Caflisch C R
Department of Internal Medicine, Physiology and Biophysics, University of Texas Medical Branch, Galveston 77555-0562.
J Toxicol Environ Health. 1994 Jul;42(3):323-30. doi: 10.1080/15287399409531882.
Acute injections of high doses of cadmium (Cd) induce marked testicular necrosis. However, the effects of low-dose oral Cd exposure, on a chronic basis, are not well documented. The present investigation was designed to examine the effects of such exposure on in situ pH, PCO2, and bicarbonate concentration ([HCO3-]) in the rat testis and epididymis, plasma testosterone levels, and testis and epididymis weights. Male Sprague-Dawley rats were exposed to 50 or 100 ppm Cd for 40 d. Oral administration of 50 or 100 ppm Cd was associated with significant alkalinization of luminal fluid in seminiferous tubules (ST) but did not alter in situ pH values in proximal caput (PCP), middle caput (MCP), or proximal cauda epididymidis (PCD). The in situ PCO2 values in ST, PCP, MCP, and PCD of control animals were indistinguishable from each other and from values after Cd exposure, and all values were significantly higher than system arterial blood (SAB) PCO2. Oral Cd exposure at 50 or 100 ppm did not change the values for bicarbonate in SAB, PCP, or MCP but increased markedly the value in ST. Plasma testosterone levels and testis and epididymis weights were not altered after oral cadmium administration. These findings suggest that, at the doses employed in this study, Cd exposure may result in subtle alterations in the blood-testis barrier and subsequent impairment of acid-base pathways. Furthermore, the traditional view of Cd-related testicular insult based on acute injection protocols needs to be reevaluated in terms of environmental relevance.
急性注射高剂量镉（Cd）会导致明显的睾丸坏死。然而，长期低剂量口服镉暴露的影响尚无充分记录。本研究旨在检测这种暴露对大鼠睾丸和附睾原位pH值、PCO2以及碳酸氢盐浓度（[HCO3-]）、血浆睾酮水平以及睾丸和附睾重量的影响。雄性Sprague-Dawley大鼠暴露于50或100 ppm的镉中40天。口服50或100 ppm的镉会导致生精小管（ST）管腔液显著碱化，但不会改变附睾头近端（PCP）、附睾头中段（MCP）或附睾尾近端（PCD）的原位pH值。对照动物的ST、PCP、MCP和PCD中的原位PCO2值彼此之间以及与镉暴露后的数值无显著差异，且所有数值均显著高于系统动脉血（SAB）的PCO2。口服50或100 ppm的镉不会改变SAB、PCP或MCP中碳酸氢盐的值，但会显著增加ST中的值。口服镉后，血浆睾酮水平以及睾丸和附睾重量未发生改变。这些发现表明，在本研究使用的剂量下，镉暴露可能会导致血睾屏障发生细微改变，并随后损害酸碱途径。此外，基于急性注射方案的与镉相关的睾丸损伤的传统观点需要根据环境相关性重新评估。
