Effect on blood, liver, and kidney variables of age and of dosing rats with lead acetate orally or via the drinking water

The redox status in rats treated with flaxseed oil and lead-induced hepatotoxicity

Lead is a persistent environmental pollutant, and its toxicity continues to be a major health problem due to its interference with natural environment. In the present study, we have evaluated the effect of flaxseed oil on lead acetate-mediated hepatic oxidative stress and toxicity in rats. Lead acetate enhanced lipid peroxidation and nitric oxide production in both serum and liver with concomitant reduction in glutathione, catalase, superoxide dismutase, glutathione reductase, glutathione-S-transferase, and glutathione peroxidase activities, these findings were associated with DNA fragmentation. In addition, lead acetate caused liver injury as indicated by histopathological changed of the liver with an elevation in total bilirubin, serum alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transpeptidase, and alkaline phosphatase. Treatment of rats with flaxseed oil resulted in marked improvement in most of the studied parameters as well as histopathological features. On the basis of the above results it can hypothesized that flaxseed oil is a natural product can be protect against lead acetate-mediated hepatic cytotoxicity.

The effect of zinc supplementation on the effects of lead on the rat testis

With increasing concerns about environmental pollution, the interaction of micronutrients with toxic metals is of great interest. The present study was designed to investigate testicular effects of lead following concomitant administration of zinc. Lead was administered orally as lead acetate (50 mg/kg b.w.) daily for 3 months to male Portan rats with or without zinc (1 mg/kg b.w. as zinc sulphate). The control group was given the same volume of distilled water. Endpoints included lead concentration in various body organs as well as in the reproductive system, including testicular subfractions; the testicular enzymes superoxide dismutase (SOD) and catalase; the marker enzyme delta-aminolevulinic acid dehydratase (delta-ALAD); and testicular histoarchitecture. The concentrations of lead in bone, kidney, prostate, testis, liver, epididymis, spleen, seminal vesicles, and blood were significantly higher in lead-treated rats. Lead deposition was reduced in animals that received supplemental zinc. There was a 30% reduction in lead deposition in the testis when zinc was coadministered. At the subcellular level, there was differential accumulation of lead; the nucleus preferentially took up the metal after lead treatment alone, while zinc coadministration shifted lead accumulation to the mitochondria. A significant decrease in delta-ALAD and in SOD activity was seen in the testis with lead treatment. Coadministration of zinc prevented these decreases, at least partially. Zinc coadministration did not prevent the inhibition of catalase observed with lead treatment. Histologically, the alterations in the testis with lead treatment alone were more pronounced compared to animals in which zinc was supplemented. Improvement in the inhibition of delta-ALAD and in the ubiquitous cellular enzyme SOD suggests less testicular tissue damage due to detoxification of free radicals. In conclusion, zinc supplementation ameliorates lead-induced testicular damage both at the cellular and subcellular level. The protective effect may be due to differential distribution of lead, either because of competition between lead and zinc or displacement of lead by zinc.

Biokinetics of lead in various organs of rats using radiotracer technique

Uptake, distribution, and elimination of lead in various organs of rats have been studied using a radiotracer technique. The elimination data for various organs, except whole blood, is fitted to a double-exponential function using a computer program. The biological half-lives along with the percent elimination of lead by two different decay modes in testis, epididymis, prostate, and seminal vesicles are being reported together with that in liver, kidney, blood, and whole body. It is evident from this study that the elimination of lead is limited for all the organs and permits lead accumulation in the bone, where it is stored and becomes almost unavailable for elimination. Lead levels in blood, testis, and femur of lead acetate-fed rats measured using atomic absorption spectroscopy have been correlated to the uptake of 210Pb in various organs.

Renal toxicity after oral administration of lead acetate during pre- and post-implantation periods: effects on trace metal composition, metallo-enzymes and glutathione

The present study was undertaken to compare the effects of 10-50 mg/kg b.wt. of Pb acetate after chronic treatment through oral gavage on: (a) the distribution of trace elements such as Fe, Cu, Zn, and Mn, (b) enzyme activity of delta-amino levulinic acid dehydratase (delta-ALAD) and alkaline phosphatase, and (c) glutathione (GSH) in kidney and (d) delta-ALAD in blood of pregnant and non-pregnant mice. Treatment with Pb acetate was given on every alternate day for 4 weeks prior to mating and for 3-4 weeks until pregnancy became apparent and confirmed by laporatomy. Lead administration reduced the rate of reproduction as assessed by number of living viable embryos. During normal pregnancy renal Cu, Fe and GSH tended to decline although non-significantly and continued to do so after lead administration. Mn was considerably and significantly elevated, whereas activity of delta-ALAD (non-activated) was quite low in pregnant mice. Following administration of Pb acetate, kidneys of pregnant and non-pregnant dams accumulated Pb in a dose-dependent manner, but as compared to non-pregnant mice, Pb increase in pregnant dams was significantly lower. Pb toxicity was associated with the loss of delta-ALAD in blood and kidney, but unlike the non-activated form of delta-ALAD, the dithiothreitol-activated form of delta-ALAD declined in a significant amount. The residual activity showed a high degree of negative correlation with endogenous Pb as well as with Zn/Pb ratio. Pb toxicity did not modify renal Fe, Cu, and Zn in the pregnant state, but reduced renal Fe during pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of diet on the response in rats to lead acetate given orally or in the drinking water

Liver lead levels were higher for rats that were orally dosed with 100 mg lead acetate/kg body wt and fed a semipurified diet than those fed a pelleted diet. The activities of delta-aminolevulinic acid dehydratase in blood were decreased in the group given 10 micrograms lead acetate/mL in their drinking water and fed the semipurified diet, but not in the blood from the group treated with lead and fed the pelleted diet. The levels of glutathione in the liver decreased in response to lead acetate in the drinking water of rats fed the semipurified diet, but not in the livers from the group fed the pelleted diet and treated with lead. The levels of lead in the kidneys were higher in the group given lead acetate in their drinking water and fed the semipurified diet than in the lead treated group fed the pelleted diet. Rats dosed orally with lead or given lead in the drinking water and fed the semipurified diet were more sensitive to lead treatment than those fed the pelleted diet.