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BACKGROUND: Endoplasmic reticulum (ER) stress has been proved to be related to the occurrence of diabetes, dilated cardiomyopathy and neurodegenerative diseases. Indeed, it is closely associated with osteoarthritis. OBJECTIVE: To explore the effect of ER stress on the chondrocyte viability as well as the occurrence and development of osteoarthritis in rats. METHODS: Rat chondrocytes were isolated and cultured, and the ER stress in the rat chondrocytes was by 10 mg/L tunicamycin. The expression levels of ER stress markers C/EBP-homologous protein and 78 kDa glucose-regulated protein were detected by western blot assay, and the proliferation and apoptosis of chondrocytes were detected by cell counting kit-8 assay and AnnexinV-FITC flow cytometry, respectively. In the in vivo experiment, 15 Sprague-Dawley rats were selected and subjected to anterior cruciate ligament transection and medial meniscectomy to establish an animal model of osteoarthritis. Tunicamycin, tauroursodeoxycholic acid and PBS (blank control group) were respectively injected into the articular cavity, and then the progression of osteoarthritis was assessed by hematoxylin-eosin staining at 4 weeks after treatment. RESULTS AND CONCLUSION: After addition of tunicamycin, the expression levels of C/EBP-homologous protein and 78 kDa glucose-regulated protein were significantly upregulated, the viability of chondrocytes was decreased gradually, while the apoptotic rate was increased significantly. Results from gross observation and hematoxylin-eosin staining suggested that tunicamycin promoted the progression of osteoarthritis and tauroursodeoxycholic acid delayed the deterioration of cartilage in the rats. These findings indicate that ER stress results in the decreased chondrocyte viability and increased apoptosis, which may be an important pathogenesis of osteoarthritis. Additionally, tauroursodeoxycholic acid can effectively alleviate osteoarthritis induced by ER stress.
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Objective:To screen the new candidate molecules interacting with protein kinase Wee1B by yeast two hybrid system, and to analyze their interaction with Wee1B in the early stage of mouse fertilized eggs by bioinformatics.Methods:The plasmid pcDNA3.1/V5-His-TOPO-Wee1B wild type encoding mouse Wee1B gene was used as template to construct bait plasmid pGBKT7 Wee1B and the bait plasmid pGBKT7-Wee1B was transformed into yeast competent cells at SD/Trp (SDO),SD/Trp/X-α-Gal (SDO/X)and SD/Trp/X α Gal/AbA plates (SDO/X/A)plates to detect the toxicity and self-activation ability of yeast and its expression in yeast using Western blotting method.The yeast cells containing pGBKT7-Wee1B were fused with human ovary cDNA library, the yeast plasmid transformation of Escherichia coli positive clones were sequenced after identified by yeast transformation.BLAST analysis was carried out in GenBank,and its effect on the development of mouse fertilized eggs was deduced according to the gene annotation.Results:The double enzyme digestion analysis and sequencing analysis results showed that the pGBKT7-Wee1B bait plasmid was successfully constructed.The plasmid was transformed into the yeast,and there were no clones in the SDO/X/A plates.The pGBKT7-Wee1B and pGBKT7 empty vectors were transformed into the yeast,the bacteria were inoculated on the SDO plates,and the clones were uniformly grown on the two SDO plates.The positive clones were picked and expanded in culture,the protein was extracted and Western blotting showed that pGBKT7 Wee1B was expressed in the yeast.The bait plasmids were fused with human ovary cDNA library and the positive clones inserted into the fragment were identified by PCR. Nine proteins which interacted with Wee1B protein kinase were screened out by sequencing and blast analysis,and the proteins which could be closely related to the development of mouse oocytes and the development of fertilized eggs were analyzed by bioinformatics analysis.Conclusion:Using the yeast two hybrid system from human ovary cDNA library,nine interacting proteins with Wee1B protein kinase are screened and these screened proteins may regulate mouse oocyte maturation and early embryo development through interacting with Wee1B.
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Objective:To investigate whether endogenous hydrogen sulfide (H2 S)was involved in the pathogenesis of osteoarthritis (OA)and its underlying mechanism,to detect H2 S and its synthases ex-pression in knee cartilage in patients diagnosed with different severity of OA,and to explore the transcrip-tion and expression of gene MMP-13 in chondrocytes treated with IL-1βor H2S.Methods:Synovial fluids of the in-patients with different severity of OA hospitalized in Peking University First Hospital were collected for measurement of H2 S content using methylene blue assay.Articular cartilages of the patients who underwent knee arthroplasty were collected for the cell culture of relatively normal chondrocytes.The chondrocytes were cultured to the P3 generation and H2 S molecular probes were used for detection of endogenous H2 S generation in the chondrocytes.Immunocytochemistry was used to detect the localization of H2 S synthases including cystathionine β-synthase (CBS),cystathionine-γ-lyase (CSE),and mercap-topyruvate sulfurtransferase (MPST)in OA chondrocytes.Western blot was used to quantify the protein expressions of CSE,MPST,and CBS in cartilage tissues of the patients who were diagnosed with OA and underwent knee arthroplasty.The relatively normal human chondrocytes were cultured to passage 3 and then divided into 4 groups for different treatments:(1 )the normal control group,no reagent was added;(2)the IL-1βgroup,5 μg/L of IL-1βwas added;(3)the IL-1β+H2S group,200 μmol/L of NaHS was added 30 min before adding 5 μg/L of IL-1β;(4)the H2 S group,200 μmol/L of NaHS was added. The transcription and expression of gene MMP-13 in chondrocytes of each group were determined with Real-time PCR and Western blot,respectively.And the total NF-κB p65 and phosphorylated NF-κB p65 in chondrocytes were detected with Western blot.Results:The content of H2 S in the synovial fluid of degenerative knee was (14.3 ±3.3)μmol/L.Expressions of endogenous H2 S and its synthases including CBS,CSE and MPST were present in the cytoplasm of chondrocytes.CSE protein expression in Grade 3 (defined by outerbridge grading)cartilage tissues was significantly increased as compared with that of Grade 1 cartilage tissues (1.67 ±0.09 vs.1.26 ±0.11,P<0.05).However,no significant difference of CBS or MPST expression among the different groups was observed.The expression of MMP-13 protein in the IL-1βgroup was significantly higher than that in the normal chondrocytes (1 .87 ±0.67 vs.0.22 ± 0.10,P<0.05 ),and that in the IL-1β+H2 S group was significantly decreased than that in the IL-1βgroup (0.55 ±0.11 vs.1.87 ±0.67,P<0.05),and that in the H2S group had no significant difference compared with that in the normal control group.The transcription of MMP-13 protein in the IL-1βgroup was significantly higher than that in the normal chondrocytes (31.40 ±0.31 vs.1.00 ±0.00,P<0.05), and that in the IL-1β+H2 S group was significantly decreased than that in the IL-1βgroup (24.41 ± 1.28 vs.31.40 ±0.31,P<0.05),and that in the H2S group had no significant difference compared with that in the normal control group.The total NF-κB p65 in the IL-1βgroup was significantly higher than that in the normal chondrocytes (2.13 ±0.08 vs.0.73 ±0.08,P<0.05),and that in the IL-1β+H2S group was significantly decreased than that in the IL-1βgroup (1 .24 ±0.13 vs.2.13 ±0.08,P<0.05 ),and that in the H2 S group had no significant difference compared with that in the normal control group.The phosphorylated NF-κB p65 in IL-1βgroup was significantly higher than that in the normal chondrocytes (1.30 ±0.13 vs.0.19 ±0.04,P<0.05),and that in IL-1β+H2S group was significantly decreased than that in the IL-1βgroup (0.92 ±0.26 vs.1.30 ±0.13,P<0.05),and that in the H2S group had no significant difference compared with that in the normal control group.Conclusion:H2 S affected the cartilage degeneration by partly inhibiting the degradation of extracellular matrix.
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Objective:To investigate the efficacy of single time intra-articular different concentration of allogeneic bone marrow mesenchymal stem cells ( BM-MSCs ) injection in the treatment of Sprague-Dawley ( SD) rat model of osteoarthritis ( OA) .Methods: In the study, 32 SD rats were equally ran-domized into 4 groups:control group, high concentration group (1 ×107/mL BM-MSCs), low concentra-tion group (5 ×106/mL BM-MSCs) and high vs.low concentration group.The two knees of each rat were set up to a pair.The induction of OA was performed surgically randomly at one side in model group, and bilaterally in the other groups, which were through anterior cruciate ligament transaction ( ACLT) and medial meniscus excising.After the operation, the SD rats were allowed free movement.Four weeks later, different concentrations of allogeneic BM-MSCs isolated from the SD rats, expanded in vitro and suspended in phosphate buffered solution( PBS) were delivered in the articular cavity of both knees;PBS was used as the control.After injection, we excised the femoral nerve and sciatic nerve to disuse the low limb.The cartilage histological sections of knees were scored by Mankin scoring system to assess the se-verity of the pathology.mRNA of collagen Ⅱwas detected by real time polymerase chain reaction ( RT-PCR) .eGFP was detected by fluorescence microscope.Assessments were carried out 4 weeks after the operation in model group, and 3 weeks after injection in the other groups.Results:Mankin scores of the BM-MSCs side and control side were 6.60 ±0.40 vs.10.00 ±0.32 in low concentration group ( P0.05).mRNA expression of collagen Ⅱ of the BM-MSCs side in low concentration group was 106%±1%in contrast to the control side.As in high concentration group it was 108%±1%, and 102%±1%in high vs. low concentra-tion group.Labeled BM-MSCs were detected unexpectedly in the synovial membrane but not in cartilage tissue three weeks from injection.Conclusion:BM-MSCs could promote cartilage repair and inhibit OA progression through a trophic mechanism.There was no difference between the two concentrations.