Apoptosis and expression of P53 mRNA and protein in mouse spermatogenic cells induced by low dose ionizing radiation / 中国病理生理杂志

ABSTRACT

AIM: The effect of low dose radiation (LDR) with different doses of X-rays on apoptosis and its related gene P53 expression were studied in spermatogenic cells of male Kunming mouse testis. METHODS: The different kinds of spermatogenic cells were separated using density gradient centrifugation and their apoptosis was measured by flow cytometry. At meantime, P53 protein and P53 mRNA was measured with immunohistochemical SABC and in situ hybridization, respectively. RESULTS: The apoptosis in all kinds of spermatogenic cells induced by LDR had a remarkable regularity. When the doses were 0 025 and 0 05 Gy, spermatogone apoptosis was domaint. With the increase in irradiation dose (0 075-0 2 Gy), spermatocytes also showed an apoptotic change, but the apoptotic percentage of spermatogonia was significantly higher than that of spermatocytes. Moreover, the apoptosis of spermatids and spermatozoa scarely occurred after LDR. P53 protein expressed in spermatogonia and spermatocytes in varying degrees, and the former was significantly higher than that of the latter after LDR. With the increase in irradiation dose, P53 protein expression showed a upregulated tendency, but that of spermatids and spermatozoa scarcely occurred. P53 mRNA primarily expressed in spermatids and spermatocytes when the dose was 0 025 Gy. With the increase in irradiation doses (0 05-0 2 Gy), that of spermatogonia also showed an enhancement. P53 mRNA expression in spermatogonia and spermatocytes showed a remarkable dose-effect relationship. CONCLUSION: The apoptosis of spermatogenic cells was selectively induced by LDR of X-rays, which had remarkable the dose-effect and time-effect relationships. The mechanism of the selective apoptosis in spermatogenic cells by LDR is closely related to the upregulation of P53 .