Renal Induced Damage Following Mercury Exposure in Adult Wistar Rats

Abstract

This study investigated the histomorphological effect of mercury chloride on the kidney. Heavy metals are hazardous substances that cause serious health risk to ecosystems and organisms due to their high toxicity conferred by nature of their environmental persistence. Mercury is a well-known toxic heavy metal to animals as well as humans. Mercury occurs naturally in the environment in different chemical forms. Elemental mercury is the form used in dental amalgams. Forms more commonly found in nature are inorganic mercury and organic mercury. All mercury forms are considered toxic. It is being widely used in the industrial, medical, agriculture and other fields. Materials and Methods: Thirty six (36) adult wistar rats of both sexes, weighing between 110 g-300 g were randomly divided into four groups A, B, C, and D with nine animals per group. The animals in groups B, C, and D were administered mercury chloride orally at the concentration of 0.2 mg/kg, 0.4mg and 0.5 mg/kg body weights respectively while group (A) served as control and was given distilled water. The administration lasted for a period of 21 days and on the 22nd day all the groups of rats were sacrificed by cervical dislocation, blood was collected through cardiac puncture and the kidneys were carefully removed and weighed immediately with a sensitive balance and then fixed in 10% formol saline. The tissues were processed and sectioned and stained with haematoxylin and eosin stain for histological studies. The results showed that the mean kidney weight in groups B and C increased insignificantly (P>0.05), compared to the control group while group D decreased significantly compared to the control group. In the biochemical analysis there was significant increase (P<0.05).in alanine transaminase,, aspartate transaminase and alkaline phosphatase activities in mercury- treated group B, C and D compared to the control group A. Histological study of the kidney revealed that C and D treated groups showed marked degenerative changes, fibrosis and hemorrhage showing varying degrees of renal injury marked by focal sclerosis of the glomerulus, widening of the Bowman’s space and hyper cellularity and complete collapse of the glomerulus. The study concluded that exposure to mercury chloride induced nephrotoxic effect on the kidney of adult wistar rats.