Original Article

Changes muscle and plasma hepatocyte growth factor levels under casting immobilization

Hideto Okazaki, MD, PhD, Hidehiko Beppu, MT, PhD, Kenmei Mizutani, MT, PhD, Shigeru Sonoda, MD, PhD
Jpn J Compr Rehabil Sci 4: 84-87, 2013

Purpose: Hepatocyte growth factor (HGF) contributes to the proliferation of muscle cells, however, the relationship between the level of HGF in muscle and that in the blood is unknown. In this study, we examined the influence of exercise on HGF levels in muscle and blood using a rat model of hindlimb muscle atrophy.
Methods: Thirty female Sprague-Dawley rats were used. Fifteen of the rats were cast-immobilized for 14 days (CAS); the remaining fifteen rats were allowed normal activity as the control group (CNT). After removal of the cast, rats were divided into three groups (n=5 per group) as follows: a pre-exercise group (PE), a normal activity group (normal activity for seven days) (NA) and a treadmill training group (20 slope, 15 m per min, 20 min per day for seven days; TR). The CNT group was also divided into the same three groups. At the end of the study period, the wet weight of the left soleus muscle per body weight, plasma HGF level and left soleus muscle HGF level were measured and multiple comparisons were performed.
Results: Muscle weight was significantly lower in CAS-PE than in all CNT groups. Muscle HGF level was significantly higher in CAS-TR than in either CAS-PE or CAS-NA. There were no statistically significant differences between any of the other groups.
Conclusion: Muscle HGF is expressed in response to relatively high intensity exercise but the dynamics of HGF are limited to intramuscular distribution.

Key words: atrophy, exercise, HGF

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