[A study on testicular aromatase activity--spermatogenic damage in high testicular E2 models of rat]

In order to study the influence of testicular estrogen concentration on spermatogenesis, we conducted the following experiments.

Eight-week-old male Sprague-Dawley rats were used and two kinds of experiments were prepared. In experiment one (intraperitoneal injection), five groups were set up: control (saline solution), estradiol (E2), human chorionic gonadotropin (hCG), aromatase inhibitor (A.I.) and hCG+A.I. group. In experiment two (intratesticular injection), two groups were set up: control (saline solution) and E2 microcrystal suspension (Emcs) group. The experimental period was 28 days. At sacrifice, we evaluated the concentrations of serum testosterone (T) and E2, testicular T and E2, testicular aromatase activity and the seminiferous tubular diameter.

Exp. 1: In the hCG group, the rate of testicular aromatase activity and testicular E2 level were higher and the diameter of seminiferous tubules was smaller than in the control group. However, these changes were not observed in the hCG+A.I. group. Exp. 2: In the Emcs group, testicular E2 level showed an increase without elevation of serum E2 level, and the diameter of seminiferous tubules was atrophic.

It was suggested that the increase of the rate of testicular aromatase activity and the following elevation of testicular E2 level is possibly one of the causes of male infertility.