[Evaluation of testicular damage by flow cytometry: testicular atrophy caused by ethylene oxide]

The new method using flow cytometry was applied to analyse the testicular toxicity of ethylene oxide, and the usefulness of this method is discussed. When Wistar male rats were exposed to ethylene oxide for six hours a day, three times a week for six weeks, the testicular weights of the exposed group significantly decreased. When the cells of these testes were stained by propidium iodide and analysed by flow cytometry, four peaks which corresponded to maturation phase spermatids (less than C), the other haploid cells (C), diploid cells (2C) and tetraploid cells (4C) were obtained. Calculating the ratio of the percentage of less than C, C and 4C to that of 2C, the ratio of less than C of the exposed group decreased by 72.9%, 2C by 53.5% and 4C by 5.1% when compared with the control group. As these changes were almost consistent with that of histopathological examinations, we are able to conclude that more mature germ cells were affected by ethylene oxide. This method by flow cytometry is thought to be objective, quantitative and convenient to evaluate testicular damage by chemicals.