Peculiarities of development of mouse male germ cells after intratesticular injection of dipin

Abstract

It has been shown that a single intratesticular injection of the chemical mutagen dipin (experiment) or saline (control) into mice resulted in significant but reversible morphohistological damage of the spermatogenic epithelium. However, unlike the controls, in mutagenized testes these damages were more pronounced. Thus, the process of restoring a normal pattern of spermatogenesis was slower. In addition, on day 35 of fixation, mature gametes were almost completely absent in the cauda epididymis and a large number of sperm cells with abnormal head shape (58.5 versus 1.7% in the controls) appeared in the testes. Using spermatogonial and meiotic micronucleus assay, we found that dipin did not induce a rise in the number of gross chromosomal mutations in the spermatogonial stem cells (SSCs): on days 35, 56, and 100 postinjection, the incidence of aberrant spermatogonia and round spermatids was not significantly different from the saline control. The degree of gametic chromatin decondensation was evaluated after treatment of the cauda epididymal sperm with sodium dodecyl sulfate (SDS) and dithiothreitol (DTT). Judging by the results of the in vitro sperm chromatin decondensation on days 7, 14, 35, 56, and 100 after the injection of dipin or saline, the number of decondensed nuclei decreased sharply in the studied samples as compared with the sperm from intact animals where sperm cells with fully decondensed chromatin prevailed.