The Expression Of Hypoxia And Training In Skeletal Muscle Apoptosis Of Rats

We examined the effect of hypoxic exercise to rat's oxygentransportation ability and skeletal muscle tissue apoptosis,and we also examined, the effect to skeletal muscle apoptosis,which could provide an experimental records to scientificguidance of exercisers' hypoxic exercise.We take 60 male SD rats, which are randomly distributed to6 groups, 10 rats each, which are normal contrast group (GroupA), hypoxia 8-hour group (Group B), hypoxia 12-hour group(Group C), training contrast group (Group D), hypoxia 8-hourtraining group (Group E), hypoxia 12-hour training group (GroupF). Group D, E, F take 1 hour treadmill training in the rateof 25m per min in normal oxygen environment. On 8 o'clock nextmorning, we put B, C, E and F group into hypoxia cabin, oxygenconcentration is 12.5% (equal to 4km height), 8 and 12 hourslater (16 and 20 o'clock on the same day), put group B, E andC, F into normal oxygen concentration environment separately.This training lasts 4 weeks, and 5 days each week. 24 hours afterthe last training to death, we take 3ml fresh blood, using bloodcell analysis to measure RBC, Hct and Hb. We also take soleus musoletissue, proceeding with fixing and tissue embedding, usingimmunohistochemistry and TUNEL to measure Bax, Bcl-2, HIF-1α and apoptosis index.Results: (1)Blood cell: The RBC, Hct and Hb of traininggroup compared with no-training group reduce(P＜0.01); As thehypoxic time prolong, hypoxia 0-hour group, hypoxia 8-hourgroup and hypoxia 12-hour group raised one by one(P＞0.05);When the hypoxia and training effected at the same time, hypoxia0-hour training group, hypoxia 8-hour training group andhypoxia 12-hour training group raised one by one(P＜0.01).(2)HE: By morphologic observation, the mose obvious chang onewas Group D, the other were Group C, Group E, Group F, GroupB and Group A. (3)TUNEL: Skeletal muscle tissue of traininggroup compared with no-training group, apoptosis indexevidently increase; Increasing the duration of hypoxic period,hypoxic stimulus made the apoptosis index of skeletal muscletissue increase; In the hypoxic training groups, as the hypoxictime prolong, apoptosis index would decrease. (4)Immunohistochemistry: skeletal muscle tissue of training groupcompared with no-training group, Bax and HIF-1αevidentlyincreaseBcl-2/Bax, bcl-2 and Bcl-2/Bax decrease(P＜0.01);hypoxic stimulus made the Bax of hypoxia 0-hour training group,hypoxia 8-hour training group-and hypoxia 12-hour traininggroup increased one by one(P＜0.01), HIF-1α, bcl-2 and Bel-2/Bax decreased one by one(P＜0.01); When the hypoxia andtraining effected at the same time, theBax and HIF-1αhypoxia0-hour training group, hypoxia 8-hour training group andhypoxia 12-hour training group reduced one by one(P＜0.01),bcl-2 and Bcl-2/Bax increase(P＜0.01).Conclusion:1) nypoxic exercise enhanced rat's ability of oxygentransportation, and the enhancement increases with thelasting of hypoxic exercises.2) Increasing the duration of hypoxic period, hypoxic exercisetraining decrease the apoptosis of cells in rat's skeletalmuscle tissue, which protects the nerves.3) In the hypoxic exercise, due to the change of body'sadaptability to hypoxic stimulus. After exercise, thedamage to skeletal muscle tissues also decrease.4) In hypoxic exercise, HIF-1αtake part in the adjustment toskeletal muscle apoptosis.