High-fat diet affects measures of skeletal muscle contractile performance in a temperature-specific manner but does not influence regional thermal sensitivity

The present study examined whether high-fat diet (HFD) consumption for 20 weeks had a temperature-specific effect on the contractile performance and regional thermal sensitivity of isolated mouse soleus and diaphragm muscle. Four-week-old female CD-1 micewere randomly selected to consume either a standard laboratory diet or a standard laboratory diet in conjunction with a HFD for 20 weeks. Peripheral soleus and core diaphragm were isolated from each animal and maximal isometric force and work loop power were assessed at 20, 28, 35 and 40 degrees C. Increasing temperature to 35 degrees C resulted in greater isometric stress, lower activation and relaxation time, and higher work loop power in both muscles. A further increase in temperature to 40 degrees C did not affect isometric force but increased work loop power output of the soleus. Conversely, isometric force of the diaphragm was reduced and work loop power maintained when temperature was increased to 40 degrees C. HFD consumption resulted in greater isometric force and absolute work loop power of the soleus and reduced isometric stress of the diaphragm, effects that were less apparent at lower temperatures. When the relationship between temperature and each measure of contractile function was examined by linear regression, there was no difference in slope between the control or HFD groups for either the soleus or diaphragm. These results indicate that whilst contractile function initially increases with temperature, the temperature to elicit maximal performance is muscle and contractile mode specific. Furthermore, HFD effects on contractile function are temperature specific, but HFD does not influence the relationship between temperature and performance.

Automated summary

This study examined the effects of high-fat diet on muscle contractile performance and thermal sensitivity in mice. The results showed that increasing temperature initially improved contractile function, but the optimal temperature for maximal performance differed depending on the muscle and contractile mode. Moreover, high-fat diet had specific effects on contractile function, but did not alter the relationship between temperature and performance.