Lipid Profile and Malondialdehyde Concentrations in Cadmium-Induced Rats: A Study with Relation to Doses

Cadmium (Cd); a non-essential trace element; is one of the most toxic heavy metals in the environment for plants and animals [1]. Environmental contamination by Cd results from its industrial use and its presence in agricultural fertilizers. This is a subject of serious concern since the metal is known to enter the food chain and can undergo bioaccumulation; endangering human health [2]. In human; non-occupational exposure to Cd predominantly results from smoking; air pollution and consumption of Cd-contaminated sea foods and water [3]. Once absorbed; Cd stimulates the formation of metallothionein (a family of low molecular weight metal binding proteins unique in their high cysteine content available in liver; kidney; intestine and pancreas) and reactive oxygen species. Metallothionein is thought to function in the storage of the essential metals zinc and copper; and to serve as an antioxidant; preventing damage to cellular constituents; but which also retains Cd in the cell. As Cd bound to metallothionein is of small size therefore it is released into the circulation filtered by kidney and reabsorbed by cells of proximal tubules. Cd thus accumulates in renal tubular cells; until the synthetic capacity for metallothionein is exceeded. When the concentration of Cd in the kidney reaches a critical concentration; renal dysfunction is likely to occur; thus causing oxidative damage to tissues and cells by altering lipid peroxidation and loss of membrane functions [4-9]. Cd causes damage to several organs such as liver, kidney, lung and testes following acute intoxication, and nephrotoxicity, immunotoxicity, hepatic dysfunction, osteotoxicity and tumors on prolonging exposures [9-11]. It also affects various structures and metabolic processes; such as nucleic acids, carbohydrate energy metabolism, protein synthesis, and enzyme systems [12]. Several studies have demonstrated that Cd stimulates free radical production in tissues where malondialdehyde is used as an indicator of oxidative damage; resulting in oxidative deterioration of lipids player thereby initiating various pathological conditions in humans and animals [13-15]. The molecular mechanism responsible for the toxic effects of Cd is not well-understood. Several tissues were selected for investigation based on the fact that Cd has been reported to accumulate in all tissues; although the level of accumulation differs; leading to various diseases Volume 1 Issue 5 2015