GCMS analysis of sadagura (smokeless tobacco), its enhanced genomic instability causing potential due to arsenic co-exposure, and vitamin-C supplementation as a possible remedial measure: a study involving multiple model test systems.

North-eastern states of India, including Assam, have a high prevalence of head and neck cancer cases. In these regions, Sadagura is a unique form of smokeless tobacco (SLT). There are fewer reports regarding the effects of simultaneous sadagura and arsenic co-exposure. Analysis of chemical compounds present in sadagura aqueous extract was done using gas chromatography-mass spectrometry. Estimation of arsenic contamination in groundwater and bioaccumulation in human tissues was performed by using atomic absorption spectroscopy. Buccal micronucleus cytome (BMCyt) assay and analysis of various peripheral blood parameters were performed among study volunteers. Chronic exposure (90 days) experiments were performed in mice test system in vivo to determine any possible protective potential of vitamin C (Vit-C) supplementation against sadagura and arsenic co-exposure. BMCyt assay results revealed a higher incidence of micronucleated cells (p < 0.001), and cell death biomarker among sadagura consumers residing in arsenic affected areas. Comet assay of mice femur bone marrow cells following chronic exposure of the test substances revealed a reduction in DNA damage due to Vit-C supplementation. Histological examination of the hepatic and renal tissues revealed marked improvement due to Vit-C supplementation in mice against sadagura and arsenic chronic co-exposure. Indiscriminate consumption, presence of various harmful compounds in sadagura along with arsenic co-exposure might be a vital link for the higher incidence of oral cancer in the region. Chronic Vit-C supplementation study results in mice show its effective remedial potential against combined sadagura and arsenic co-mediated genotoxicity and ultrastructural changes in major organs.

Consumption pattern and genotoxic potential of various smokeless tobacco products in Assam, India: A public health concern.

Smokeless tobacco (SLT) consumption is presumed to be one of the major causes of high incidence of oral cancer in India. The present study aimed to document various types of SLT products consumed and their potential impact on the genome instability on the population from Assam state in Northeast India. A cross-sectional study (n = 5000) showed that 60.56 % of the study population consumed at least one of the three forms (sadagura, zarda and khaini) of SLT of which 52.0 % were only sadagura users. Genotoxicity assessment using buccal cytome assay in 240 age and sex matched volunteers revealed that except for zarda, other forms of SLT induced significantly higher incidence micronuclei in the buccal epithelial cells compared to the control individuals. Similar effects were also observed in other cytome parameters related to cell proliferation, cytokinesis defects and cell death. Significantly higher incidence of micronucleus was observed among sadagura and khaini users in lymphocyte cytokinesis-blocked micronucleus assay. The addition of lime in sadagura increased the pH and anion levels which possibly result in higher absorption and may lead to the development of cellular anomalies.

Effect of nutritional status on arsenic and smokeless tobacco induced genotoxicity, sperm abnormality and oxidative stress in mice in vivo.

BACKGROUND: Recently, high concentrations of arsenic have been documented in ground waters of Southern Assam, India. Indiscriminate smokeless tobacco consumption is a common practice in this region. Correlation between nutritional status and arsenic and smokeless tobacco-induced health effects has not been taken up in humans or other test systems. METHODS: Mice were divided into groups based on protein (casein) content in the diet: High protein (40%), optimum protein (20%), and low protein (5%). Simultaneous chronic exposure (90 days) to arsenic and smokeless tobacco (sadagura) orally was given to evaluate the extent of the cytological and genotoxicological damage. Micronucleus assay and Comet assay of the femur bone marrow cells were conducted. Germ cell toxicity was evaluated by recording the sperm head abnormalities and total sperm count. Cell cycle analysis was performed in femur bone marrow cells using flow cytometer. Hepatic, renal, and intestinal tissues were analyzed for various oxidative stress evaluations. Histological examination of liver and kidney was performed. RESULTS: Notably, high protein diet groups had lower arsenic and sadagura induced genotoxicity, germ cell abnormalities and oxidative stress as compared to optimum protein and low protein diet counterparts. CONCLUSION: Our study indicates that sufficient levels of dietary protein appear to reduce the long-term arsenic and smokeless tobacco-induced toxicity in mice test system, as compared to lower or deficient amount of protein in the diet. This observation has implications and invites further studies especially epidemiological studies in the human population exposed to arsenic in South East Asian countries. Environ. Mol. Mutagen. 59:386-400, 2018. © 2018 Wiley Periodicals, Inc.