| Objective To investigate the effects of GLP-1 analog liraglutide on glucocorticoid osteoporosis rats,the changes of autophagy,oxidative stress levels and possible mechanisms.Methods(1)Thirty healthy 8-week-old male SD rats were selected and randomly divided into three groups after one week of adaptive feeding: normal control group,dexamethasone group,and dexamethasone + liraglutide intervention group,each group Ten.The control group was given a daily intramuscular injection of 0.1 m L of physiological saline;dexamethasone group was configured as a 0.1 m L dexamethasone solution twice a week by intramuscular injection at a dose of 1 mg / kg;dexamethasone solution injections,liraglutide was given a subcutaneous injection of200 ?g / kg daily for 12 weeks.(2)Collect bilateral femurs after sacrificing the rats,and select the left distal femur by Micro-CT to detect the bone mineral density(BMD)of the distal femoral region of interest.The bone volume / tissue volume,BV / TV)Trabecular number(Tb.N)Trabecular thickness(Tb.Th)Trabecular separation(Tb.Sp)and trabecular connection density(connectivity density,Conn.D)parameter.(3)the contents of Reactive Oxygen Species(ROS),Superoxide dismutase(SOD)and Malonaldehyde(MDA)in bone tissue were detected by ELISA.(4)Western Blot(WB)to detect the expression levels of autophagy-specific genes Beclin-1,Atg5,p62 / SQSTM1 W and Map1-LC3-IIResults(1)Liraglutide can improve glucocorticoid osteoporosis: compared with the control group,the bone density of the metaphysis of the distal femur in the dexamethasone group(187.57 ± 44.69 mg / cm3 vs 282.29 ± 49.02 mg / cm3)Significantly reduced(P<0.05),the trabecular volume ratio(0.20 ± 0.08 vs 0.32 ± 0.08)was significantly reduced(P<0.05),and the number of sacral trabeculae(3.32 ± 0.15 mm-1 vs 4.94 ±0.15 mm-1)was significantly reduced Decrease(P<0.05),the thickness of trabecular bone(0.07 ± 0.01 mm vs 0.20 ± 0.06 mm)was significantly reduced(P<0.05),and the distance between trabecular bones(0.30 ± 0.01 mm vs 0.20 ± 0.01 mm)was significantly increased(P<0.05),the trabecular bone connection density(68.75 ±11.28 mm-3 vs 132.38 ± 15.08 mm-3)decreased significantly(P<0.05).Compared with the dexamethasone group,the bone density(280.16 ± 66.08 mg / cm3 vs 187.57 ±44.69 mg / cm3)of the distal femur of the liraglutide-treated group increased significantly(P<0.05),and the bone trabecular volume ratio(0.24 ± 0.07 vs 0.20 ±0.08)The difference was not statistically significant,the number of trabecular bones(4.19 mm-1 ± 1.13 vs 3.32 ± 0.15 mm-1)The difference was not statistically significant,and the thickness of trabecular bones(0.19 ± 0.04 mm vs 0.07 ± 0.01 mm)was significantly increased(P<0.05),the trabecular bone spacing(0.24 ± 0.09 mm vs 0.30± 0.01 mm)was not significantly different,and the trabecular bone connection density was(119.28 ± 25.27 mm-3 vs 68.75 ± 11.28)mm-3)increased significantly(P<0.05).(2)Liraglutide can reduce the level of oxidative stress in bone tissue of glucocorticoid-induced osteoporosis rats:Compared with the control group,ROS(41378.67 ± 5 252.80 U / mg vs 22 486.33 ± 3 430.40 U / mg)in dexamethasone group showed a significant increase(P<0.05).MDA(6.60 ± 0.84 fluorescence intensity vs3.42 ± 0.91 fluorescence intensity)increased significantly(P<0.05),and the antioxidant enzyme SOD(4.56 ± 0.88 nmol / mg vs 14.25 ± 2.29 nmol / mg)decreased significantly(P<0.05).Compared with the dexamethasone group,the ROS(39 781.67± 4 312.99 U / mg vs 41 378.67 ± 5 252.80 U / mg)in the bone tissue of the liraglutide intervention group was significantly reduced(P<0.05),and the MDA(4.85 ± 1.16 fluorescence intensity)vs 6.60 ± 0.84 fluorescence intensity)decreased significantly(P<0.05),and the antioxidant enzyme SOD(8.26 ± 1.57 nmol / mg vs 4.56 ± 0.88 nmol /mg)significantly increased(P<0.05).(3)Liraglutide can reduce the autophagy level of bone tissue in glucocorticoid osteoporotic rats: Compared with the control group,the expression levels of autophagy-related genes Beclin-1,Atg5 and Map1-LC3-II in the dexamethasone group increased,and the expression level of p62 / SQSTM1 W protein decreased slightly(P<0.05).Compared with the dexamethasone group,the expression levels of autophagy-related proteins Beclin-1,Atg5,and Map1-LC3-II in the liraglutide-treated group decreased significantly,and the expression levels of p62 / SQSTM1 W protein increased slightly(P<0.05).Conclusions Liraglutide can improve osteoporosis caused by glucocorticoids,and its mechanism may be related to regulating some autophagy and improving oxidative stress. |
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