Effects Of Acute Hypoxia On Apoptosis Of Brain And Kidney In Mandarin Voles And Brandt's Voles

Oxygen is an important substance in the life activities of most animals.Environmental hypoxia could cause oxygen deficiency in body tissues,which could lead to apoptosis,tissue injury,and even death.In their long term underground lives,subterranean rodents have evolved adaptions to the hypoxic environment both in behavioral and physiological.Mandarin voles(Lasiopodomys mandarinus)is a subterranean rodent,which lives in the underground tunnel system for a long time,and exposed to hypoxia and dark environment.This research used comparative biology to research the differences in behavior,apoptosis,HIF-1? and p53 gene's expression between Mandarin voles and Brandt's voles(L.brandtii).Acute hypoxia environments were simulated in the oxygen chamber in laboratory.The aims of this research were to explore the adaptation mechanism in behavior,physiology and molecular to hypoxia,which could provide a reference to the adaptation research of hypoxia,also enhanced the understanding and knowledge of the adaptation of subterranean rodents to hypoxia.Main results are as follows:(1)Influences of hypoxia on Mandarin voles and Brandt's voles' behavior: 1)Behavior adaptation of Mandarin voles and Brandt's voles' were similar,and there were no significant differences in resting,grooming,locomotion,leaning and escaping behavior between them.2)Mandarin voles were more adaptive to light hypoxia(15% oxygen concentration),and shown more movements and exploratory behavior,this may relate to the oxygen concentration in the natural subterranean tunnels;3)Moderate hypoxia(10%)and severe hypoxia(5%)both restrain the behavior of Mandarin voles and Brandt's voles,and neither of the two rodents adapt to these two oxygen concentrations.4)The peak of Mandarin voles' moving-behavior appeared in 15% oxygen concentration,not normal oxygen concentration;The moving-behavior of Brandt's voles decreased with the oxygen concentration' reduction,this trend was the general pattern of ground animals.(2)Effects of hypoxia on brain and kidney apoptosis of Mandarin voles and Brandt's voles: 1)There were no significant differences of brain apoptosis between Mandarin voles and Brandt's voles.Interactions lied in between rodents and reoxygenation time.During reoxygenation,brain apoptosis rate of Mandarin voles decreased gradually,but Brandt's voles' changes were not significantly;2)The kidney cortical' apoptosis rate of Mandarin voles were significantly lower than Brandt's voles,and there was an interaction between rodents and reoxygenation time.During rexoygenation,neither the kidney apoptosis rate of Mandarin voles and Brandt's voles changed significantly.(3)Effects of hypoxia on brain and kidney HIF-1? and p53 genes' expression in Mandarin voles and Brandt's voles: 1)There were no significant differences between HIF-1? gene's expression in the brains of Mandarin voles and Brandt's voles,there were no interactions between rodents and the time of reoxygenation;There was a higher expression level of HIF-1? gene in 0h of reoxygenation,then decreased rapidly.2)The p53 gene's expression of Mandarin voles and Brandt's voles had no significant difference,and there were no interactions between rodents and reoxygenation time.During reoxygenation,the p53 gene's expression level in both rodents' brains significantly decreased and did not return to the normal level after 24 h of reoxygenation.3)There were no significant differences in the expression level of HIF-1? gene in the kidney of Mandarin voles and Brandt's vole.And there were no interactions between kinds of two rodents,the expression level of HIF-1? gene was higher at 0h of reoxygenation,and then decreased rapidly.4)The p53 gene's expression level in kidney of Brandt's voles is significantly higher than Mandarin voles.There were no interactions between rodents and reoxygenation time.The p53 gene expression level of both rodents were decreased,and failed to return to normal level after 24 h of reoxygenation.Main conclusions were as follows:1)Mandarin voles had a good adaptation to light hypoxia and had a more active behavior than Brandt's voles.The activity of Brandt's voles decreased when the oxygen concentration decreased.2)Severe hypoxia could cause serious brain apoptosis in Mandarin voles and Brandt's voles.Mandarin voles could rapidly repair apoptotic cells.Apoptosis in kidney of Brandt's voles is significantly higher than that of Mandarin voles,both of them repaired slowly.3)Severe hypoxia could significantly increased HIF-1? gene expression level in brain and kidney of Mandarin voles and Brandt's voles,and this level decreased to the normal level during the next 24 hours.But the expression level of p53 gene decreased,and did not return to normal levels after 24 hours of reoxygenation.