n-3 polyunsaturated fatty acids improve fatigue by inhibiting NLRP3 inflammasome activity of skeletal muscle in exhaustive mice

Abstract

Objective To explore the effect and mechanism of n-3 polyunsaturated fatty acids (n-3 PUFAs) on skeletal muscle inflammation and fatigue in exhaustive exercise mice. Methods Using fish oil gavage to C57BL/6J mice for exogenous intervention of n-3 PUFAs and Fat-1 mice (endogenous synthesis of n-3 PUFAs), a 7-day exhaustive mice model was established. Forty C57BL/6J mice were divided into 4 groups (10 in each group): the blank resting group (CON group), the blank exercise group (EX group), the fish oil resting group (FO group) and fish oil exercise group (FO+EX group). Twenty Fat-1 mice were divided into 2 groups (10 in each group): the Fat-1 resting group (FA group) and the Fat-1 exercise group (FA+EX group). Serum levels of urinel UREA, glucose (GLU), creatine kinase (CK) and lactate dehydrogenase (LDH) were detected by automatic biochemical analyzer. Serum IL-1β and IL-18 levels were determined by enzyme-linked immunosorbent assay. The mRNA expression levels of IL-1β, IL-18, NLRP3, ASC and Caspase-1 in gastrocnemius muscle tissues were detected by RT-qPCR. The protein expression levels of NLRP3 and ASC in gastrocnemius muscle tissues were detected by Western blotting. Kits were used to detect the levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), muscle glycogen and liver glycogen in gastrocnemius muscle. HE staining was used to observe the morphological and structural changes of gastrocnemius muscle. Results n-3 PUFAs decreased the levels of UREA, CK and LDH in exhaustive exercise mice (P < 0.05), and increased the level of GLU (P < 0.05). n-3 PUFAs decreased serum IL-1β and IL-18 levels in exhaustive exercise mice (P < 0.05). n-3 PUFAs inhibited the mRNA expression levels of NLRP3, ASC, Caspase-1, IL-1β and IL-18 in skeletal muscle of exhaustive exercise mice (P < 0.05), and the protein expression levels of NLRP3 and ASC in skeletal muscle of exhaustive exercise mice (P < 0.05). n-3 PUFAs increased the content of liver and muscle glycogen in exhaustive exercise mice (P < 0.05). n-3 PUFAs increased the activities of SOD and GSH-Px in gastrocnemius muscle of mice during exhaustive exercise (P < 0.05), and decreased the content of MDA (P < 0.05). Conclusion n-3 PUFAs can effectively improve the antioxidant capacity and fatigue of exhaustive exercise mice, and the mechanism may be related to n-3PUFAs inhibiting the overactivation of NLRP3 inflammatome in skeletal muscle of exhaustive exercise mice.

Keywords

• n-3 polyunsaturated fatty acids
• exhaustive exercise
• nlrp3 inflammasome
• oxidative stress
• skeletal muscle inflammation
• fatigue