Effects of long non-coding RNA insulin-like growth factor 2-AS on osteoporotic fracture in rats and its mechanism
Objective To investigate the effects of long non-coding RNA(lncRNA)insulin-like growth factor 2(IGF2)-AS on fracture healing in osteoporotic rats and its molecular mechanism.Methods Totally,30 SD rats were divided into control group,fracture group and lncRNA IGF2-AS group according to the random number table method.Rat models of osteoporosis were established by ovariectomy in the frac-ture group and lncRNA IGF2-AS group,and tibial fracture models were established at 3rd month after ovar-iectomy in the control group.Rats in the lncRNA IGF2-AS group were injected with adeno-associated virus overexpressing lncRNA IGF2-AS in the tibia at 2nd month after ovariectomy,and those in the control group and fracture group were injected with empty adeno-associated virus.After 4 weeks of modeling,the fracture healing and bone mineral density changes of the three groups were observed.The expression levels of bone morphogenetic protein-2,osteoblast-specific protein(Osterix)and osteoblast differentiation factor(ODF)in the callus tissue were analyzed by Western blotting.The biomechanical changes of the tibia of the three groups were analyzed by biomechanics.The changes of mineralized width,mineralized volume,osteoid width and volume were analyzed by bone tissue morphometry.The measurement data between groups were analyzed by one-way analysis of variance.Results The tibia of rats in the control group was intact without fracture.The fracture line of rats in the fracture group was obvious,and there was a small amount of sparse callus at the fracture end.The callus outside the fracture end of rats in the lncRNA IGF2-AS group was dense,and the fracture line was blurred.The tibial bone mineral density of rats in lncRNA IGF2-AS group[(0.087±0.003)g/cm2]was significantly higher than that in the fracture group[(0.072± 0.008)g/cm2,t=5.486,P＜0.05].The expression levels of bone morphogenetic protein-2,osteoblast-specific protein(Osterix)and osteoblast differentiation factor(ODF)in rats in lncRNA IGF2-AS group(1.50±0.14,1.47±0.20,1.61±0.11)were significantly higher than those in the fracture group(0.64±0.11,0.53±0.09,0.73±0.10,t=15.310,13.610,19.480,P＜0.05).The maximum load,shear strain and elastic modulus of rats in lncRNA IGF2-AS group[(32.53±2.65)N,(60.37± 2.97)Kn/mm2,(182.89±15.06)GPa]were significantly higher than those in the fracture group[(27.32±3.35)N,(48.06±4.97)Kn/mm2,(148.97±14.75)GPa,t=3.886,6.727,5.088,P＜0.05].The relative volume of bone trabecula,the average thickness of bone trabecula and the mineraliza-tion delay time of rats in lncRNA IGF2-AS group[(26.10±2.44)％,(84.61±6.08)μm,(2.64± 0.11)d]were significantly higher than those in the fracture group[(22.07±2.26)％,(76.63± 3.66)μm,(2.21±0.15)d,t=3.858,3.673,7.349,P＜0.05].Conclusion LncRNA IGF2-AS can significantly promote the expression of bone formation related proteins in rats with osteoporotic fracture,improve bone healing,and increase bone density.
Long non-coding RNAInsulin-like growth factorOsteoporosis fracturesFrac-ture healingBiomechanics
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