RESUMO
Objective To detect the apoptosis of femoral head cartilage cells and to observe the expression of apoptosis-related proteins in the tissues of the femoral head,as well as to explore the main pathway for regulating the apoptosis in steroid induced by juvenile rabbit models with avascular necrosis of femoral head.Methods The models with avascular necrosis of the femoral head and the control group model were made in New Zealand infancy albino rabbits induced by glucocorticoid(GC).The immunohistochemical method was used to detect the expressions of Caspase3,Caspase-8,apoptosis protease activating factor-1 (apaf-1),calpain-1 in the femoral heads.Results 1.The integrated optical density(IOD) values of Caspase-3 in GC-induced subgroup,the subgroup that was not induced by GC and control group were 25 142.72 ± 21 528.48,2 069.63 ± 1 096.96 and 301.80 ± 99.66,respectively.The IOD values of Caspase-8 in GC-induced subgroup,the subgroup respectively and the control group were 24 942.63 ± 18 942.99,2 016.31 ± 1 518.70,236.85 ±97.94,respectively.The IOD values of apaf-1 in GC-induced subgroup,the subgroup that was not induced by GC and the control group were 8 5 14.23 ± 6 384.20,1 118.49 ± 1 360.59,95.13 ± 38.05,respectively.The IOD values of calpain-1 in GC-induccd subgroup,the subgroup that was not induced by GC and control group were 9 636.71 ± 9 123.81,1 881.10 ± 3 277.86,126.71 ± 47.35,respectively.The IOD value differences of the Caspase-3 between GC-induced subgroup and the subgroup that was not induced by GC,the control group were extremely significant (H =l 1.470,23.996,P ＜ 0.01).The IOD value differences of the Caspase-8,apaf-1,calpain-1 between GC-induced subgroup and the control group were extremely significant (H =22.178,22.808,13.553,P ＜ 0.01).2.The linear regression analysis results showed that under the joint action of Caspase-8,apaf-1,calpain-1,only the Caspase-8 could significantly predict Caspase-3,and its regression equation regression got significant effect and could explain 40.3％ of the variance;while the regression effects of the apaf-1 and calpain-1 to Caspase-3 were not significant.Conclusion Death receptor pathway might play a major regulation role in the apoptotic process of avascular necrosis.
RESUMO
Objective To detect the expression of glucocorticoid receptor(GR) in juvenile rabbit modal of avascular necrosis of the femoral head,and explore the possible etiology of avascular necrosis of the femoral head in children.Methods Sixty New Zealand albino rabbits(50％ female and 50％ male),2 months old,body weight 1.4-1.7 kg,were randomly divided into 2 groups:steroid injection group (SIG) and control group(CG).The SIG(n =48):Prednisolone acetate of 7.5 mg/kg was injected into each rabbit twice a week for 8 weeks.The CG(n =12):9 g/L saline of 0.3 mL/kg was injected into each rabbit twice a week for 8 weeks.The immunohistochemistry and image analysis were used to detect the expression of GR.The SIG was divided into disease group(DG) and non-disease group(NDG).The expressions of GR were compared among DG,NDG and CG.Results In the 8th week after the first injection in SIG,31 out of 48 rabbits survived,and 7 out of 31 rabbits(22.85％) developed femoral head avascular necrosis.GR expression in DG was 100.00％ (7/7 cases),while in NDG and CG they were 20.83％ (5/24 cases) and 16.67％ (1/6 cases).Significant difference was found between DG and NDG/CG(all P ＜ 0.01),but not between NDG and CG.GR expression density in femoral cartilage in DG was higher than in NDG and CG(all P ＜ 0.01).GR expression IOD in femoral cartilage was 7942.21 ± 1886.94,but in DG and NDG they were extremely low or undetectable,which were 627.56 ± 281.85 and 571.48 ± 260.22,separately,and there was significant difference (all P ＜ 0.01).Conclusions Simple gluteal injection of glucocorticoid can lead to juvenile rabbits avascular necrosis of femoral head.GC and GR might play an important role in the onset and development of avascular necrosis of femoral head in juvenile rabbits.