Effects Of Castration On Ischemic Muscles In The Hind Limbs Of Rats

ObjectiveTo investigate the influence of castration on the free calcium concentration of mitochondria and the macrophage infiltration in the ischemic muscles of rat hindlimbs, and to clarify the role of androgen in ischemic muscles of rat hindlimbs.MethodsNinety-six male Wistar rats(200±50g) were distributed to normal control group, ischemic hindlimb group(undertaken ischemic hindlimb only),castration group (undertaken castration only) and castration plus ischemia group(2 weeks after castration,undertaken ischemic hindlimb) randomly,24 in each group.Then the 24 rats in each group were randomly divided into 4 sub-groups,after finishing the hindlimb ischemic model by microsurgical technique.The rats were sacrificed at 1,2,3 and 4 weeks after the operation respectively.Blood samples were taken for determination of serum testosterone;extensor digitorum longus,soleus and gastrocnemius muscle were harvested for the further research.The free calcium concentration of mitochondria and the CD68 stain by immunohistochemical method in the ischemic muscles were detected to investigate the damage of muscles and the macrophage infiltration in the ischemic muscles.ResultsThe serum testosterone declined from 24 hours after the castration significantly (P＜0.05),and maintained at low level with time.The free calcium concentration of the mitochondria in the ischemic muscles was significantly increased in each ischemic hindlimb group(P＜0.05),and reached the peak at one week after surgery.Then the concentration declined at two weeks,and returned to the level as the pre-operative at four weeks after surgery.The castration plus ischemia group showed the same trends as the ischemic hindlimb group.There was significant difference between ischemic hindlimb group and castration group in the extensor digitorum longus muscles at 1,2 weeks after surgery,but there was no significant difference in soleus at 1,2,3 weeks and in gastrocnemius at 2,3 weeks after surgery,between ischemic hindlimb group and castration group(P＜0.05).There was no difference in the free calcium concentration of mitochondria of ischemic muscles between the castration plus ischemia group and ischemic hindlimb group in 4 weeks after surgery(P＞0.05).There was no significant difference between castration group and normal control group in each muscle on mitochondrial free calcium concentration(P＞0.05).Macrophage infiltration was obviously observed in the soleus muscle of castration plus ischemia group at 1,2 weeks after surgery.ConclusionCastration promoted the damage effects in the ischemic muscles of rat hindlimbs. Soleus,as the typical muscle of slow twitch fibers,shows poor resistance to ischemia and hypoxia.