Gene Expression Of Bax,Bcl-2and Ca²⁺ Concentration In Gastrocnemius Muscle Of Daurian Ground Squirrels During Hibernation

Objective:1. To determine the Ca2+concentrationin gastrocnemius muscle fiber on ground squirrels,study the effection of disuse on hibernator at the level of cytosolic calcium, and further study the possible mechanisms of anti-muscle atrophy of tetramethylpyrazine.2. To determine the SDH activity of gastrocnemius muscle on ground squirrels,study on effect of disuse on hibernatorr at the level of oxidative capacity, and further study the possible mechanisms of anti-muscle atrophy of tetramethylpyrazine.3. To determine the relative expression level of Bax mRNA and Bcl-2mRNA of gastrocnemius muscle on ground squirrels, and further study the possible mechanisms of anti-muscle atrophy of tetramethylpyrazine at the level of cell apoptosis.4. To determine the Ca2+concentration,SDH activity and relativeexpression level of Bax mRNA andBcl-2mRNAin gastrocnemius muscle fiberon Hindlimb unloading rats, study the possible mechanisms of disuse atrophy and anti-muscle atrophy of tetramethylpyrazine.Methods:1. The concentration of Ca2+in gastrocnemius muscle fiber was determined by laser scanning confocal microscope.2. The activity of SDH was determined byUltravioletspectrophotometer.3. The relative expression of Bax mRNA and Bcl-2mRNA of gastrocnemius muscle was determined by real-time fluorescent quantitative PCR technique.Results:1. Compared with pre-hibernation group, the concentration of Ca2+in gastrocnemius muscle fiber increased by49.0%(P<0.05) and196.4%(P<0.01) respectively in the hibernation group and the interbout arousal group.Compared with hibernation group,the concentration of Ca2+increased by99.0%(P<0.01) in interbout arousal group. Compared with interbout arousal group, the concentration of Ca2+decreased by164.5%(P<0.01) in post-hibernation group.2. Compared with pre-hibernation group, the SDH activity in hibernation group、 interbout arousal group and post-hibernation group increased by46.1%、49.1%and34.5%(P<0.01) respectively.3. Compared with pre-hibernation group, the relative expression of Bax mRNA and Bcl-2mRNA increased by47.6%and80.5%(P<0.05) respectively in the hibernation group, the relative expression of Bax mRNA and Bcl-2mRNA increased by56.0%and83.2%(P<0.05) respectively in the interbout arousal group,but the relative expression of Bax mRNA/Bcl-2mRNA ration decreased by22.2%(P<0.05) in post-hibernation group.Compared with hibernation group, the relative expression of Bax mRNA decreased by27.7%(P<0.05) in the post-hibernation group. Compared with interbout arousal group, the relative expression of Bax mRNA decreased by33.3%(P<0.05).4. After14-day hindlimb unloading, the concentration of Ca2+in gastrocnemius muscle fiber increased by189.6%(P<0.01),compared with hindlimb unloading rats,the concentration of Ca2+in gastrocnemius muscle fiber decreased by119.3%(P<0.01) in HLU+Tmp group.5. After14-day hindlimb unloading, the SDH activityin gastrocnemius muscle dcreased by24.3%(P,0.05), but HLU+Tmp group was not significant.6. After14-day hindlimb unloading, the relative expression of Bax mRNA and Bcl-2mRNA increased by140.1%and70.9%(P<0.01) respectively,and the relative expression of Bax mRNA and Bcl-2mRNA in HLU+Tmp group were increased106%(P<0.01) and42.3%(P<0.05) respectively, the ration of Bax mRNA/Bcl-2mRNA in HLU+Tmp group were increased37.5%(P<0.01).Tthe relative expression of Bax mRNA and Bcl-2mRNA in HLU+Tmp group were decreased by14.2%and16.7%comparing with hindlimb unloading group,but were not statistically significant (P>0.05).And the ration of Bax mRNA/Bcl-2mRNA in HLU+Tmp group were increased37.5%(P<0.01). And the ration of Bax mRNA/Bcl-2mRNA were increased42%(P<0.01).Conclusion:1. The concentration of Ca2+gradually increased during hibernation, and the interbout arousal group was the highest, but in post-hibernation groupof the gastrocnemius Ca2+recovery to pre-hibernation levels, interbout arousal may be one of anti-muscle atrophymechanism.2. The activity of SDH increased during hibernation, and increased oxidative metabolism may be one of anti-muscle atrophy mechanism.3. During the hibernation,the relative expression of Bax mRNA and Bcl-2mRNA increased,but the anti-apoptosis gene far outweigh the pro-apoptosis gene.During hibernation elevated anti apoptosis gene Bcl-2may be the important mechanism of anti-against atrophy.4. After14-day hindlimb unloading,the concentration of Ca2+in gastrocnemius muscle fiber increased, oxidative capacity decreased,and gastrocnemius muscle will appear apoptosis phenomenon,ligustrazine can inhibit hindlimb cytoplasmic calcium overloading load generated by the. Tetramethylpyrazine can suppress the intracellular calcium ion overloading.