Investigation of the Ameliorating Effects of Dietary Supplementations of Plant Materials on Sodium Arsenite-Induced Biochemical and Molecular Perturbation in Mice

Abstract

Major cause of arsenic poisoning is the drinking of water contaminated by arsenic. Recently high levels of arsenic have been found in the several food items in the arsenic-endemic areas suggesting that exposure to arsenic is unavoidable. In this situation, phytobioremediation may be a plausible way to reduce arsenic toxicity. This study was designed to investigate the protective effects of plant materials having antioxidant and free radical scavenging activity against sodium arsenite (Sa)-induced toxic effects through mice model. Mice were divided into eight equal groups: control, Raphanus sativus leaves (RSL), Momordica charantia fruits (MCF), Brassica nigra leaves (BNL), sodium arsenite (Sa), RSL plus Sa, MCF plus Sa and BNL plus Sa. Sa (10 mg/kg body weight/day) was given orally, and plant materials (50 mg/Kg body weight/day) were given as food supplement. Results showed that serum lactate dehydrogenase (LDH) activity was significantly (p < 0.05) higher in Sa-treated mice than that in the control group. RSL and MCF supplementation decreased Sa-induced serum LDH activity significantly (p < 0.05). Serum butyryl cholinesterase activity (BChE) in Sa-treated mice was significantly (p < 0.05) lower than the control group, and food supplementation of RSL but not MCF and BNL could significantly (p < 0.05) prevent the reduction of Sa-mediated serum BChE activity. Sa administration increased the serum biomarkers used for liver function test that include alkaline phosphatase (ALP), Aspartate aminotransferase (AST), and Alanine aminotransferase (ALT) activities. RSL was found to reduce the Sa-induced elevation of these enzyme activities in serum significantly (p < 0.05). MCF was found to significantly (p < 0.05) inhibit only Sa-induced elevation of ALP activity, but not AST and ALT activities. BNL did not show any significant protective effect on Sa-induced elevation of these three enzymes. High density lipoproteins cholesterol (HDL-C), a serum biomarker of cardiovascular risk was found to be significantly lower in Sa-treated mice than that in the control group. RSL but not other two plant materials (MCF and BNL) showed significant (p < 0.05) protection against Sa- mediated perturbation of serum HDL-C levels. Finally Sa treatment increased the serum urea levels significantly (p < 0.05). RSL could reduce the Sa-induced elevation of serum urea level significantly (p < 0.05). However, MCF and BNL could not show any significant protective effects on Sa-induced elevation of serum urea levels. All these results explicitly stated that Sa treatment caused the perturbation of blood indices in mice associated with hepatic, cardiovascular and renal dysfunctions, and RSL showed protection against Sa-induced perturbation of the blood indices more effectively than the two other plant materials (MCF and BNL). Since RSL showed the highest protection against Sa-induced perturbation of blood indices among the three plant materials tested, efficacies of RSL were tested through molecular approaches. Molecular part of this study targeted on the gene expression of heat shock proteins (HSPs). HSPs are stress sensitive molecular chaperon that can be expressed by heat, oxidative stress, heavy metals etc. In regular reverse transcription polymerase chain reaction (RT-PCR), it was observed that Sa treatment could increase the expression of several forms of hepatic and renal HSP genes such as HSP90α, HSP90β and HSP70. Intriguingly, RSL supplementation inhibited the Sa-induced hepatic expression of HSP90α, HSP90β and HSP70 genes. In kidney, RSL reduced the expression of Sa-induced HSP90β, while it showed almost no protective effect on Sa-induced HSP90α and HSP70 expression. For the further confirmation of the effects of RSL on Sa-induced expression of HSP genes, real time PCR was performed. Based on the real time PCR data, Sa treatment significantly (p < 0.05) enhanced the expression of hepatic HSP90α, HSP90β and HSP70. RSL showed significant protective effect on Sa-induced hepatic expression of HSP genes. In kidney, Sa treatment significantly (p < 0.05) increased the expression of HSP90α and HSP90β genes. Although Sa treatment up-regulated the expression of HSP70 gene compared to the control, this up-regulation was not statistically significant. RSL showed to have a general trend in the inhibition of Sa-induced renal expression of all three HSP genes; however, RSL-mediated inhibition was significant (p < 0.05) only in the Sa-induced up-regulation of HSP90α gene, but not in HSP90β and HSP70 genes. All these results indicated that RSL could be useful to reduce or prevent arsenic toxicity in human in future.