Effects Of Aerobic Exercise On Energy Metabolism In Vitamin D Deficient Mice

PURPOSE: To explore how vitamin D deficiency affects energy metabolism in mice, and whether aerobic exercise can reverse the harmful effects of vitamin D deficiency on energy metabolism. METHODS: 36 mice were randomly divided into 4 groups: control group (C, n = 9), vitamin D deficient group (VDD, n = 9), control exercise group (CE, n = 9) and vitamin D deficient exercise group (VDDE, n = 9). The C and CE were fed diets containing 1000 IU vitamin D3/kg (VD3/kg), while the VDD and VDDE were fed diets containing 0 IU VD3/kg. After 12 weeks, the VDD model was validated by detecting serum 25(OH)D levels in each group. After successful modeling, CE and VDDE began to perform aerobic exercise training for 12 weeks, and the other two groups were allowed to freely move in their cage. At the end of the intervention period, the energy metabolism of the mice in each group was measured using the mouse metabolic cage, including 24-hour oxygen (O2) uptake, carbon dioxide (CO2) output, respiratory quotient (RQ), and daily energy expenditure (DEE). The difference of energy metabolism in each group was analyzed by one-way ANOVA and data were represented as unstandardized coefficients with 95% confidence intervals. RESULTS: Serum 25(OH)D was significantly decreased in VDD compared with group C after diet modeling (18.5 ± 2.8 vs 109.9 ± 11.8 nmol/L, P = 0.000). VDD model was successfully established. Body weight (36.5 ± 4.6 vs 29.8 ± 2.2 g, P = 0.000) and body fat percentage (BF%) (21.6 ± 5.0 vs 13.8 ± 4.7%, P = 0.000) in VDD was significantly higher than C. Compared with VDD, the VDDE had significantly lower body weight (-4.31 g [-7.18, -1.44], P = 0.003) and lower BF (-15.05 [-18.34, -11.75], P = 0.000) after aerobic exercise. VDD compared with C, 24-hour O2 uptake (68.7 ± 4.6 vs 78.3 ± 2.9 L/kg, P = 0.000), CO2 output (54.7 ± 3.3 vs 70.5 ± 1.0 L/kg, P = 0.000), RQ (0.77 ± 0.04 vs 0.89 ± 0.02, P = 0.000) and DEE (343.2 ± 9.9 vs 390.0 ± 6.2 kal/kg, P = 0.000) were significantly lower. After aerobic exercise, the O2 (12.26 L/kg [9.04, 15.47], P = 0.000), CO2 (17.31 L/kg [14.95, 19.67], P = 0.000), RQ (0.07 [0.05, 0.10], P = 0.000), and DEE (65.24 kal/kg [56.18, 74.31], P = 0.000) of VDDE were significantly increased. CONCLUSIONS: Vitamin D deficiency reduces 24-hour O2 uptake, CO2 output, RQ and DEE in mice. Aerobic exercise can reverse the decline in energy metabolism caused by vitamin D deficiency. This research was funded by the National Key Research and Development Program of China (No. 2020YFC2007005) and Shanghai Planning project of Philosophy and Social (No. 2020ETY003).