The Relation Research Between Hibernation Bout And The Mechanism Of Anti-disuse Atrophy In Ground Squirrel (Spermophilus Dauricus)

Objective:To observe the rules of hibernation bout of the ground squirrel (Spermophilus Dauricus); to study the muscle wet weight, the ratios of the muscle wet weight to body weight, the activity of enzyme in skeletal muscle and the expression level of myosin heavy chain (MHC) of ground squirrel in the hibernation bout, and of rat in the simulated hibernation bout; to research the relation between hibernation bout and the mechanism of anti-disuse atrophy in ground squirrel. Methods:1) The changes of the hibernation bout and interbout were monitored by the traditional sawdust method; the body temperature was measured by the semiconductor point thermometer.2) The CS and LDH activity of SOL and EDL were determined by UV spectrophotometer.3) MHC expression level of SOL and EDL were determined by the SDS-PAGE. Results:1) During hibernation, the body size of ground squirrel has a positive correlation with the hibernation torpor's time, and has a negative correlation to the number of hibernation bouts. The body temperature of ground squirrel has rised as sigmoid curve.2) The muscle wet weight (BW) and the ratios of muscle wet weight to body weight (MWW/BW) of SOL and EDL of ground squirrel which underwent different numbers of hibernation bout have not show difference compared with pre-hibernation and after hibernation; the MHC type of SOL transformed from theâ…¡toâ… , While the MHC type of EDL remain unchanged.3) The ratios of MWW/BW in interbout arousal have shown evident decrease compared with the entrance of hibernation after interbout arousal(p<0.05).4) The CS activity of SOL in hibernation is continuously increasing, and awaked 14 days after hibernation still showed higher level. The CS of EDL is no change and has a large decrease after hibernation. The LDH activity of SOL and EDL have no changes.5) The MHC of SOL of rat which underwent different numbers of simulating hibernation bout had slight transformation from theâ… toâ…¡compared with control rats (p>0.05), but the extent of the conversion was remarkable lower than the tail-suspension rat (p<0.05). Conclusion:1) The ratios of muscle wet weight to body weight (MWW/BW) of SOL and EDL, the activity of CS and the percentage of which underwent different numbers of hibernation bout didn't show difference. It indicates that hibernation bout, especially the stage of interbout arousal, is one of the mechanisms of anti-disuse atrophy in ground squirrel.2) The MHC of SOL of rat which underwent different numbers of simulating hibernation bout had slight transformation from theâ… toâ…¡compared with the tail-suspension rat. It can provide some thoughts for the physical therapy of anti-disuse atrophy.