Muscle fiber conduction velocity and enzyme histochemistry of muscle in a rat model of chronic cerebral hypoperfuson.
A rat model of chronic cerebral hypoperfusion was prepared to clarify the effect of reduced cerebral blood flow on histological and electrophysiological changes in muscle fibers. After the bilateral common carotid arteries of eight-week-old rats were bound with a ligature, the rats were reared for another four weeks or eight weeks. Following measurements of muscle fiber conduction velocity (MFCV) in the soleus muscle, enzyme histochemical assessment of the same muscle was performed using ATPase staining. MFCV and muscle fiber size were compared to those of normal rats. The mean cross-sectional area of muscle fibers decreased in every fiber type except type 2B after the ligation of bilateral common carotid arteries. Since the rats did not exhibit motor paralysis judging by appearances, the decrease in muscle fiber area was considered to be indicative of disuse muscle atrophy. In addition, the mean MFCV value decreased significantly after the ligation of bilateral common carotid arteries, and there was a significant correlation between MFCV and muscle fiber area. Although both muscle fiber atrophy and decreased MFCV improved in eight weeks after the ligation of bilateral common carotid arteries, conversion of muscle fiber types from type 2 to type 1 progressed more than in normal rats.
