The Comparative Research On The Effects Of Tail Suspension And Hibernation On The Skeletal Muscle In Daurian Ground Squirrel (Citellus Dauricus)

Objective:1) To study the changes of the morphological structure and the type of myofibrilla in soleus in different seasons. 2) To study the changes of the morphological structure and the type of myofibrilla in soleus in different seasons after tail-suspend 14 days. 3) To study the changes of the morphological structure and the type of myofibrilla in soleus during the different peirod of hibernation. 4) To study the changes of the content of myoglobin in different peirod of hibernation.Methods:1) Establish the disuse model of skeletal muscle was achieved by tail-suspension. 2) Fiber types of solues muscle(SOL) in ground squirrel were identified by immunohistochemistry technology with antibody fast-twitch mysion heavy chain(MHC). 3) The cross-sectional area (CSA) of soleus muscle fiber was measured by image analysis software. 4) The myoglobin content of skeletal muscle was measured by the spectrophotometer.Result:1) The comparison of configuration and muscle fiber types of SOL in normal groundsquirrel in fifferent seasons.The SOL muscle wet weight in summer had significant differences between summer and other seasons. But the ratios of the muscle wet weight to body weight had no differences between different seasons (P>0.05); The CSA of the typeⅠmuscle fiber of soleus of ground squirrel was 2219.66μm~2 ,the CSA of the typeⅡmuscle fiber of soleus was 2408.52μm~2. Compared with summer, the CSA of the typeⅠfiber in autumn and winter decreased 7.7%(P>0.05) and 30.01%(P<0.05), respectively, but the spring increased about 3.02%(P>0.05). The CSA of the typeⅡfiber in autumn and winter decreased 24.29%(P<0.05) and 28.45%(P<0.05) , respectively, but the spring increased about 4.98% (P>0.05). The percentage of muscle fiberⅠandⅡhad no changes in different seasons, but in winter has a little upgread tendency.2) The effection of tail-suspend on configration and muscle fiber type of soleus in ground squirrel in fifferent seasons.After 14 days suspension, the body weight of the Ground Squirrel decreased about 2.87%(P>0.05), 9.54%(P<0.05), 7.67%(P<0.05) compared with the control group in sunmmer, winter and spring. The ratios of the muscle wet weight to the body weight had significant difference compared with the control group. The average CSA of the soleus muscle fibers decreased about 50.42%(P<0.01), 36.91%(P<0.01), 24.04%(P<0.01) in summer, winter and spring group compared with the control group. Compared with the control group(summer, winter, spring), the percentage of the muscle fiber had no changes, the muscle type had not transformed.3) The effection of hibernation on configuration and muscle fiber type in SOL in Ground Squirrel.Compared with the CON Ground Squirrel, the body weight of the H-1mon, H-2mon and AH(2d) decreased 16.32%, 21.34%, 29.73%, respectively. The ratios of the muscle wet weight to body weight showed descent tendency during hibernation, compared with the H-2mon, the ratios of the CON and AH(2d) had significant difference (P<0.05). The sebum cutaneum thickness of the H-1mon, H-2mon and AH(2d) decreased about 11.79%(P>0.05), 16.04%(P>0.05), 32.55%(P<0.05) , respectively , compared with the CON. The index of corpulence of the H-1mon, H-2mon and AH(2d) decreased about 7.12%(.P>0.05), 12.82%(P<0.05), 24.67%(P<0.05) respectively , compared with the CON. The CSA of the muscle fiberⅠandⅡin H-2mon and AH(2d) of the Ground Squirrel had significant difference from the CON and H-1mon(P<0.05).The percentage of typesⅠandⅡfibers in soleus did not show significant variation in ground squirrl during hibernation (P>0.05) but only the H-2mon had a little upgrade tendrncy.4) The myoglobin content of skeletal muscle(SOL, EDL) of the Ground Squirrel during different period of the hibernation. Compared with the CON group, the content of myoglobin in H-1mon and H-2mon group had a significant difference(P＜0.05), and had a extremely significant difference with AH(2d) and AH(14d) group(P<0.01). The AH(14d) group compared with the hibernation group also had a extremely significant difference(P<0.01). The EDL myoglobin content had no changes in any group(P>0.05).