Effects of exercise and body temperature on eNOS, SIRT1, SIRT3 and Hsp70 expression in rat plantaris muscles (1164.6)

Abstract

Previously, we have demonstrated a dramatic increase in mitochondrial biogenesis in skeletal muscle of rats exercise trained while maintaining a constant core temperature. In this study, we explored the role of body temperature during exercise on the expression of multiple proteins (eNOS, SIRT1, SIRT3, and Hsp70) believed to play a role in mitochondrial biogenesis. Female, Sprague‐Dawley rats (5 mos of age) were divided into three groups sedentary (S), exercise in 22°C room (ET), and exercise while maintaining core temperature (E). Exercised animals trained for 5 weeks on a motor‐driven treadmill at 30 m/min, 60 min/day, 5 days/wk during final 2 wks. Core temperature was held constant in E by reducing room temp to 6‐8°C. Plantaris cytochrome oxidase activity (μmoles O2/min/g wet wt) was significantly (P<0.05) elevated in both ET (37.00±2.10) and E (47.14±4.11) versus S (24.15±1.37) and significantly greater in E versus ET. Preliminary results reveal no significant differences in SIRT1, SIRT3, or eNOS expression in the soleus muscles of S, E, or ET. Hsp70 was significantly (P<0.05) elevated in the ET group. These data suggest that although mitochondrial biogenesis increases in this model, eNOS, SIRT1 and SIRT3 do not parallel this increase and may not play a role in this process.