Abstract
It has been pointed out that chronic blood flow reduction may cause exhaustion of masseter muscles, which is known as one of the symptoms of temporomandibular disorders. However, details have not yet been clarified. The present study investigated the influence of chronic blood flow reduction on the skeletal muscle fibers using a chronic blood flow reduction model of rat lower limbs. Soleus muscle (type I fiber-rich muscle) and extensor digitorum longus muscle (type II b fiber-rich muscle) were selected for this study, and changes of muscle fibers were examined enzyme-histochemically and biometrically.
In this model, significant reduction of blood flow had been maintained at least 3 months after ligation of the sinistral external iliac artery. The influence of chronic blood flow reduction was significant in the soleus muscle, appearing as a smaller proportion and attenuation of type I fibers. In contrast, no significant changes were observed in the extensor digitorum longus muscle.
The results suggest that chronic blood flow reduction of the masseter muscle, which is known as type I fiber-rich muscle, may induce the small proportion and attenuation of type I fibers resulting in exhaustion of the masseter muscle.
