Studies on the recovery of testicular damage following chronic gamma irradiation

Abstract

Eight groups of male rate, 12 in each group, were subjected to various total radiation doses ranging from 300 to 1000 roentgens in 100r intervals. The total dose was fractionated at the rate of five roentgens per 23-hour day. As each group received its maximum radiation dose, the group was removed from the radiation chamber. Four of the 12 rats were sacrificed the same day, another four were sacrificed on the 42nd day following their removal from the chamber and the remaining four male rats were sacrificed on the 84th day following their removal from the chamber. Four control rats were sacrificed on the 90th day of the experiment, an additional four on the 230th day of the investigation. Day one is determined from the day the experimental animals were placed in the radiation chamber. The body and testes weights of all sacrificed animals were recorded. Criteria used to evaluate the testicular damage caused by the irradiation and the subsequent testicular recovery were the following: 1) testes weight, 2) testes weight/ testes weight of controls, 3)tubular diameter, 4) number of leptotene spermatocytes per tubule, 5) number of pachytene spermatocytes and 6) the number of depleted tubules per testicular cross section. An analysis of the histological weight data resulted in the following conclusions: 1) Age, within the limits of this research, is not a factor which alters spermatogenesis of the male rat; 2) testes weight is an important criterion in determining the degree of damage and the subsequent testicular recovery; 3) forty-two days is sufficient time interval for complete spermatogenic recovery from radiation (300-1000r) induced damage; 4) the greater portion of total spermatogenic damage occurs during the absorption of the first 300 roentgens; and 5) eighty-four days is not a sufficient length of time to permit complete testicular recovery.