Neuroprotective Role of Nelumbo Nucifera Gaertn on Noise Stress Induced Alterations in Rat Brain

Abstract

BACKGROUND: newlineStress is an important factor which can influence all aspects of a human newlinelife and stressors have changed over years but human physiology remains the newlinesame. Noise is a stressor produces oxidative stress due to increased formation newlineof oxidants, resulting in changes in cell membrane lipid functions, damage of newlineproteins and significant decrease in intracellular antioxidant defense newlinemechanisms in affecting different parts of the brain, leading to degeneration newlineof neurons. This is to show that natural antioxidant mechanism is inefficient newlineand therefore nutritional consumption of antioxidant compounds is important. newlineThe aim of the study is focused to evaluate whether the pretreatment of the newlineethanolic extract of Nelumbo nucifera (NnE) and quercetin (QRCT) prevents newlinenoise induced alterations in plasma corticosterone (CORT) levels in behavior, newlineanxiety state and memory impairement, free radical scavenging newlineenzymes/antioxidants, Heat shock protein 70 (Hsp70) and c-fos gene newlineexpression in the various regions of brain namely medial prefrontal cortex newline(mPFC), hippocampus (HIPPO), hypothalamus (HYPO). newlineMETHOD: newlineStress was induced by noise stress apparatus and various parameters, newlinespatial learning and working memory changes were studied using Eight Arm newlinevii newlineRadial Maze (EARM) apparatus, exploratory and locomotor activity was newlineassessed using Open Field Behavior apparatus (OFB) were assessed. We newlinemeasured the activity of antioxidant enzymes Super Oxide Dismutase newline(SOD), Catalase (CAT), Glutathione Peroxidase (GPx), and the levels of newlineReduced Glutathione (GSH), Vitamin C, protein thiols and Lipid newlinePeroxidation (LPO) were determined to know the oxidative stress status in newlinediscrete regions of the rat brain like medial prefrontal cortex (mPFC), newlinehippocampus (HIPPO) and hypothalamus (HYPO). Histopathologically, newlinerepair of cells in brain cells, liver and kidney was studied. Molecular study newlinewas done by RT-PCR analysis to assess levels of Hsp70 and c-fos. newlineRESULTS: newlineIn this study it is shown that after noise stress exposure there was newlineincreased errors in working, reference memory and time period to move into newlineall baited arms; however, the drug with stress exposed rats showed a decrease newlinein all the above parameters. A statistical significant (plt 0.001) decrease in newlineimmobilization time, number of faecal pellets with concomitant increase in newlineambulation in peripheral, central squares, rearing and grooming was observed newlinein NnE and QRCT control groups when compared to 1,15 and 30 days noise newlinestress exposed groups. In stress group animals a significant increase in LPO, newlineSOD , CAT, GPx, and a decrease in GSH, Vitamin C and protein thiols but newlineviii newlinethese changes was normalized in NnE and QRCT pretreated and stress newlineexposed rats. Hsp70 and cfos protein expression was increased in all stressed newlinegroups, but that was off set in NnE and QRCT pretreated groups and stress newlineexposed rats. newlineCONCLUSION: Noise stress of both acute and chronic nature have newlineproduced alterations in the rats brain lobes with regard to the antioxidant newlineenzymes, non-enzymatic antioxidants, expression of proteins by specific newlinestress genes such as Hsp70, c-fos. The present study revealed evidences about newlinethe ameliorative and compensatory effects of the phytochemical compounds newlineof NnE extract and QRCT. From these finding the therapeutic value of NnE newlineand QRCT over the brain function impairment due to stress is elucidated newlinewhich has far reaching implications in the therapeutic applications at human newlinelevel where dementia and cognitive impairment follow as a sequel to many newlinediseases including cancer newline newline