Abstract: BACKGROUND: The imbalance between proliferation and apoptosis of chondrocytes plays an important role in the occurrence and development of osteoarthritis. Previous studies have found that hsa-miR-3202 is involved in regulating the proliferation and apoptosis of various cells. However, no studies have explored the correlation between hsa-miR-3202 and osteoarthritis.
OBJECTIVE: To investigate the expression of hsa-miR-3202 in osteoarthritic chondrocytes and its effect on the proliferation and apoptosis of chondrocytes.
METHODS: (1) MicroRNAs differentially expressed in osteoarthritic chondrocytes were screened by biogenic analysis. Based on the current research situation at home and abroad, hsa-miR-3202 was selected for follow-up studies, and its target genes were predicted by gene ontology (GO) functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. (2) Human normal chondrocyte cell lines C28/I2 in logarithmic growth phase were selected and randomly divided into four groups for culture: in normal group, cells were cultured in normal medium for 24 hours, the medium was then changed to normal medium for another 6 hours of culture, and changed to normal medium for subsequent culture; in lipopolysaccharide group, cells were cultured in lipopolysaccharide-containing medium for 24 hours, the medium was then changed to normal medium for another 6 hours, and changed to normal medium for subsequent culture; in lipopolysaccharide+NC group, cells were cultured in lipopolysaccharide-containing medium for 24 hours, and then transfected with has-miR-3202 mimics control for 6 hours, and the medium was change to normal medium for subsequent culture; in lipopolysaccharide+hsa-miR-3202 mimics group, cells were cultured in lipopolysaccharide-containing medium for 24 hours and then transfected with has-miR-3202 mimics for 6 hours, and the medium was changed to normal medium for subsequent culture. After further 48 hours of culture, the expression level of hsa-miR-3202 was detected by fluorescence quantitative PCR and cell apoptosis was detected by flow cytometry. After further culture of 0-72 hours, cell proliferation activity was detected by cell counting kit-8.
RESULTS AND CONCLUSION: Bioinformatics analysis results indicated that hsa-miR-3202 was significantly down-regulated in osteoarthritic chondrocytes. GO functional enrichment and KEGG pathway enrichment showed that the function of hsa-miR-3202 target gene was closely related to cell growth and apoptosis. The results of in vitro cell experiments showed that compared with the normal group, the expression level of hsa-miR-3202 and proliferation ability of chondrocytes were significantly decreased in the lipopolysaccharide group (P < 0.05), while the apoptotic rate was significantly increased (P < 0.05). Compared with the lipopolysaccharide group, the expression level of hsa-miR-3202 and proliferation ability of chondrocytes were significantly increased in the lipopolysaccharide+hsa-miR-3202 mimics group (P < 0.05), while the apoptotic rate was significantly decreased (P < 0.05). To conclude, the expression of hsa-miR-3202 is down-regulated in osteoarthritic chondrocytes to inhibit cell proliferation and promote cell apoptosis, thus affecting the occurrence and development of osteoarthritis. 

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

Key words: has-miR-3202, osteoarthritis, bioinformatics, chondrocyte, inflammation, cell proliferation, cell apoptosis, older adults