Nicotinamide Riboside Protected Muscle Cells from Heat-Induced Injury: Preclinical Findings

Synopsis

Prolonged exposure to heat stress can damage skeletal muscle (SKM) by disrupting mitochondrial function, but the mechanisms behind this injury are not fully understood. This study found that heat exposure in both muscle cells (C2C12 myoblasts) and mouse skeletal muscle caused significant changes in mitochondrial ion balance and energy metabolism. Specifically, mitochondrial calcium (Ca²⁺) levels increased, while magnesium (Mg²⁺) and NAD+ levels dropped sharply. These changes led to mitochondrial fragmentation, membrane depolarization, and cell death (apoptosis). Supplementing with nicotinamide riboside (NR)—a vitamin B3–derived NAD+ precursor—restored NAD+ levels, reduced mitochondrial damage, and protected muscle cells from heat-induced injury, though it did not alter Ca²⁺ or Mg²⁺ imbalances. The findings suggest that maintaining mitochondrial NAD+ homeostasis with NR could be a promising strategy to prevent heat-related muscle damage and improve muscle resilience under stress.

Journal

Applied Physiology, Nutrition, and Metabolism