Protective Effects Of Exercise On Endotoxin-Induced Acute Lung Injuries In Obese Rats

Background: The aim of this study was to investigate the effects of exercise on endotoxin-induced acute lung injuries in obese rats. Methods: Male Sprague-Dawley rats were randomly divided into three groups: normal diet (N), high fat diet (HF), and high fat diet + exercise (HF+E). N group rats were fed with a normal diet. HF group and HF+E group rats were fed with a high fat diet for 10 weeks, while HF+E group rats were trained with daily exercise for 6-10 weeks. ALI model was established by intratracheal administration of LPS after the last physical test. Pulmonary function and histopathology were performed to evaluate the severity of ALI. Serum levels of lipid metabolism parameters and inflammatory factors were measured by automatic analyzer and ELISA, respectively. TREM1 and TREM2 expression was detected by real-time PCR and Western blot. NF-kappa B activation was also measured by Western blot. Results: LPS instillation resulted in severe acute lung injuries in obese rats, compared with the N group, as impaired pulmonary resistance and elastane function increased lung wet-to-dry weight ratios and histopathological injuries and elevated inflammatory factors. Exercise resulted in the decrease of lung injuries in obese rats. TREM1 expression was significantly increased in the HF group, whereas TREM2 was decreased. Exercise reversed TREMs expression. NF-kappa B was activated in the HF group and inhibited by exercise. Conclusion: Present findings suggest that obesity aggravated the severity of ALI, which could be protected by exercise. Exercise might be a potential preventive approach for ALI through regulating TREMs expression, NF-kappa B activation, and inflammatory factor release.