基于SLC7A11/GPX4通路探讨淫羊藿苷对绝经后骨质疏松症大鼠的影响OA

Objective:To explore the mechanism of Icariin(ICA)regulating the axis of solute carrier family 7 member 11(SLC7A11)/glutathione peroxidase 4(GPX4)to improve osteoporosis in ovariectomized rats.Methods:Totally 36 8-week-old healthy female SD rats were randomly divided into Sham surgery(Sham)group,Bilateral ovariectomy(OVX)group,Estradiol valerate(E2V)group and Low-dose icariin group(ICA-L group),Middle-dose icariin group(ICA-M group)and High-dose icariin group(ICA-H group),with 6 rats in each group.The rat model of postmenopausal osteoporosis was established by bilateral ovariectomy(Sham group only removed the fat near the ovary and performed abdominal incision suture operation).Gastric lavage was given daily for 8 weeks after operation.Sham group and OVX group were given normal saline(10 mL/kg)daily.E2V group was given estradiol valerate(0.6 mg/kg).The ICA-L group,ICA-M group and ICA-H group were given low,medium and high doses of ICA(50,100 and 200 mg/kg)respectively.After the experiment,the femoral bone microstructure,bone mineral density(BMD),relative bone volume(BV/TV),trabecular number(Tb.N)and trabecular separation(Tb.Sp)were measured.Enzyme linked immunosorbent assay(ELISA)was used to detect serum osteoprotegerin(OPG),receptor activator of nuclear factor-KB ligand(RANKL)and tartrate-resistant acid phosphatase 5b(TRACP-5b).Serum levels of superoxide dismutase(SOD),malondialdehyde(MDA)and Ferrous ion(Fe2+)were detected by the kit.The expression levels of ferritin heavy chain 1(FTH1),SLC7A11 and GPX4 in rat lumbar spine were detected by Western blotting.Quantitative real-time reverse transcription polymerase chain reactio(qRT-PCR)was used to detect the expression levels of SLC7A11 mRNA and GPX4 mRNA in rat lumbar tissues.Results:In OVX group,the femur of rats showed significant bone microstructure degradation,which was manifested by the decrease of trabecular number,accompanied by the disorder of trabecular network arrangement,characteristic trabecular structure atrophy and irregular morphological changes.The trabecular density of ICA-L group was slightly improved compared with OVX group.The trabecular structure of femur in E2V group,ICA-M group and ICA-H group was arranged in order.BMD,BV/TV and Tb.N in OVX group were lower than those in Sham group(P＜0.01),while Tb.Sp was higher than that in Sham group(P＜0.01).The E2V group,ICA-M group and ICA-H group showed higher BMD,BV/TV and Tb.N than OVX group(P＜0.05 or P＜0.01),while lower Tb.Sp than OVX group(P＜0.01).The BMD in ICA-L group was higher than that in OVX group(P＜0.05).The contents of OPG,OPG/RANKL and SOD in serum of OVX group were lower than those in Sham group(P＜0.01),while the contents of RANKL,TRACP5b,MDA and Fe2+were higher than those in Sham group(P＜0.01).The contents of OPG,OPG/RANKL and SOD in serum of E2V group were higher than those of OVX group(P＜0.05 or P＜0.01),while the contents of RANKL,TRACP5b,MDA and Fe2+were lower than those of OVX group(P＜0.01).The content of OPG in serum of ICA-H group was higher than that in OVX group(P＜0.01).Serum SOD content and OPG/RANKL in ICA-L group,ICA-M group and ICA-H group were higher than those in OVX group(P＜0.01),while the contents of RANKL,TRACP5b,MDA and Fe2+were lower than those in OVX group(P＜0.01).The relative expression of FTH1,SLC7A11 and GPX4 protein in OVX group was lower than that in Sham group(P＜0.01).The relative expressions of FTH1,SLC7A11 and GPX4 proteins in lumbar vertebrae of E2V group and ICA-H group were higher than those in OVX group(P＜0.01).The relative expression of SLC7A11 and GPX4 protein in lumbar vertebrae of rats in ICA-M group was higher than that in OVX group(P＜0.01).The relative expression of GPX4 protein in the lumbar vertebrae of rats in ICA-L group was higher than that in OVX group(P＜0.05).The relative expressions of SLC7A11 mRNA and GPX4 mRNA in the lumbar vertebrae of OVX group were lower than those in Sham group(P＜0.01).The relative expressions of SLC7A11 mRNA and GPX4 mRNA in lumbar vertebrae of E2V group,ICA-L group,ICA-M group and ICA-H group were higher than those in OVX group(P＜0.01).Conclusion:Icariin can decrease osteoclast activity in OVX rats,inhibit bone resorption,increase antioxidant capacity,reduce lipid peroxidation damage,reduce free Fe2+accumulation,ultimately reduce bone resorption,promote bone formation,repair trabecular structure and play an anti-osteoporosis role through the up-regulation mechanism of SLC7A11/GPX4 axis.