Cadmium chloride's effects on spermiation and sertoli cell microfilaments in the rat.

Abstract

The hypothesis tested was that the seminiferous epithelium is more sensitive to the toxicity of cadmium than the testicular endothelium. Preliminary studies indicated that testicular endothelium was not significantly affected 24 hours after a single cadmium dose of 1 mg/kg. Therefore, for this study, ten week-old Sprague-Dawley rats were administered a single intraperitoneal injection of cadmium chloride at a dose of 1.0 mg/kg body weight. At 4, 24, 48, and 72 hours after injection, testes of animals were perfusion fixed, embedded in plastic, and sectioned. Tissue sections were stained and examined under the light microscope. The organization of microfilaments in the basal region of Sertoli cells was also examined in formalin fixed seminiferous tubules. Seminiferous tubules were isolated and stages of the cycle were determined using transillumination under a stereomicroscope. The tubules were stained with rhodamine-phalloidin and examined using a confocal microscope. Cadmium treatment resulted in failure of spermiation in stage IX 24 hours after injection. Failure of spermiation was observed with increasing frequency within an affected stage as the time of exposure to cadmium increased. Failure of spermiation occurred in stage XIII 72 hours after cadmium injection. Cadmium also resulted in disruption of the Sertoli cell basal microfilaments in stages VIII through XI 24 hours after cadmium treatment. As the exposure time increased, the lesion within a stage occurred with increasing severity, and later stages were also affected. Cadmium was estimated to act during early stage VIII of the cycle of seminiferous epithelium to produce these effects. This cadmium dose did not alter the stage frequencies of individual stages, nor did it affect microfilaments in peritubular cells of the exposed tubules. It is concluded that cadmium chloride, at a dose below that which affects testicular endothelium, results in failed spermiation and disrupts Sertoli cell basal microfilament bundles in rat seminiferous tubules. The action of cadmium on the seminiferous epithelium appears to be stage-specific and cell-specific. This is the first known reported demonstration that the seminiferous epithelium is more sensitive than the testicular endothelium to a low acute dose of cadmium chloride.