Changes of mitochondria calcium and cytochrome C in epididymis associated with apoptosis in varicocele rats / 中国组织工程研究

ABSTRACT

BACKGROUND: Varicocele (VC) can induce the infertility in males, so the investigation on its mechanism is important for the treatment of male infertility. OBJECTIVE: To analyze the effects of VC induced by surgical operation on the contents of mitochondria calcium, cytochrome C and cell apoptosis as well as the changes of microstructure and ultrastructure in epididymis. DESIGN: Randomized control experiment. MATERIALS The experiment was conducted in Jiamusi University between June 2003 and May 2004. Forty male adolescent Wistar rats with the average body mass of (220±20) g were selected, which were provided by the Animal Laboratory of Jiamusi University. Rats were randomly divided into sham-operation group and deligation group with 20 rats in each group at one week after feeding at room temperature. METHODS: Rats in the sham-operation group were made into sham-op eration models by exposing the left renal vein. Rats in the deligation group were deligated of partial left renal veins so as to establish VC models. Bilateral epididymides were removed at ten weeks after operation. The levels of mitochondria calcium in head and body of epididymis as well as the contents of cytochrome C and cytoplasm cytochrome C were detected. The cell apoptosis was detected by in situ terminal deoxynucleotityl transferase mediated dTUP nick end labeling (TUNEL) technique. The specimens of corpus epididymis were routinely made for observation under optimal microscope and electron microscope. The changes of microstructure and ultrastructure of epididymis were studied.MAIN OUTCOME MEASURES: The contents of mitochondria calcium, cytochrome C and cytoplasm cytochrome C. Cell apoptosis. Changes of cellular morphous in epididymis. RESULTS: A total of 40 rats were involved in the analysis of results.① The contents of mitochondria calcium in bilateral epididymis were obviously decreased in the deligation group than the sham-operation group [(4.72±1.45), (5.90±1.97), (10.13±2.34) mg/g, (P ＜ 0.01)].②The content of mitochondria cytochrome C in right epididymis obviously increased more in the deligation group than the sham-operation group [(0.36±0.20), (0.19±0.14), (0.15±0.07) μmol/L (P ＜ 0.05)]. ③The contents of cytoplasm cytochrome C in bilateral epididymis greatly increased more in the deligation group than the sham-operation group [(8.17±1.49), (7.48 ± 1.60), (5.93±1.60) mol/L, (P ＜ 0.05)].④The apoptotic rate of bilateral cells in the deligation group was significantly increased than the sham-op eration group [( 13.3±1.9)%, ( 12.6±1.5)%, (6.2±0.3)%,(P ＜ 0.01 )]. However, there were no significant differences in mitochondria calcium, cytochrome C, cytoplasm cytochrome C and apoptotic rate between the left and right mitochondria of the deligation group (P ＞ 0.05).⑤Main changes under light microscope cuctus epididymis shrinked, the blebbing appeared in epithelial cells, and the light cells as well as halo cells in epithelia were significantly increased. ⑥Main representation under electron microscope the cytolysosome inside the chief cells were increased and enlarged with increased residual bodies, and the endoplasmic reticulum expanded, the mitochondria cristae was dim, the Golgi complex was vacuolated. Besides, nuclear chromatin were dense and in lump at different size, which located mainly in the nuclear membrane. The microvilli of columnar epithelial cells were sparse and local defects could be seen. CONCLUSION: The cytochrome C is released to kytoplasm via mitochondrial outer membrane, which activates the caspase 3 and leads to the apoptosis, and accordingly causes excessive apoptosis of epididymal tissues and as well as the changes of microstructure and ultrastructure. All these changes may be one of the important reasons of infertility resulting from VC.