Simulated Altitude Training And Recovery On Rat Kidney Histological Study

Objective:To explore the effect and the possible mechanism of Simulated Altitude Training and recovery methods on rat renal tissueMethods:Select 32 healthy male SD rats aged 8 weeks, Rodents with a national standard diet,Conventional sub-cage farming, free food, natural lighting, animal laboratory temperature of 20℃to 24℃, humidity ranged from 30% to 60% during the spacious adaptability keeping the experiments,we sterile the animal room and cages and water cattle before experiment. The density of normal pressure-hypoxia room is 12.5%-12.7%,in relative altitude 4000m.Simulated Altitude Training:male SD 32 rats were divide randomly into normal oxygen control group,normal oxygen exercise group,hypoxia control group,hypoxia exercise group.In a hypoxia of 12.7% and relative altitude of 4000m animal room,treadmill grad is 10 degree and speed is 20m/min. The whole experiment of hypoxia control group and hypoxia exercise group are in hypoxia condition.In every week, training comes up to five days with two days'rest. Specific training methods are as follows:On the first two days of the first week, the treadmill speed is 20m/min and running lasts for 10mins, after one day's rest, from Thursday to Saturday, the treadmill speed is 20m/min and running lasts for 15mins and then rest on Sunday; On the first two days of the second week, the treadmill speed is 20m/min and running lasts for 20mins, after one day's rest, from Thursday to Saturday, the treadmill speed is 20m/min and running lasts for 25mins and then rest on Sunday; On the first two days of the third week, the treadmill speed is 20m/min and running lasts for 30mins, after one day's rest, from Thursday to Saturday, the treadmill speed is 20m/min and running lasts for 40mins and then rest on Sunday; On the first two days of the fourth week, the treadmill speed is 20m/min and running lasts for 50mins, after one day's rest, from Thursday to Saturday, the treadmill speed is 20m/min and running lasts for 60mins and then rest on Sunday.IHT and recovery:Male SD 64 rats were divide randomly into 8 groups:hypoxia control group,exercise immediate group; nomal recovery 24h group; hypoxia recovery 24h group; nomal recovery 48h group; hypoxia recovery 48h group; nomal recovery 7d group; hypoxia recovery 7d group; In a hypoxia of 12.7% and relative altitude of 4000m animal room, the rats freely move and eat in according surrounding. The rats were exercised on the treadmill only one time, exercise 3min, rest 3min,10 times, the recovery plan began immediately afer the 10th group. The treadmill grad is 10 degree and speed is 20m/min. After experiment the animals of each group were dealt with intraperitoneal injection of anesthesia, dissect,quickly harvested two kidneys. By HE,Masson VG and Silver staining with ammonium acetate, technology on the Renal tissue, We can observe the renal medulla and cortex tissue structural changes. By immunohistochemical techniques on the Renal tissue we can find the different expressions of Bax, Bcl-2, p53, PCNA, HIF-la, VEGF, NOS, TNF-a and HSP70 and compare the expressions. All data using Leica microscopic imaging system captures images and Immunohistochemistry using Image-Pro Plus 5.1 image processing software integral optical density analysis.1 Simulated altitude training can promote expression of p53 and Bax in renal tissue, inhibit expression of Bcl-2 to different degrees, so that the ratio of Bax/Bcl-2 increased Tip:simulated high altitude training can promote apoptosis of kidney cells.2 Simulated altitude training can significantly promote expression of iNOS, inhibit synthesis of nNOS and eNOS to different degrees, suggesting that simulated high altitude training can maintain the kidney's physiological function by synthetic expression of nNOS and eNOS, and by significantly enhanced expression of nNOS make the organizations produce excessive NO, which can lead to cells apoptosis.3 Simulated altitude training can promote the expression of HSP70 and TNF-a, suggesting that over-expression of HSP70 promoted by simulated high altitude training indicate that simulated altitude training can cause more cell damage and increase apoptosis; simulated altitude training can promote the over-expression of TNF-a suggesting that simulated altitude training lead to aggravation of the inflammation of renal tissue.4 Simulated altitude training can promote the expression of HIF-1a, VEGF, and PCNA in kidney tissue, suggesting that simulated high altitude training can promote the proliferation of kidney cells, leading to proliferation and hypertrophy of glomerular. Simulated altitude training can significantly enhance the overexpression of HIF-la and VEGF,which make HIF-la promote the expression of Bax and VEGF and lead to the aggravation of cells apoptosis in kidney's issue as well as the increase of glomerular filtration membrane permeability. All of those mentioned above probably can contribute to the abnormal urinary components of athletes after simulated altitude training.5 The expressions of Bax, p53 and Bax/Bcl-2 ratio in renal tissue under normal oxygen conditions are lower than under low oxygen conditions. Hypoxic training can raise the expressions of p53 and Bax and the Bax/Bcl-2 ratio. The expression of Bcl-2 under normal oxygen conditions is higher than under low oxygen conditions.The general trend of the expressions of p53 and Bax and the Bax/Bcl-2 ratio develop similarly. Low oxygen can lead to more significant apoptosis increase than normoxia recovery. Apoptosis reaches its highest under both normal oxygen and hypoxic conditions in 48h. The best time of normal oxygen recovery is after 24h; the best time of hypoxia recovery is after 48h, and normal oxygen conditions is better than hypoxic conditions for recovery.6 Hypoxic training can lower the expressions of nNOS and iNOS, increase the expression of eNOS as well as the cNOS/iNOS ratio. Compared with normoxia,the expression of nNOS under hypoxia is lower yet the expressions of iNOS and eNOS are higher,the cNOS/iNOS ratio under hypoxia is lower.So hypoxic conditions can promote the expression of NOS and the excessive NO can cause apoptosis increase. It can indicate that normal oxygen conditions is better than hypoxic conditions for recovery and the best time is after 24h.7 Hypoxic training can lower the expression of TNF-a, increases the expression of HSP70; In hypoxia and normoxia recovery, changes of TNF-a and HSP70 tend to increase first and then decrease. The expressions of TNF-a and HSP70 in hypoxic conditions are higher than normoxia. Hypoxic training can be used to lower the expression of TNF-a and increases the expression of HSP70 so as to protect kidney cells,and make renal functions meet the hypoxia training needs. Proinflammatory reaches its peak in24h and damage is most severe in 48h on normoxia.Compared with normoxia, Proinflammatory and damage are more significant in hypoxic conditions. Normal oxygen conditions is better than hypoxic conditions for recovery and the best time of recovery is after 48h.8 Hypoxic training can decrease the expressions of PCNA and VEGF, increase expression of HIF-1α.In hypoxic conditions,the expressions of VEGF and HIF-1a are lower and the expression of PCNA is higher than in normoxic conditions. It is possible that in the process of restoration of normal oxygen a large number of free radicals are produced which further damage kidney; the overexpression of PCNA may be associated with renal interstitial tissue repair and proliferation.Conclusions:Simulated altitude training can increase inflammatory reaction and Induce kidney damage through the double stimulus of hypoxia and training. meanwhile, it can lead to glomerular hypertrophy and renal glomerular basement membrane thickening by promoting cell proliferation in kidney tissue, so that it can increase apoptosis of kidney cells. Intermittent hypoxic training can cause kidney damage, damage in the recovery process first increases and then decreases, In the recovery after simulated altitude training, proinflammatory proliferation and damage are more significant in hypoxic conditions compared with normoxia, apoptosis of kidney tissue increase. The injury caused by the movement is delayed and the recovery is closely related with the time.