Testicular Degeneration and Spermatid Retention in Young Male Rats

Abstract

The incidence of spontaneous testicular atrophy and its morphological changes in relation to stage-specific spermatogenesis were investigated in young Crl:CD/BR male rats at 10-12 wk of age used as controls for toxicity screening during 1983-1990. The incidence of testicular degeneration was 2.5% (5/197) in control rats used for oral toxicity studies and 9.4% (31/327) in rats used for inhalation studies. The epididymal tubules of rats with testicular degeneration had exfoliated germ cells and low sperm density. The high incidence of testicular degeneration observed in the control rats used in inhalation studies may be related to the stress associated with immobilization in the restrainer during nose-only exposure conditions. The severity of testicular degeneration in the inhalation studies was mostly minimal. In these minimally affected testes, mature spermatids (step 19) were retained within normal-appearing germinal epithelium at spermatogenic stages IX-XIV. Also, eosinophilic globular bodies (EGBs) were formed with elongated or mature spermatids throughout all spermatogenic stages, but the general architecture of germinal epithelium was normal in appearance. By electron microscopy, EGBs were sequestered necrotic spermatids, and the germ cell degeneration was associated with cytoplasmic vacuolation of Sertoli cells. In moderate testicular degeneration, markedly decreased maturing spermatids (steps 15-19) and a slight depletion of round spermatids were observed in stages I-VIII. In severe testicular degeneration, seminiferous tubules were lined with 1-2 layers of round spermatids and spermatocytes with giant cell formation. The round spermatids served as a marker to identify spermatogenic stages (I-VIII) of the atrophic tubules. Also, in severe testicular degeneration, tubules in spermatogenic stages X-XIV had no elongated spermatids, and spermatocytes were exfoliated with occasional giant cell formation. Many seminiferous tubules were lined with only 1-2 layers of spermatocytes, and specific germ cell markers were not present.

Toxic effects of Carthamus tinctorius L. (Safflower) extract on mouse spermatogenesis

“…Other studies have reached similar conclusions [18,19]. Many studies have been performed by qualitative [20,21] or quantitative [22,23] examination to detect testicular toxicity. In this study, we performed qualitative examination of germ cell morphology by histopathology and quantitative examination using morphometry and Johnsen scoring.…”

Impact of Oxidative Stress and Supplementation with Vitamins E and C on Testes Morphology in Rats

“…These alterations indicate degenerative processes of the testes (17,18). The decrease in the number of seminiferous epithelial layers could be the result of spermatogonium B mitosis inhibition, which denotes elongation of the G1 phase of the cell growth cycle.…”

Toxic effects of dexamethasone on mouse testicular germ cells

“…Disorders of spermatogenesis may be arbitrarily thought of as having quantitative and/or qualitative components. Many studies have been performed by qualitative (Hew et al, 1993;Lee et al, 1993) or quantitative (Creasy et al, 1985;Matsui et al, 1995) examination to detect testicular toxicity. Qualitative evaluation involves the Leydig cells and their subcellular features, blood vessels, cell infiltration, basement membranes, multinucleated giant cells, Sertoli cell morphology, missing germ cells, abnormalities of germ cells and germ cell development and disruption of the Sertoli cell barrier (Russell et al, 1990).…”