过表达lncRNA HAGLR促胫骨骨折大鼠骨髓间充质干细胞成骨分化的机制研究OACSTPCD

Objective To study the expression of long noncoding RNA Homeobox D gene cluster antisense growth-associated long noncoding RNA(lncRNA HAGLR)and its downstream target genes in osteoporosis(OP)-tibial fracture(TF)rats,and to explore the effect and mechanism of lncRNA HAGLR on osteogenic differentiation of rat bone marrow mesenchymal stem cells(MSCs).Methods A total of 30 SD female rats were randomly divided into the sham group,the OP group and the OP-TF group,with 10 rats in each group.Serum alkaline phosphatase(ALP)and tartrate-resistant acid phosphatase(TRAP)levels of rats were detected by ELISA.Rats MSC cell line R7500 was induced by osteogenic differentiation induction medium and divided into the MSC group and the Osteogenic-MSC group.R7500 was individually transfected with pcDNA-HAGLR,pcDNA-NC,miR-19a-3p mimic,mimic negative control(NC mimic),miR-19a-3p inhibitor and negative control of miR-19a-3p inhibitor(NC inhibitor),and divided into corresponding groups.The dual luciferase gene report experiment was used to verify the targeting relationship between lncRNA HAGLR and miR-19a-3p and bone morphogenetic protein 2(BMP2)and miR-19a-3p.The expressions of lncRNA HAGLR and miR-19a-3p in each group were detected by qRT-PCR.The expressions of BMP2,ALP,collagen Ⅰ(COL-Ⅰ),osteocalcin(OCN),and osteopontin(OPN)were detected by Western blot.ALP staining and AR staining were used to detect the osteogenic differentiation ability of MSC.Results The serum ALP and TRAP levels in the OP group and the OP-TF group were higher than those in the sham group,and the differences were statistically significant(P<0.05).There was no significant difference in the expression levels of lncRNA HAGLR,miR-19a-3p or BMP2 of tibia tissue between the OP group and the sham group(P>0.05),while the expression levels of lncRNA HAGLR and BMP2 of tibia tissue in the OP-TF group were significantly lower than those in the sham group and the OP group(P<0.05),the expression level of miR-19a-3p of tibia tissue in the OP-TF group was higher than those in the sham group and the OP group(P<0.05).Compared with the MSC group,the expression level of lncRNA HAGLR in the Osteogenic-MSC group was significantly increased(P<0.05),while the expression of miR-19a-3p was decreased(P<0.05).The dual luciferase gene report experiment verified that lncRNA HAGLR has a targeting relationship with miR-19a-3p,and miR-19a-3p has a targeting relationship with BMP2.The expression level of miR-19a-3p in the pcDNA-HAGLR group was lower than that in the pcDNA-NC group(P<0.05).There was no significant difference in the expression level of lncRNA HAGLR between the miR-19a-3p mimic group and the NC mimic group(P>0.05).Compared with the NC mimic group,the expression level of BMP2 protein in the miR-19a-3p mimic group was decreased(P<0.05),while the expression level of miR-19a-3p was increased(P<0.05).The cells in the pcDNA-HAGLR group had stronger osteogenic differentiation ability and higher ALP activity than those in the pcDNA-NC group(P<0.05).The cells in the miR-19a-3p inhibitor group had stronger osteogenic differentiation ability and higher ALP activity than those in the NC inhibitor group(P<0.05).Conclusion The expression of lncRNA HAGLR and BMP2 is decreased and the expression of miR-19a-3p is increased in rats with tibial fracture.Overexpression of lncRNA HAGLR promotes osteogenic differentiation of rat MSCs by targeting the miR-19a-3p/BMP2 axis.