Histone acetyltransferase TIP60 mediates spermatozoa damage induced by microwave irradiation in rats

The aim of the current study was to investigate the effects of microwave irradiation on rat spermatozoa, examining the roles of histone acetyltransferase TIP60 in this process. Laboratory rats (n=54) were randomly divided into the control group, radiation group, and radiation + Traditional Chinese Medicine (TCM) group. Rats in the radiation and TCM groups received radiation for 15 minutes at 100 mW/cm(2). The TCM group was treated with intragastric administration once a day for 7 days after radiation. On days 1, 2, 7, and 14 after radiation, rat semen/testis was collected. Sperm motility was measured. Hematoxylin and eosin staining was performed on testis sections. Terminal deoxynucleotidyl transferase dUTP nick-end labelling was used to detect apoptosis of spermatogenic cells. The ultrastructure of the sperm was observed by electron microscopy. TIP60, p53, and tubulin expression was detected by Western blot analysis. Testis sections of the rats demonstrated dyszoospermia in the radiation group, compared with controls, but lighter than the TCM group. Ultrastructure imaging of sperm in the radiation group demonstrated oligospermatism, dolichocephalia, trochocephalia, congenital acrosome absence, and mitochondrial disorder. There was a regular cell layer, high sperm density, and sharp axoneme in the TCM group. Following radiation, the percentage of apoptotic androgones was remarkably increased. At day 1 and day 2, the percentage was significantly higher in the radiation group than in the TCM group (P<0.05). At days 7 and 14, it was decreased, compared with earlier time points, but remained significantly higher than the TCM group (18.51 +/- 3.58) and control group (P<0.05). At days 1, 2, and 14, sperm counts in the TCM group (24.67 +/- 3.55, 21.40 +/- 2.21 and 25.60 +/- 4.68) were significantly different from the radiation group (34.50 +/- 3.43, 8.83 +/- 0.19 and 13.50 +/- 2.35; P<0.05). At day 7, counts were significantly lower in the radiation group than the control group (P<0.05). Sperm density levels and percentages of grade A + B sperm were also measured. They were ameliorated by TCM treatment following radiation. TIP60 expression was detected in semen by Western blotting on day 1, day 2, and day 14. At days 1, 2, and 14, p53 expression was higher in the TCM group than the radiation group. The mechanism of sperm injury by radiation may be that radiation damages DNA. This damage increases TIP60 histone acetyltransferase activity and promotes p53 acetylation. As a downstream target of TIP60, p53 can regulate repair of damaged DNA. In conclusion, TCM treatment increases p53 expression and reduces sperm radiation damage.