IMPROVEMENT EFFECT OF LONG-TERM VITAMIN D SUPPLEMENTATION ON SKELETAL MUSCLE FATIGUE IN OVERTRAINING RATS

Fu-Lin Lu¹,Ling-Heng Kong^{2, *} 

¹The Athletic Department of Xi’an Medical University, Xi’an - ²Department of Basic Medicine, Xi'an Medical College, Xi’an, China

Introduction: To investigate the improvement effect of long-term vitamin D supplementation on skeletal muscle fatigue in rats and related mechanism.

Materials and methods: The skeletal muscle fatigue rats were prepared and divided into four groups according to whether vitamin D was supplemented and whether there was skeletal muscle fatigue, namely control group (Con), exercise group (Exe), control + vitamin D supplementation group (Con+VD) and Exercise + vitamin D supplementation group (Exe + VD). The levels of vitamin D, serum IL-1β, TNF-α and IL-6 in rats were detected by Elisa; the exercise ability of rats was observed by open field test and rotating rod fatigue test. The levels of IL-1β, TNF-α and IL-6 in rat gastrocnemius muscle were detected by RT-PCR. The expressions of NLRP3 and Caspase-1 in the gastrocnemius muscle of rats were detected by Western Blot. 

Results: The vitamin D level decreased significantly in the Exe group, but increased significantly in Con+VD and Exe+VD; the exercise ability decreased significantly in the Exe group, but increased significantly in Exe+VD; the inflammation level of the rats was significantly higher in the Exe group than in the other three groups. Skeletal muscle IL-1β was significantly negatively correlated with 25(OH)D3, 1,25(OH)2D3, walking distance, rod time, and rod rotation speed. The expression of NLRP3 and Caspase-1 was significantly increased in the Exe group, but decreased significantly after vitamin D supplementation. 

Conclusion: Vitamin D supplementation can alleviate the muscle fatigue state and improve the exercise ability of overtraining rats by regulating the inflammation level in the body.