Rathinasamy Baskaran

Protective effect of gallic acid against lindane induced toxicity in experimental rats

Lindane is an organochlorine pesticide that persists in the environment, bioaccumulate through food chain and has a risk of causing adverse effects to human health and the environment. It induces cell damage by producing free radicals and reactive oxygen species. The aim of the present study is to investigate the protective effect of gallic acid (a plant derived polyphenol) against lindane induced hepatic and renal toxicity in rats. Liver damage was assessed by hepatic serum marker enzymes like SGOT, SGPT and ALP and histopathological observation. Renal damage was observed by histopathological examination and serum markers like creatinine and urea. Treatment with lindane increased the levels of lipid peroxidation, serum marker enzyme activity with a concomitant decrease in GSH, CAT, SOD, GPx and GST. Histological alterations were also observed in kidney and liver tissue with lindane treatment. Co-treatment of gallic acid significantly prevented the lindane induced alterations in kidney and liver tissues with a decrease in LPO, serum marker enzyme activity and a significant increase in antioxidant levels. These results suggest that gallic acid has protective effect over lindane induced oxidative damage in rat liver and kidney.

Quercetin attenuates lindane induced oxidative stress in wistar rats

A wide number of pesticides, including highly persistent organochlorine compounds, such as lindane (γ-Hexachlorocyclohexane), have deteriorative effect on fauna and flora by inducing oxidative stress. Lindane induces cell damage by producing free radicals and reactive oxygen species. Quercetin, a dietary flavonoid, is ubiquitous in fruits and vegetables and plays an important role in human health by virtue of its antioxidant function. In this study the flavonoid quercetin was used to investigate its antioxidative effect against lindane induced oxidative stress in rats. The level of lipid peroxidation, reduced glutathione (GSH) were analysed in addition to the antioxidant enzymes such as catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD) and glutathione-s-transferase (GST) activities in the liver and kidney tissue. Levels of hepatic marker enzymes in serum like Aspartate transaminase (AST), Alanine transaminase (ALT), Alkaline phosphatase (ALP) and Lactate dehydrogenase (LDH) and renal markers like serum creatinine and serum urea were estimated. Administration of Lindane induced histopathological alterations and increased levels of serum hepatic and renal markers and malondialdehyde (MDA) with a significant decrease in GSH content and CAT, SOD, GPx and GST activities. Cotreatment of quercetin along with lindane significantly decreased the lindane induced alteration in histology, serum hepatic and renal markers and MDA and also improved the cellular antioxidant status. The results show that Quercetin ameliorates Lindane induced oxidative stress in liver and kidney. The quercetin exhibited chemopreventive effect when administered along with lindane.

Effect of quercetin against lindane induced alterations in the serum and hepatic tissue lipids in wistar rats

OBJECTIVE To assess the effect of quercetin (flavonoid) against lindane induced alterations in lipid profile of wistar rats. METHODS Rats were administered orally with lindane (100 mg/kg body weight) and quercetin (10 mg/kg body weight) for 30 days. After the end of treatment period lipid profile was estimated in serum and tissue. RESULTS Elevated levels of serum cholesterol, triglycerides, low density lipoprotein (LDL), very Low Density Lipoprotein (VLDL) and tissue triglycerides, cholesterol with concomitant decrease in serum HDL and tissue phospholipids were decreased in lindane treated rats were found to be significantly decreased in the quercetin and lindane co-treated rats. CONCLUSIONS Our study suggests that quercetin has hypolipidemic effect and offers protection against lindane induced toxicity in liver by restoring the altered levels of lipids. The quercetin cotreatment along with lindane for 30 days reversed these biochemical alterations in lipids induced by lindane.

Neferine prevents NF-κB translocation and protects muscle cells from oxidative stress and apoptosis induced by hypoxia

Neferine (Nef), a bisbenzylisoquinoline alkaloid from lotus seed embryo has a wide range of pharmacological activities. Possible molecular mechanism for the cytoprotective action of Nef during hypoxic stress has not been explored till now. Hence, this is an attempt to elucidate the molecular mechanism involved in the Nef mediated cytoprotection on hypoxia-induced cell injury. Cytoprotective dose of Nef in muscle cells (Human rhabdomyosarcoma cells) exposed to hypoxia was determined by MTT assay. Nef at 500 nM offered better cytoprotection and was used for all the experiments. ROS, intracellular calcium accumulation and mitochondrial membrane (ΔψM) potential were measured using fluorescent probes. Further, we evaluated the effect Nef on hypoxia induced inflammatory and apoptotic responses by FACS and analyzing the expression patterns of NF-κB, COX-2, HIF-1α, caspase-3, caspase-9, Bcl2, and Bax. The results of this study revealed that pretreatment of the cells with Nef significantly decreased the ΔψM and ROS in the cells subjected to hypoxia. Further, Nef inhibited NF-κB there by inhibiting the expression of its downstream regulator COX-2, while it induced the functional HIF-1α expression. The results also indicate that Nef significantly inhibited the ROS dependent mitochondrial mediated apoptosis induced during hypoxia. The cytoprotection elicited by Nef in a model of hypoxia induced cell death involves both anti-inflammatory and anti-apoptotic response. These results suggest that Nef may be used as prophylactic agent against the hypoxic challenge.

Enhancement of beta-catenin in cardiomyocytes suppresses survival protein expression but promotes apoptosis and fibrosis

BACKGROUND Beta-catenin has been implicated in cell-cell communication in a wide variety of developmental and physiological processes. Defective Wnt signaling could result in various cardiac and vascular abnormalities. Little is known regarding Wnt/frizzled pathway in cardiomyocyte apoptosis. METHODS In this study, the role of b-catenin in apoptosis was investigated in H9c2 cardiomyocytes and primary cardiomyocytes isolated in diabetic Wistar rats. The cardiomyocytes were transfected with porcine cytomegalovirus (pCMV)-b-catenin plasmid in order to overexpress b-catenin. RESULTS The transcription factor displayed a significant nuclear localization in Wistar rats with cardiac hypertension. Transfection of b-catenin plasmid induced apoptosis and reduced expression of survival pathway markers in cardiomyocytes in a dose-dependent manner. Furthermore, expression of fibrosis protein markers was upregulated by the overexpression. CONCLUSIONS Taken together, these results revealed that altered Wnt/b-catenin signaling might provoke heart failure. (Cardiol J 2017; 24, 2: 195-205).

Neferine, a bisbenzylisoquinoline alkaloid, offers protection against cobalt chloride-mediated hypoxia-induced oxidative stress in muscle cells

Background Neferine, a bisbenzylisoquinoline alkaloid, isolated from Nelumbo nucifera has a wide range of biological activities. Cobalt chloride (CoCl2) was known to mimic hypoxic condition. In the present study, we assessed the cytoprotective effect of neferine against CoCl2-induced oxidative stress in muscle cells. Methods Rhabdomyosarcoma cells were exposed to different concentrations of CoCl2, and the IC50 value was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Lactate dehydrogenase and NO assays were performed in order to determine the cytotoxic effect of CoCl2. Reactive oxygen species generation and cellular antioxidant status were determined for evaluating oxidative stress. For analyzing the effect of neferine on CoCl2-induced apoptosis, propidium iodide staining was performed. Results The results of the present study indicate that CoCl2 induces cell death in a dose-dependent manner. Neferine pretreatment at 700 nM concentration offers better cytoprotection in the cells exposed to CoCl2. Lactate dehydrogenase and NO release in the culture medium were restored after neferine pretreatment. CoCl2 triggers time-dependent reactive oxygen species generation in muscle cells. Further, results of propidium iodide staining, mitochondrial membrane potential, and intracellular calcium accumulation confirm that neferine offers protection against CoCl2-induced hypoxic injury. Depleted activities of antioxidants such as superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase due to CoCl2 exposure were also reinstated in the group that received neferine pretreatment. Conclusion Our study suggests that neferine from N. nucifera offers protection to muscle cells by counteracting the oxidative stress induced by CoCl2.

Neferine ameliorates cardiomyoblast apoptosis induced by doxorubicin: possible role in modulating NADPH oxidase/ROS-mediated NFκB redox signaling cascade

Doxorubicin (DOX) mediated cardiomyopathy is a major challenge in cancer chemotherapy. Redox-cycling of doxorubicin by flavoenzymes makes the heart more vulnerable to oxidative stress leading to cardiac dysfunction. The present study evaluates the role of neferine, a bisbenzylisoquinoline alkaloid, in curbing the molecular consequences of DOX-exposure in H9c2 cardiomyoblasts. Neferine pre-treatment increased cell viability upon DOX-exposure. DOX activates NADPH oxidase subunits, (p22phox, p47phox, gp91phox) as the primary event followed by peak in [Ca2+]i accumulation by 2 h, ROS by 3 h and activated ERK1/2 and p38 MAPKinases, time dependently along with the activation and translocation of NFκB and up-regulated COX2 and TNF-α expressions. Neferine pre-treatment modulated NADPH oxidase/ROS system, inhibited MAPKinases and NFκB activation, reduced sub G1 cell population and concomitantly increased cyclin D1 expression reducing DOX-mediated apoptosis. The study demonstrates for the first time, the molecular sequential events behind DOX toxicity and the mechanism of protection offered by neferine with specific relevance to NADPH oxidase system, MAPKinases, inflammation and apoptosis in H9c2 cells. Our data suggests the use of neferine as a new approach in pharmacological interventions against cardiovascular disorders as secondary complications.

Oxaliplatin resistance in colorectal cancer cells is mediated via activation of ABCG2 to alleviate ER stress induced apoptosis

Oxaliplatin (OXA), is a third generation platinum drug used as first‐line chemotherapy in colorectal cancer (CRC). Cancer cells acquires resistance to anti‐cancer drug and develops resistance. ATP‐binding cassette (ABC) drug transporter ABCG2, one of multidrug resistance (MDR) protein which can effectively discharge a wide spectrum of chemotherapeutic agents out of cancer cells and subsequently reduce the intracellular concentration of these drugs. Role of ABCG2 and plausible molecular signaling pathways involved in Oxaliplatin‐Resistant (OXA‐R) colon cancer cells was evaluated in the present study. OXA resistant LoVo cells was developed by exposing the colon cells to OXA in a dose‐dependent manner. Development of multi drug resistance in OXA‐R cells was confirmed by exposing the resistance cells to oxaliplatin, 5‐FU, and doxorubicin. OXA treatment resulted in G2 phase arrest in parental LoVo cells, which was overcome by OXA‐R LoVo cells. mRNA and protein expression of ABCG2 and phosphorylation of NF‐κB was significantly higher in OXA‐R than parental cells. Levels of ER stress markers were downregulated in OXA‐R than parental cells. OXA‐R LoVo cells exposed to NF‐κB inhibitor QNZ effectively reduced the ABCG2 and p‐NF‐κB expression and increased ER stress marker expression. On other hand, invasion and migratory effect of OXA‐R cells were found to be decreased, when compared to parental cells. Metastasis marker proteins also downregulated in OXA‐R cells. ABCG2 inhibitor verapamil, downregulate ABCG2, induce ER stress markers and induces apoptosis. In vivo studies in nude mice also confirms the same.

Tinospora cordifolia extract attenuates cadmium-induced biochemical and histological alterations in the heart of male Wistar rats

Persistence of cadmium (Cd) in the environment causes serious ecological problems. Tinospora cordifolia is a medicinal herb used in Ayurveda for treating various metabolic disorders and toxic conditions. The present study investigates the protective effect of T. cordifolia stem methanolic extract (TCME) on a heavy metal, Cd-induced cardiotoxicity in male Wistar rats. Male albino Wistar rats were divided into four groups (n=6). The animals after treatment for 28days with Cd and TCME were analysed for biochemical and histological changes in the serum and heart tissues. Cd induced lipid peroxidation and protein carbonylation was significantly reduced by TCME. TCME also reduced the histological alterations induced by Cd treatment in the heart tissues with diminished loss of myocardial fibers. Administration of TCME effectively prevented the altered levels of serum marker enzymes (creatine kinase and lactate dehydrogenase), antioxidants, such as superoxide dismutase, catalase, glutathione, glutathione peroxidase and glutathione-S-transferase, and glycoproteins contents such as hexose, hexoseamine, fucose, and sialic acid by Cd intoxication. TCME also offered protection against the change in levels of Na+K+ATPase, Mg2+ATPase and Ca2+ATPase activities against Cd toxicity. The study suggests TCME as a potent cardioprotective agent against Cd induced toxicity.

Modulatory effect of Tinospora cordifolia extract on Cd-induced oxidative stress in Wistar rats

Background Cadmium (Cd), a nonessential heavy metal, is a major environmental and public health concern. Oxidative stress plays an important role in Cd-induced kidney dysfunction. Tinospora cordifolia, a medicinal plant rich in phytochemicals, possesses antioxidant activity. The objective of the present study was to assess the protective effect of Tinospora cordifolia-stem methanolic extract (TCE) on Cd-induced nephrotoxicity in Wistar rats. Methods Male Wistar rats were administered ∼5 mg/kg body weight Cd orally and 100 mg/kg body weight TCE for 28 days. At the end of Cd and TCE treatment, biochemical assays were performed in serum and tissue homogenate. Results Cd-induced oxidative stress in the kidney resulted in increased levels of lipid peroxidation and protein carbonyl content with a significant decrease in cellular antioxidants, such as reduced GSH, SOD, CAT, GPX, and GST. Cd-induced nephrotoxicity was further confirmed by marked changes in the histology of the kidney and increased levels of kidney markers. Additionally, Cd-treated rats showed alterations in membrane-bound ATPase activity and decreased levels of tissue glycoproteins. Cotreatment with TCE considerably reduced the biochemical alterations in serum and renal tissue induced by Cd, and also restored ATPase activity and glycoproteins to near normal levels. Conclusion Our results suggested that TCE with its antioxidant effect offered cytoprotection against Cd-induced toxicity in kidneys by restoring the altered cellular antioxidants and renal markers. TCE treatment for 28 days reversed ATPase activity and tissue glycoprotein levels. These results revealed the protective effect of TCE on Cd-induced toxicity in kidneys and oxidative stress.