The Effects of Single Dose Irradiation (500 rads) on Rat Testis

Lew, Jae Huck; Woo, Young Nam

Abstract

Recently, the LHRH analog is used as an endocrine control for the metastatic prostatic cancer. However, it is known to produce an initial increase in plasma testosterone levels for approximately 2 weeks. And this increase may cause to stimulate tumor growth, bone pains and the symptoms of bladder outlet obstruction. But there are still no effective methods reported to prevent this initial flare so far. The author studied the possibilities of local irradiation to the testes to prevent the initial flare phenomenon of LHRH analog treatment. 14 out of total 44 white rats were selected as a control group and the other 30 as a study group. The author gave a single dose of 500 rads to the testes of each rat of study group and sacrificed 5 rats every week as one week interval up to 6 weeks. Then the changes of testicular weight and histopathological readings of both groups were recorded and analyzed. The results of experimental data can be summarized as follows : 1. The testicular weights of study group decreased significantly as compared with those of corresponding age-matched control group. 2. The number of Leydig cells of study group increased than of the age-matched control group. However, most of those increased Leydig cells were observed as degenerated and necrotized. As a result, the real number of mature Leydig cells which could secrete testosterone rather decreased. 3. The Leydig cell index of study group was 109% of the control group at the first week. After the first week, however, the index decreased progressively until sixth week. At sixth week, the index of study group was observed only 66%. From these results, the author suggest that the local testicular irradiation prior to the LHRH analog treatment for the metastatic prostatic cancer can be a possible method to prevent the initial flare phenomenon.