| ObjectiveBackground and Aim In the recent years, a lot of studies show that the balance between oxidation and anti-oxidation in vivo changes in the process of aging, which presents as the enhancement of the oxidization and attenuation of the anti-oxidation, but the abnormal cell product a lot of ROS. If the ROS has the stronger ability of disoxidation than the system of the anti-oxidation, the cells will be at the state of oxidative stress, and this may affect the cells functional status, or even cause the expression of apoptosis related gene, which can activate the procedure of apoptosis. These antioxidant systems include antioxidant molecules such as -tocopherol, ascorbic acid, and glutathione and antioxidant enzymes such as glutathione peroxidase and superoxide dismutase. When the levels of ROS exceed the cellular antioxidant capacity, cells are subjected to oxidative stress, and oxidative damage occurs. The old men have insufficient androgenic hormone and thereafter a series of clinical symptom. Because the old men are influenced by aging and all kinds of diseases, this study was designed to establish the subacute aging male rat model with D-galactose-induced and evaluate the effect of lipid peroxidation on the Leydig cell ultrastructural organization, the level of testosterone in blood, and the expression of bcl-2 and caspase-3 in Leydig cells.Materials and Methods Animals: Twenty SD rats(2-3 months age, weighing 180 to 220g), which were provided by the animal center of the Shantou university medical college, were divided randomly into two groups: the control group(C) and D-galactose group(D). All rats that drank water and took food freely were raised in different cage in the same room, natural illumination, room temperature, relative humidity 50～60％. The normal control group was injected hypodermically with the normal sodium(0.2ml/100g)every day for six week, while Dgalactose group was injected hypodermically with the autoclaving D-galactose(200mg/kg)every day for six week.Fourty-eight hours after the last injection in the sixth week, the rats were anesthetized with sodium pentobarbital by intraperitoneal injection. After that, the scrotum was clipped, the tissue around the testicle was separated, and the testicular artery was legated, and then the left testicle was obtained quickly, weighed and homogenized. Next the level of the SOD, GSH-PX and MDA were detected, then testicular tissue was taken which was fix by 2.5％glutaraldehyde, and then ultrathin section was made, following the ultramicrostructure was observed by transmission electron microscope. The chest was opened and 2 ml blood was taken from the apex of heart. Blood serum which was centrifuged in low temperature was stored in 4℃for the use of testosterone radio-immunity. The left ventricle was clipped, a perfuse-pinhead was inserted into the ascending aorta and was fix with the hemostatic forceps. Right atrium was clipped and peffused with NS 100～150ml when the blood was washed out, then 4％polyoxymethylene(4℃,500ml)was perfused into ascending aorta. The other testicle was obtained and fix with 4％polyoxymethylene over night, and then was imbedded into paraffin and was sliced. Finally, the expression of bcl-2 and caspase-3 in the interstitial tissue of testis was detected.Results: Compared with the C group, endoplasmic reticulum and mitochondrion decreased in the Leydig cell of D group. (1) The activities of SOD: D group(116±18.09)NU/mgprot was statistically lower than C group(156±31.02)NU/mgprot(p＜0.01). (2) The level of MDA in testis of D group(1.77±0.41)nmol/mgprot was significantly higher than that in C group(1.19±0.15) nmol/mgprot(p＜0.05). (3) The activities of GSH-PX: D group(29.84±3.79)U/mgprot was statistically lower than C group(35.29±4.50)U/mgprot(p＜0.05); (4) Serum T of D group(0.69±0.26)ng/ml was remarkably lower than that in C group(2.58±0.73)ng/ml(p＜0.05). (5) The expression of bcl-2 in the Leydig cell of D group(35.1±3.6)％was remarkably lower than C group(49.6±7.4)％(p＜0.05). (6) The expression of caspase-3 in the Leydig cell of D group(11.3±1.8)％was remarkably more than C group(9.1±1.3)％(p＜0.05).Conclusions: Lipid peroxidation highly influenced the ultrastructure, the concentration of serum T and the expression of bcl-2 and caspase-3 in the Leydig cell of aging rats.
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