RE-EXAMINATION OF LESIONS IN RAT TESTIS CAUSED BY CADMIUM

The early changes in the microvascular bed of the testis resulting from treatment with cadmium were studied with trypan blue, electron dense tracers and by vascular injections. Leakage of fluids and electrolytes from the testicular blood vessels to the interstitium was demonstrated at the light and electron microscope levels as early as 1-2 h following parenteral injection of cadmium. After 1-2 h, discontinuities in the endothelial lining could be detected by the presence of carbon particles in the walls of the testicular capillaries and venules. By 3 h, the extravasation of carbon had increased, such that particles could be seen labeling large veins. Within the vessels, a local increase in the concentration of erythrocytes was noted and numerous platelets adhering to exposed subendothelial structures were seen plugging the endothelial gaps. At 4 h, a striking decrease in labeling of veins was noted due to the fact that delivery of the tracer towards the venous system is almost entirely obstructed as a result of the blockage and progressive deterioration of the smaller vessels; ischemia of the testis ensued from the obstruction of the microvascular circulation. These results indicate that the degeneration of the seminiferous epithelium and all biochemical and physiological changes known to occur in the testis at later time intervals following cadmium treatment are secondary to ischemia rather than due to a direct effect of the cadmium.