The Effect Of Different Temperature In Aerobic Exercise Induce Rats Myofiber’s Conversion

Objective:To establish a rat model of Different environme--ntal Temperature combination of aerobic exercise,after 8weeks,testing the right hind limbs of rat soleus muscle fiber types,extracting the MHC Ⅰ、MHCⅡa、MHCⅡb and MHCⅡx,and testing Each sample of succinate dehydrogenase and lactate dehydrogenase’s activity,Analysis under the different movem--ent environment temperature stimulation between aerobic exe--rcise on fast and slow fibers and the effect of mutual transfo--rmation between MHC.Provide theoretical basis for training athletes in the future,and provide some reference basis for the practice and research direction.Methods:Choose six weeks of healthy male SD rats,40,housed separately.Adaptive training three days,randomly divided into 4 groups:Quiet control group(QC,n=10),Low temperature(18± 2℃)swimming group(LC,n=10),Natural temperature(28±2℃)swimming group(LC,n=10),High temperature(38±2℃)swimming group(LC,n=10),10 of each group,LC,NC,HC swimming training Under the specified temperature,30 min each time,six times a week,training for eight weeks.In the process of experiment,the temperature controled by digital thermostat and LCD digital thermometer,24 h after the last training,take the right side of the soleus and the tibialis anterior muscle in rats,using ATP enzyme staining to identify muscle fiber types,isoforms of MHC were seParated into MHCI、MHCⅡa、MHCⅡb and MHCⅡx through SDS-PAGEelectrophoresis.Using colorimetry to detect the activity of LDH and SDH in the organization.Results:(1)after eight weeks,the weight of QC group was higher than LC and HC group,with significant difference(P<0.01),and the weight of NC group was obviously higher than LC group and HC group,with significant difference(P<0.01).(2)compared with QC group,NC and HC group soleus typeI and typeⅡmusclefiber number density are increased(P<0.01),and LC group’s type Ⅰ muscle fibers number density increases,with significant difference(P<0.01).compared with NC group,Type I muscle fiber density increase the number of LC group,with significant difference(p<0.01),type Ⅱ muscle fiber number density decreases(p<0.01),number of HC group’s type Ⅰ muscle fibers density increase(p<0.05).(3)compared with NC group,LC group soleus typeImuscle eare numberdensityare decreased(P<0.05).(4)compared with QC group,the NC group’s type Ⅰ muscle fiber density increase the number of the tibialis anterior muscle,(p>0.05),and LC group’s type Ⅰ muscle fibers number density increases(P < 0.01),and type Ⅱ muscle fiber number density decreases(p < 0.01).compared with NC group,Type I muscle fiber density increase the number of LC group,with significant difference(p<0.01),type Ⅱ muscle fiber number density decreases,with significant difference(p<0.01),HC group’s type Ⅰmuscle fiber number density increase,with significant difference(p < 0.01).(5)compared with QC group,the LC group’s type Ⅰ muscle eare density increase the number of the tibialis anterior muscle(p<0.01),and type Ⅱ muscle eare density decreased(p<0.01),HC group’s type Ⅰ muscle eare density increase(p<0.01).(6)compared with QC group,NC group of soleus MHC Ⅱ x % increased(p<0.05),NC group MHCI% increased,MHCⅡa% and MHCⅡb% reduced(p<0.01).HC group MHCI% and MHCⅡb% increased(p<0.05),MHCⅡa% and MHCⅡx% reduced(p<0.01).compared with NC group,LC group MHC Ⅰ% increased(p<0.01),MHCⅡa%,MHCⅡb% and MHCⅡx% reduced(p<0.01),with significant difference,HC group MHCI% and MHCⅡb% increased(p<0.05),MHCⅡa% and MHCⅡx% reduced(p<0.01).(7)compared with the QC group,tibialis anterior muscle of NC group’s MHCI% and MHCⅡa% increased(p<0.05),MHCⅡx% and MHCⅡb% reduced(p<0.05).LC group MHCI% and MHCⅡa% increased(p<0.01),MHCⅡx% and MHCⅡb% reduced(p<0.01).HC group MHCI% and MHⅡa% increased(p<0.01),MHCⅡx% reduced(p<0.01).compared with NC group,LC group MHC Ⅰ% increased(p<0.01),MHCⅡx% and MHCⅡb% reduced(p<0.01),with significant difference.HC group MHCI%,MHCⅡb% and MHCⅡa% increased(p<0.01),MHCⅡx% reduced(p<0.01).(8)the activity of LDH and SDH in the soleus of each group,have no significant difference(P>0.05),but the activit of LDH and SDH in tibialis anterior muscle of each group have significant difference,the activity of LC group compared with NC group and HC group,have significant difference(P<0.05).Conclusions:(1)groups of rat’s weight growth rate mainly presents the following trends:LC group<HC group<NC group<QC group.(2)training underlow temperature conditions can make rat skeletal muscle fiber types change eare density,Training under low or high temperature environment can make rat skeletal muscle fiber types change number density.(3)training under different temperature conditions can Initiate changes in rat skeletal muscle MHC subtype,Training under low temperature makes MHCⅡx%,MHCⅡb% turns to MHCI%、MHCⅡa%,and training under high temperature makes MHCⅡa%、MHCⅡx% turns to MHC Ⅰ%.(4)under the condition of low temperature,the activity of SDH and LDD in muscle tissues have obvious inhibitory effect.