| In order to study the effects of gossypol on the testicular spermatogenic cell apoptosis in male mice. Forty eight health male mice(4-5 weeks old) weighed 20.21±1.56 g as the test subjects. Mice were housed at constant temperature(25℃) for 7 days to adapt the environment and then mice were divided randomly into four groups: control group, low-dose group(30 mg?kg-1?d-1), middle-dose group(60 mg?kg-1?d-1) and high-dose group(120 mg?kg-1?d-1), 12 mice in each group. The mice in 3 dosage groups were orally administrated with gossypol which diluted by sodium carboxymethyl cellulose once daily for 20 days, while the control group were given equal quantity of sodium carboxymethyl cellulose. In the 21 st day, all of mice were killed and their testis had been obtained. Testis were saved and processed in order to be used for each test. The histopathological changes in testes were observed by standard light microscopes; transmission electron microscopy was used to study the effect of the gossypol on the ultrastructures of testicular spermatogenic cell; the apoptosis of testis cell was detected by TUNEL staining; immunohistochemistry was used to detect the expression of Bcl-2 and Bax protein in testicular spermatogenic cell; the expression of Bcl-2 mRNA and Bax m RNA in testicular spermatogenic cell were detected by RT-PCR. The research result showed as follows: the tissue structure of testis was observed by HE staining showed that the control group was not changed significantly, the minor abnormalities of tissue structure of testis in low-dose group and middle-dose group were observed, in high-dose group, the structure was destroyed, the structure of the organization was loose, the wall of seminiferous tubule thinning, spermatogenic cells had irregular arrangement, sperm count had decreased, a considerable number of spermatogenic cells fallen off lumen, even without immature sperm.Ultrastructural integrity and the clear vision of organelle structure in the control group; ultrastructure was abnormity in low-dose group, such as cytoplasm and nuclear matrix was not evenly distributed, degenerated organelles in the cytoplasm, irregular edge of nucleus; ultrastructure of high-dose group and middle-dose group was destroyed seriously. the autophagosomes could been observed, acrosome- membrane structure was broken in high-dose group and middle-dose group. The distribution of TUNEL-positive cells were significantly different in control group, compared with control group, the apoptotic index of spermatogenic cell in low-dose group was affected by the gossypol but the effect was not remarkably(P>0.05), the apoptotic indexes of spermatogenic cells in high-dose group(P<0.01) and middle-dose group(0.01<P<0.05) were definitely higher than the control group. Compared with control group and low-dose group, the expression of Bax protein in middle-dose group(0.01<P<0.05) and high-dose group(P<0.01) was showed a significant rise; the expression of Bcl-2 protein in high-dose group and middle-dose group was definitely lower than the control group(P<0.01, 0.01<P<0.05). With the increasing of gossypol dosage, the expression quantity of testicular Bcl-2 m RNA first increased and then decreased; compared with the control group, the low-dose group showed a significant increase(0.01<P<0.05), middle-dose group and high-dose group showed a significant decrease of the Bcl-2 m RNA expression(0.01<P<0.05, P<0.01); compared with the low-dose group, the middle-dose group and high-dose group showed a significant decrease of the expression of Bcl-2 m RNA(0.01<P<0.05, P<0.01); compared with the middle-dose group, the Bcl-2 mRNA expression in the high-dose group showed a significant decrease of(0.01<P<0.05). Compared with the control group, the middle-dose group and high-dose group showed significant increase of the Bax mRNA expression(0.01<P<0.05, P<0.01); the high-dose group showed a significant increase of the expression of Bax mRNA(0.01<P<0.05), when it compared with the low-dose group.Above all, gossypol can destruct the testicle structure and induce cellular apoptosis, the mechanism associated with decreasing in expression of Bcl-2 and increasing in expression of Bax. |
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