Effect of chronic lead exposure on kidney function in male and female rats: determination of a lead exposure biomarker.

Several cytotoxic chemical pollutants inducing peroxidative damages are liable to induce kidney failure. Among these pollutants we find heavy metals such as: lead, nickel, cadmium, vanadium and mercury. Lead is one of the most dangerous metals because it is widely spread in the environment, and because it may be a source of several nervous diseases. The aim of this study is to provide evidence concerning the effect of this metal on the renal function and to try to determine a storage corner in the organism which serves as an indicator of a lead intoxication. Lead acetate was administered by oral route in the drinking water to adult rats aged three months at the rate of 0.3% (P1) and 0.6% (P2). Reference rats received distilled water to drink under the same conditions. The treatment continued for 15, 30, 45, 60 and 90 days. The creatinemia, uremia, glycemia and creatinuria are determined by colorimetric techniques. Lead concentration in blood as well as the lead content of the tail are determined by atomic absorption after nitroperchloric mineralization at the liquid stage. The results showed an increase of creatinemia on the 30th day of the experiment for both sexes in (P1 and P2). The same happened for ureamia. The increase of these two parameters would indicate a renal deficiency which is confirmed by a decrease of creatinuria and urinary pH observed mainly on and after the 45th day of the experiment. An increase of the renal relative weight was noticed in P1 and P2 on the 30th day of the treatment. The determination of the concentration of lead in the blood shows that this factor increases among treated subjects in a constant way, independently of the dose and the duration of the treatment. Nevertheless, the rate increase of lead in the tail seems to be dose-dependent. In conclusion, lead administered by oral route causes a renal deficiency to the rat without distinction between males and females. In addition, the tail seems to be a reliable exposure biomarker that demonstrates lead intoxication. The tail seems to be a dosimeter of lead bio-accumulation. It constitutes an endogenous source of lead impregnation. The concentration of lead in the blood is only an indicator of recent exposure.

[Effects of automobile lead on the general growth and sexual activity of the rat]. / Effets du plomb d'origine automobile sur la croissance générale et l'activité sexuelle du rat.

To identify the active element of automotive exhaust gas responsible for masculine infertility, previously proved by our laboratory, we undertook these experiments. Four hundred young male and female rats were exposed during two months (30 min/d) to three types of automotive exhaust gases. The first type emanated from an engine running on gasoline with lead, the second from an unleaded gasoline engine, the third from a diesel engine. These three engines had the same power (5 horsepower vehicles < 3.5 tons). For the first type of emissions, some lead deposits were found in the lungs by histologic techniques. This gas also induced in male rats the atrophy of the testicle, seminal vesicle and epididym, certain pathological changes in spermatogenesis shown by the histologic study, and a decrease of the serum's testosterone level. In female rats, the relative weights of the ovary and uterus, as well as the percentage of the arrival of oestrus, were not affected by the gaseous treatment. Both the second and third types of gases seemed less active on the masculine sex as far as these parameters are concerned. Our study suggests that, for light vehicles, leaded gasoline pollutes more than unleaded gasoline or diesel fuels, and that the lead present only in the first type would be the active element responsible for the masculine infertility and body weight gain reduction in rats.