TBV, and MBCT in groups A, C, and E were significantly different from those in group B (P<0.05). The histological parameters of bone tissue in group C were significantly different from those in groups D and E (P<0.05). TN, MTPS, TBV, and MBCT in group D were significantly different from those in group A (P<0.05); only MTPS in group E was significantly different from that in group A (P<0.05). MTPS, TBV, and MBCT in group E were significantly different from those in group D (P<0.05). The immunohistochemical staining showed that the levels of CTR and IL-1 in groups A, C, D, and E were lower than those in group B, in groups C and E were lower than in group D, showing significant differences (P<0.05). Conclusion Collagen peptides from walleye pollock skin can improve the bone microstructure of osteoporotic rats, and its mechanism may be related to the inhibition of CTR and IL-1 expression in bone tissue, but it has not been found to prevent osteoporosis.
Objective To investigate the effect and mechanism of miR-4287, a chondrogenesis associated microRNA, regulated the expression of aggrecanase-1 (a disintegrin and metalloproteinase with thrombospondin motif 4, ADAMTS4) in human chondrocytes. Methods First, the voluntarily donated normal and osteoarthritic knee articular cartilages were used to detect the expressions of miR-4287 and ADAMTS4 mRNA by real-time fluorescence quantitative PCR. Then, chondrocytes were isolated from knee articular cartilages. The effect of IL-1β on the expression of miR-4287 and ADAMTS4 mRNA was validated by the first generation of osteoarthritic chondrocytes. To confirm the influence of IL-1β signal pathways on the expression of miR-4287 and ADAMTS4 mRNA, osteoarthritic chondrocytes were pretreated with MAPK signal pathway inhibitor SP600125, NF-κB pathway inhibitor SN50, and finally stimulated with IL-1β. Chondro cytes were transfected with miR-4287 mimics and mimics negative control, inhibitors and inhibitors negative control respectively to value the effect of miR-4287 on ADAMTS4 expression. Luciferase reporter assay was used to verify the direct interaction between miR-4287 and putative site in the 3-untranslated region (3’UTR) of ADAMTS4 mRNA. Results Compared with normal knee articular cartilages, the miR-4287 expression was markedly diminished and conversely ADAMTS4 mRNA expression was raised in osteoarthritis cartilages (P<0.05). Stimulation with IL-1β led to a reduction in miR-4287 expression and upregulation in ADAMTS4 mRNA expression, showing significant difference when compared with the untreated groups (P<0.05). Pretreatment with IL-1β signal pathway inhibitors induced miR-4287 expression and attenuated ADAMTS4 mRNA expression in human chondrocytes, which were significantly different from that of unstimulated cells (P<0.05). ADAMTS4 mRNA and protein were suppressed by transfection with miR-4287 mimics (P<0.05) and elevated by transfection with miR-4287 inhibitors (P<0.05). As luciferase reporter assay showed, overexpression miR-4287 failed to alter the luciferase activity of a reporter construct containing either wild or mutant 3’UTR of ADAMTS4 mRNA (P>0.05). Conclusion miR-4287, a chondrogenesis associated microRNA, may play an important role in cartilage degeneration. miRNA-4287 is able to regulate ADAMTS4 expression in human chondrocytes, but not by means of directly targeted the ADAMTS4 mRNA 3’UTR. The exact mechanisms need to be further addressed.
ObjectiveTo observe effect of interferon-γ in preventing intestinal adhesion following abdominal surgery in rats.MethodsA total of 60 Wistar rats were selected, which were randomly divided into a sham operation (SO) group, model group, dexamethasone (DXMS) group, and interferon-γ group, then the interferon-γ group was randomly divided into a low, medium, and high concentrations subgroups. Except for the SO group, the laparotomies with file friction caecum were performed for all the other groups to establish the intestinal adhesion model. SO group and model group were intraperitoneally injected with saline for 4 mL/kg. The 10 mg/kg dexamethasone was injected into the abdominal cavity of rats in the DXMS group. The 7.5×104, 1.5×105, and 3.0×105 U/kg interferon-γ concentrations were injected into the abdominal cavity of rats in the low, medium, and high concentrations subgroups respectively. The Nair grading of cecum adhesion degree was assessed on the 8th day after the surgery, then the histopathological change was observed by the HE staining under the microscopy and the hydroxyproline content in the cecum tissue was detected.Results① The intestinal adhesion: Compared with the SO group, the intestinal adhesions occurred in all the other groups and the degrees of intestinal adhesions evaluated by the Nair grading were more significantly serious (P<0.05), which in the DXMS group and the medium and high concentrations of interferon-γ subgroups were significantly reduced (P<0.05) as compared with the model group, which in the high concentration of interferon-γ subgroup was significantly reduced (P<0.05) as compared with the DXMS group. ② The microscopic observation of histopathological results: Compared with the DXMS group, the high concentration of interferon-γ could effectively reduce the occurrence of fibrous tissue and inflammatory cell infiltration, the intestinal wall muscular layer structure was complete, a few inflammatory cells scattered in the infiltration. ③ The hydroxyproline content: The contents of hydroxyproline in the cecum tissue of the model group, DXMS group, and interferon-γ subgroups were significantly increased (P<0.05) as compared with the SO group, which of the DXMS group and medium and high concentrations of interferon-γ subgroups were significantly decreased (P<0.05) as compared with the model group, which of the high concentration of interferon-γ subgroup was significantly decreased (P<0.05) as compared with the DXMS group.ConclusionInterferon-γ has a preventive and therapeutic effect on postoperative intestinal adhesion and cecum injuries.
ObjectiveTo explore the effects of interleukin 10 (IL-10) gene modified bone marrow mesenchymal stem cells (BMSCs) on the expression of inflammatory cytokines and neuronal apoptosis in rats after cerebral ischemia reperfusion injury.MethodsBMSCs were cultured by whole bone marrow adherence screening method. The properties of BMSCs were identified by immunocytochemical methods. BMSCs at passage 3 were transfected with recombinant adenovirus IL-10 gene (AdIL-10-BMSCs). The model of middle cerebral artery occlusion was made in 40 adult male Sprague Dawley rats by thread embolism method. The rats were randomly divided into 4 groups (n=10). At 3 hours after modelling, the rats of groups A, B, C, and D received tail intravenous injection of 1 mL L-DMEM medium containing 10% FBS, 61.78 ng IL-10, 1 mL BMSCs suspension (2×106 cells/mL), and 1 mL AdIL-10-BMSCs cell suspension (2×106 cells/mL), respectively. The cells were labelled with BrdU before cell transplantation in groups C and D. At 7 days after reperfusion, the brain tissue was harvested to detect the expression of OX42 by immunohistochemical assay, to determine the concentration of tumor necrosis factor α (TNF-α) and IL-1β by ELISA, and to detect the apoptosis by TUNEL assay. BrdU labelled cells were observed by immunofluorescence staining in groups C and D.ResultsBrdU labelled positive cells with green fluorescence were observed in the brain tissue of groups C and D, which mainly distributed in the striatum, cerebral cortex, and subcortex around the infarction area. The number of OX42 positive cells was significantly less in groups B, C, and D than group A (P<0.05), and in group D than groups B and C (P<0.05). Compared with the other 3 groups, the contents of TNF-α and IL-1β significantly decreased in group D (P<0.05). TUNEL assay showed that the apoptotic cells (TUNEL positive cells) were mainly seen in the striatum and fronto parietal subcortical tissues (equivalent to ischemic penumbra). The number of TUNEL positive cells in group D was significantly less than that in groups A, B, and C (P<0.05).ConclusionAdIL-10-BMSCs can inhibit secretion of TNF-α and IL-1β from microglial cells and inhibit the nerve cell apoptosis around infarct brain tissue, which might contribute to its protective role upon cerebral ischemia reperfusion injury.