Dietary natural astaxanthin at an early stage inhibits N-nitrosomethylbenzylamine–induced esophageal cancer oxidative stress and inflammation via downregulation of NFκB and COX2 in F344 rats

Purpose: Esophageal cancer is a common malignant tumor that develops rapidly and has a poor prognosis clinically. Astaxanthin (AST) is a carotenoid pigment with strong antioxidant, anti-inflammation, and antitumor activities. However, little is known about the effects of astaxanthin in esophageal cancer. The present study aimed to investigate the protective effects and related mechanisms of natural astaxanthin against N-nitrosomethylbenzylamine (NMBA)-induced esophageal cancer in rats. Methods: F344 rats were induced subcutaneously with NMBA dissolved in dimethyl sulfoxide (0.35 mg/kg body weight three times per week for 5 weeks). Rats were fed normal diets with or without 25 mg/kg/day AST at different stages. At different time points, levels of oxidative stress factors in serum and esophagus tissue were analyzed. Western blotting was performed to observe the expression of NFκB and COX2 in esophagus tissue. Results: AST clearly reduced the incidence of visible tumors in esophageal cancer during the early-stage intervention group. Furthermore, when compared with the simple exposed group, AST significantly increased levels of GPx and SOD activity, decreased the activity level of malondialdehyde (all P<0.05). Early-stage and whole-stage intervention groups effectively attenuated expression levels of NFκB and COX2 proteins compared with the simple exposed group (all P<0.05). Conclusion: Natural AST significantly suppressed the occurrence of esophageal cancer by increasing antioxidant capacity and anti-inflammation capacity by inhibiting expression levels of NFκB and COX2 proteins.