Synergistic effects of selenium and silicon mitigate arsenic toxicity in plant (Oryza sativa L.) and human model (keratinocyte HaCaT cells lines) systems

Arsenic (As) is a toxic element for plants, animals and humans. The mitigation of As stress has been achieved via selenium (Se) and silica (Si) supplementations. However, the effects of combined application of Se and Si against As stress are not known. The present study was conducted on a plant (rice; Oryza sativa L.) and human model (keratinocyte HaCaT cell lines) systems to evaluate the effects of Se (0.5 and 1 mg L − 1 ) and Si (10 and 30 mg L − 1 ) against As (4 mg L − 1 ). The rice plants, grown hydroponically for 7 d in various treatments, showed reduction in As accumulation in As + Se/Si/Se + Si treatments in comparison to As treated plants. The reduction in As accumulation in root and shoot was 57% and 64%, respectively in As + Se + Si treatment. The increase in enzymatic antioxidant system (SOD, APX, GPx, GR and GST) along with decrease in oxidative stress markers (MDA, DHA, ASC and H 2 O 2 ) in As + Se + Si treatment as compared to As treatment signified elevated tolerance of rice plants to As stress. The cytotoxicity amelioration by Se + Si supply was also seen in HaCaT cells exposed to As in terms of cell viability and As-induced shrinking and apoptosis. In conclusion, the results demonstrated that an optimum combination of Se and Si can be effectively used to mitigate As toxicity in plants and possibly humans also.