Betaine alleviates methomyl-triggered oxidative stress-mediated cardiopulmonary inflammation in rats through iNOS/Cox2 and Nrf2/HO1/Keap1 signaling pathway.

Methomyl (MET), a universally used insecticide, has many adverse effects on various organs in both humans and animals including the liver, kidneys, and heart. Betaine (BET), a natural antioxidant, has a protective role against many toxicants-induced cardiovascular disorders. The present study was designed to elucidate the molecular mechanistic way underlying the mitigating effect of BET against MET-induced cardiopulmonary injury and inflammation in rats. Four groups of rats were used and orally administered the consequent materials daily for 28 days: normal saline, BET (250 mg/kg bwt), MET (2 mg/kg bwt), MET + BET. Blood and tissue (heart & lungs) samples were collected to assess the oxidative stress markers, lipid profile, biochemical markers, microscopic appearance, and inflammatory gene regulations. The results proved that MET induced oxidant/antioxidant imbalance, elevation of serum creatine kinase (CK) and lactate dehydrogenase (LDH) levels, and deterioration in lipid profile. The histopathological inspection showed severe myocardial necrosis and interstitial pneumonia along with bronchitis and alveolar damage. There was a marked increase in the intensity of cyclooxygenase-2 (Cox-2) and inducible nitric oxide synthase (iNOS) immunostaining with marked upregulation of the transcriptase levels of keap-1gene and downregulation of nuclear factor erythroid 2-related factor-2 (Nrf-2) and heme oxygenase-1 (HO-1) genes in both heart and lung tissues of MET group. Otherwise, the coadministration of BET with MET markedly alleviated the abovementioned toxicological parameters. We can conclude that BET was able to reduce the MET-induced oxidative stress-mediated cardiovascular injury and pulmonary inflammation by modulating Keap-1/Nrf-2 signaling pathway and inactivating Cox-2 and iNOS expression which therefore reduced further cellular damage and inflammatory response.