Amelioration by Vitamin A upon Arsenic Induced Metabolic and Neurotoxic Effects

Abstract

Arsenic effect was studied at two dosage levels (0.5 mg and 1 mg/kg) for 45 days in two regions of brain, viz., cerebral hemisphere (CH) and cerebellum (C) in adult mice. This study included the antioxidant profile namely superoxide dismutase (SOD), catalase, lipid peroxidation, reduced glutathione, ascorbic acid and total sulphydryl groups. Adenosine triphosphatase (ATPase), succinic dehydrogenase (SDH), phosphorylase together with glycogen and protein levels were also estimated as metabolic indices in the brain regions of mice. A notable decrease was detected in the activities of the enzymes and in the levels of other metabolites together with a significant increase in the lipid peroxidation, glycogen and inorganic arsenic levels after arsenic administration. Supplementation of vitamin A to the arsenic treated mice brought about no significant variation in these antioxidant and metabolic indices in comparison to that of control, revealing amelioration by vitamin A on arsenic exerted metabolic and neurotoxic effects in mice.Key words ---arsenic, vitamin A, antioxidant system, metabolic and neurotoxic effect in part by inducing rapid burst of reactive oxygen species (ROS) in mammalian cells, resulting in oxidative stress 12,13) and carcinogenesis in man. 14) Studies document that arsenic generates ROS such as hydrogen peroxide, superoxide (O 2•-), hydroxyl (OH • ) and peroxyl (ROO • ) radicals. 13) These free radicals and the other reactive species are constantly produced in the brain in vivo.15) Experiments on human fetal brain explants on exposure to arsenic in culture have showed disturbances in lipid peroxidation, generation of ROS and apoptosis. 16) Adenosine triphosphatase (ATPase) and succinic dehydrogenase (SDH) (enzymes of the inner mitochondrial membrane) are concerned with respiration, and energy generation; hence, are essential for cell survival. Respiratory chain is the major source of ROS, hence mitochondrial oxidative damage is thought to be a proximal cause of metabolic effects. 17,18) Metabolism in fish brain was also affected by arsenic poisoning 19) in addition to other pathological effects in general metabolism of animal tissues. 20)

Fertility enhancing activity and toxicity profile of aqueous extract ofChasmanthera dependensroots in male rats

“…In the present study, sodium arsenite might have generated free radicals (as revealed by the elevated levels of MDA) that overwhelmed the antioxidant defence system (as evident from the reduced levels of nonenzymatic [reduced glutathione and ascorbic acid] and enzymic antioxidants [superoxide dismutase and catalase]). The significant decrease in the activities of superoxide dismutase and catalase of rats treated with sodium arsenite in the present study is similar to previous reports by Wu, Chiou, Wang, Hsueh, Wang, Chen, & Lee (), Bashir, Sharma, Irshad, Gupta, and Dogra () and Gopalkrishnan and Rao (). In contrast, the reduction in the level of MDA by AECDR is an indication that the AECDR effectively scavenged the free radicals generated from the sodium arsenite assault and consequently reduced lipid peroxidation.…”

Hepatoprotective effect of Amaranthus hypochondriacus seed extract on sodium arsenite-induced toxicity in male Wistar rats

“…The reduced activities of SOD, CAT and GPx observed in this study points out hepatic damage in the rats administered with SA, and is probably due to exhaustion of these enzymes to scavenge excessively-generated superoxide and hydrogen peroxides, respectively; in tumour cells (Manoharan et al, 2006). The reduced activity of SOD, CAT and GPx of rats treated with SA is in agreement with previous results (Bashir et al, 2006;Gopalkrishnan and Rao, 2006;Wu et al, 2001). Reduced activities of SOD, CAT and GPx in erythrocytes have been reported in cancer (Balasenthil et al, 2000).…”

Immunotoxic and Genotoxic Effects of Arsenic and Ameliorative Potential of Quercetin and Probiotics in Wistar Rat

“…The present biochemical investigations in the NaAsO 2 treated group indicated significant elevation in plasma MDA and MPO values and reduction in CAT, SOD, GSH, and DNA parameters with DNA damage as typical signs of oxidative stress and lipid peroxidation induced by As [33] [34]. There is growing evidence indicating that arsenic toxicity is a hallmark of the excess generation of intracellular ROS, such as superoxide anion (O 2 − ), hydroxyl radical (OH), and hydrogen peroxide (H 2 O 2 ), which are responsible for oxidative damage and lipid peroxidation that play imperative roles in the biochemical alterations of cells [35].…”