Cessation of contact altered toxic effects of diesel on heavy metal metabolism but not on renal dysfunction
Iyanda AA, Aina OO
Although petroleum products are known toxicants, there is dearth of information on how effective the different physiological mechanisms in mammals are, in correcting altered heavy metal metabolism and renal dysfunction commonly associated with diesel exposure. The objective of the study therefore is to explore that possibility. Forty female rats (180 - 210 g) were divided into 4 groups of 10 rats each. 3 mL/kg was administered daily to rats in GROUPS 2, 3, and 4 for 21 days, GROUP 1 constituted the control. Rats in GROUPS 2 and 4 received diesel orally as constituent of feed but diesel was administered by dermal route to GROUP 3. Blood samples were obtained and rats were euthanized on 22nd [GROUPS 1-3] and 50th day [GROUP 4]. Serum levels of heavy metals were determined by Atomic Absorption Spectrometry. Evaluation of renal damage was by estimation of serum levels of creatinine and urea. Histologic examination of kidney was by hematoxylin and eosin. Statistical analysis of the data was by analysis of variance (ANOVA). p≤0.05 was considered significant. Pd, Cd, Al, Ni, and As were significantly higher in GROUPS 2 and 3 compared with Group 1. As, Cd, and Pb were significantly lower in GROUP 4 compared with GROUP 2 or GROUP 3, but they were not significantly different compared with GROUP 1. 10% death rate was observed among GROUP 4 rats. No visible lesion (GROUP 1); but various degree of distortion in renal histo-architecture in GROUPS 2-4 were also observed as well as abnormal urea and creatinine levels. In conclusion, data obtained reveals that altered heavy metal metabolism as well as renal dysfunction occurred from both oral and dermal contact and that its nephrotoxic effects lasted well beyond the immediate period of contact.