Testosterone reaction after testicular biopsies--further investigation in the normogonad and cryptorchid rat model

Impact of testicular sperm extraction and testicular sperm aspiration on gonadal function in an experimental rat model

Purpose

To assess the impact of sperm retrieval on the gonadal function of rats with impaired spermatogenesis by comparing testicular sperm extraction (TESE) to aspiration (TESA). The efficacy of these procedures to sperm obtainment was also compared.

Materials and Methods

A pilot study showed impaired spermatogenesis, but normal testosterone (T) production after a bilateral orchidopexy applied to 26 rats, which were randomly assigned into four groups: TESE (n=7), TESA (n=7), SHAM (n=6) and Control (n=6). The T levels were measured through comparative analysis after the orchidopexy.

Results

There was no statistical difference in the animal's baseline T levels after orchidopexy in comparison to the controls: the TESE and TESA groups, 6.66±4.67ng/mL; the SHAM group (orchidopexy only), 4.99±1.96ng/mL; and the Control, 4.75±1.45ng/mL, p=0.27. Accordingly, no difference was found in the postoperative T levels: TESE, 5.35±4.65ng/mL; TESA, 3.96±0.80ng/mL; SHAM, 3.70±1.27ng/mL; p=0.4. The number of sperm cells found through TESE (41.0±7.0) was significantly larger than that found through TESA (21.3±8.1, p=0.001). Moreover, higher tissue weight was found through TESE (0.09±0.02g versus 0.04±0.04g, p=0.04).

Conclusions

The testicular sperm capture performed in rats through extraction or aspiration, after orchidopexy, did not significantly decrease the T levels. The amount of sperm found through testicular sperm extraction was higher than that through testicular sperm aspiration.

Androgen aromatization in cryptorchid mouse testis

Estrogens play an important role in germ cell development. Therefore, we have studied expression patterns of aromatase that converts testosterone into estrogens in 2 recombinant inbred mouse strains that differ in efficiency of spermatogenesis. In order to show whether germ cells are a target for estrogens, estrogen receptors (ER)alpha and beta were localized as well. Adult male CBA and KE mice were made unilaterally cryptorchid to determine alterations in testicular steroidogenesis and spermatogenesis. Differences between control and cryptorchid testes have been studied with respect to (1) cellular sites of aromatase, the enzyme responsible for estrogen formation, (2) the presence of ERalpha and ERbeta in various types of testicular cells, and (3) steroidogenic activity in the testes. Additionally, unilaterally control testes of cryptorchid mice were compared with bilaterally descended testes. Histological or hormonal differences were not found between control testes of cryptorchid and untreated mice. In cryptorchid testes from both strains, degeneration of germ cells was observed as well as a decrease in size of the seminiferous tubules, whereas the amount of interstitial tissue increased, especially in testes of CBA mice. Using immunohistochemistry, aromatase was localized in Leydig cells and germ cells in both control and cryptorchid testes. Sertoli cells were immunopositive in control testes only. In cryptorchid testes of KE mice, aromatase was strongly expressed in spermatids, that were still present in a few tubules. Other cell types in tubules were negative for aromatase. In both control and cryptorchid testes of both mouse strains, ERalpha were present in Leydig cells only, whereas ERbeta were found in Leydig cells and in germ cells in early stages of maturation. In homogenates of testes of CBA control mice, testosterone levels were 3-fold higher than in those of control KE mice, whereas the difference in estradiol levels between both strains was small. Cryptorchidism resulted in decreased testosterone levels and increased estradiol levels. The results of the present study show functional alterations due to cryptorchidism in both mouse strains. Strong aromatase expression in germ cells in control and cryptorchid testes indicates an additional source of estrogens in the testis besides the interstitial tissue and the relevance of estrogen in spermatogenesis.