[Effectiveness of blood-testis and blood-epididymis barriers for lead]

Over the period of the last 30 years there was a marked decrease in the number of spermatozoa produced by the gonads of men. It is felt that this observation is due to the influence of environmental pollution, wherein the lead plays quite an important role. In sperms of men, who are professionally exposed to lead compounds, oligo-, asteno-, and teratospermia is disclosed. Studies were performed on sexually mature male rats after 9-month-long exposure to lead acetate (II) as well as a group of animals after 3-month-long interval in the exposure. The changes provoked by the lead were evaluated by employing a number of study techniques, namely: morphological examination of testes with taking into account the stages of seminiferous epithelial cycle, and epididymis, giving due consideration to zones; electron microscopic examination of seminiferous cells and interstitial tissue, as well as the cells in the wall of epididymis and spermatozoa; X-ray microanalysis determining the presence and type of elements on ultrathin section; spectrophotometrical determination of Pb content in blood, testes and epididymides; determination of testosterone concentration (T) in blood serum. It has been revealed that the blood-testis barrier protects seminiferous epithelium against the toxic action of the lead. No deposits of Pb were observed either in germinal cells or Sertoli cells. The endocrine testicular cells outside the barrier had also unchanged ultrastructure, and contained no Pb. That finding was expressed by normal T level in blood serum. The only cells in the area of the testis, in whose cytoplasm there was Pb confirmed by X-ray microanalysis, were macrophages in the interstitial tissue of the testis. Apart from that, it has been disclosed that the blood-epididymis barrier does not provide a barrier against this element. Pb deposits were seen in smooth myocytes, epithelial cells and in the lumen of epididymal duct. That correlated with a marked decrease in the number of epididymal spermatozoa and numerous damages involving their ultrastructure. It has been shown that the lead, when passing to the duct lumen of epididymis through cells and structures constructing the wall of that organ, is being excreted from the male genital system with the sperm.