Influence of lead and zinc on rat male reproduction at ‘biochemical and histopathological levels’

Abstract

Sequential lead accumulation and biochemical and histopathological changes were observed in rat testis and epididymis after oral administration at varied doses of lead (10, 50 and 200 mg kg(-1) body wt.) for 3 months and also following the concomitant administration of lead with zinc (1 mg kg(-1) body wt. +50 mg Pb kg(-1) body wt.). Accumulation of lead in both testis and epididymis increased with dose. The concomitant administration of zinc reduced the lead levels. Similarly, dose-related changes were seen in the activities of the enzymes alkaline phosphatase and Na(+)-K(+)-ATPase, which decreased with increased dose of lead. A significant improvement in the activities of these enzymes was seen in the groups given both lead and zinc. Histologically, discernible changes were noticed only at higher doses (50 and 200 mg kg(-1) body wt.), which included disorganization and disruption of spermatogenesis with accumulation of immature cells in lumen of tubule. At higher doses of lead, complete arrest of spermatogenesis was seen and a significant decrease in germ cell layer population was evident. Even in epididymis, the histoarchitecture was disrupted only at higher doses of lead both in the caput and corpus regions. The changes included damage of basement membrane, disorganization of epithelium and vacuolization of cells. The tubules were found almost empty, indicating arrest of spermatogenesis. However, with concomitant administration of lead and zinc both testis and epididymis presented a near-normal picture, indicating the protective role of zinc. Hence, the data indicate that the protective effect of zinc on lead toxicity was mediated largely by significant competition between lead and zinc or due to reduction of the available binding sites.

Effects of Zinc Coadministration on Lead Toxicities in Rats

“…These data suggested that Pb increased abnormal sperm and Zn could decrease it. This agrees with the observation by Batra et al 19,22) . That the toxic effects of Pb on male reproductive system could be ameliorated by Zn supplementation.…”

Testiculo-Protective Effect of Stem Bark Extract of Enantia chlorantha on Lead Induced Toxicity in Adult Wistar Rat (Rattus norvergicus)

“…Also the interstitial spaces were abnormally widened and the Leydig cells were not observable, hence destroyed; this revealed the antifertility action of lead oxide [11]. Photomicrograph of the testis of animal in group treated with both extract of Enantia chlorantha and lead (IV) oxide, shows degenerating of the seminiferous epithelium.…”

Environmental Lead Exposure and Male Infertility

“…Many studies on reproductive system of animals have reported lead as a toxic substance for testicular tissue and functions (29), including spermatogenesis and mature sperm formation (30).It was suggested that spermatogenesis regression is caused by increased inhibin B synthesis in highly lead exposed subjects (31). Many studies agree with this finding (32,33,34,35)including a study which was done on mice and found that there is a significant decrease in the number of spermatozoa within the epididymis in mice exposed to lead acetate in drinking water (36), and prevent spermatogenesis in rats (37). On the other hand some researchers have failed to demonstrate such a correlation between lead and sperm count (38,39).…”