Effects Of Living High/Training Low On Hepatic Apoptosis Regulatory Gene And Proliferation In Rat Liver

Most previous studies have expressed that anoxia appearance in hypoxia,exercise and hypoxic training can impel apoptosis directly or indirectly.The occurrence of the cell,proliferation,differentiation and cell death kept close.The occurrence or influence of apoptosis and proliferation appeared differently in different hypoxia or oxygen cent (altitude),hypoxic time and stimulate ways.This research tries to study the effects living high/training low on the relation or connection between apoptosis and proliferation,HIF-1a and apoptosis related gene,and the complexion of apoptosis related gene,to provide research data for the application of a medium and practice science about hypoxic training.Methods:60 male SD rats(Hunan Agricultural University supplied, licence number:XIANG scxk 2003-003)were randomly divided into six groups:control group(C,n=10),8h hypoxic exposure group(8hHE, n=10),12h hypoxic exposure group(12hHE,n=10),purely training group(T,n=10),8h Living High-Training Low group(8Hilo,n=10) and 12h Living High-Training Low group(12Hilo,n=10).Group C didn' t hold hypoxia and training.Groups HE and Hilo were held in hypoxia chamber(12.5%concentrations of oxygen,simulated as a altitude of 4000m)with 8h and 12h each day,5 days per week for 4 weeks.Groups T and Hilo were trained at the speed of the 25 ms/min for 1 hour each day,5 days per week for 4 weeks.After sentencing to death,the blood routines were assayed from the serum and the hepatic glycogen content and hepatic mitochondrial Ca²⁺concentration were assayed from hepatic homogenates.The liver cell configuration was detected in paraffin sections by HE normal regulations dyeing.Apoptosis was detected in paraffin sections by the TUNEL technique.The apoptotic cell nucleus was observed by microscope after paraffin wax slice dyeing.Immunohistochemical and computer image processing technique were applied to detect positive expression and quantificational analysis for HIF-1a,bax,bcl-2 and PCNA protein.Results:(1)Rats weight presentd growth with lengthways(p＜0.05), but each group weight didn't change evidently with the horizontal experiment time.(2)As compared with group C,WBC increased significiently in group T(p＜0.01).As compared with group T,WBC decreased in group Hilo(p＜0.05),and didn't change between group 8h and 12h Hilo.The indexes of WBC,Lymph and Mid is similar to Gran variety trend,expose horary extension to present to descend trend along with hypoxia time.(3)HE dyeing shows that there demonstrated clearly red dyeing liver apoptotic cells in group T.This research demonstrated clearly more and more red dyeing apoptotic cells in Hilo groups.And this research demonstrated cell swells and cleft enlarges obviously in liver cells.(4)As compared with group C,the index of apoptosis increased significantly in other experimental groups(p＜0.01).The index of apoptosis occurred significantly in group Hilo more than HE and T (p＜0.01).But with the following hypoxic time,the index of apoptosis has none-significience in group HE and Hilo.(5)As compared with group C,the hepatic glycogen contents showed significience in each group (p＜0.05).Glycogen contents presented debasement along with hypoxia time in group Hilo.And glycogen contents in Hilo 12h group were lower significient than Control group(p＜0.01).This research demonstrated the correlation(r=-0.147)between apoptosis and glycogen contents.(6) As compared with group C,hepatic mitochondria Ca²⁺concentration show significience in each group(p＜0.05).Hepatic mitochondria Ca²⁺ concentration presents debasement along with hypoxia time in group HE. And there is less mitochondria Ca²⁺concentration than group C(p＜0.05). The hepatic mitochondria Ca²⁺concentration in group T were thicker 197%than in group C(p＜0.01).Hepatic mitochondria Ca²⁺concentration presents debasement along with hypoxia time in Hilo,and obviously lower than group T(p＜0.05).This research demonstrated the correlation (r=0.176)between apoptosis and mitochondria Ca²⁺concentration.(7) Bax protein expressed in spite of groups HE,group T and groups Hilo (p＜0.05).Bax protein in group 8hHE expressed slightly lower than group 12hHE.Bax protein in groups Hilo expressed higher than groups HE(p＜0.05),and higher in group T too(p＜0.05).Bax protein presents ascend along with hypoxia time in groups Hilo.This research demonstrated the correlation(r=0.693,P＜0.01)between apoptosis and bax expression.(8)As compared with group C,bcl-2 protein demonstrated significant in each experimental group(p＜0.05).Bcl-2 protein presents the ascend trend along with hypoxia time in groups HE. And bcl-2 protein in groups HE expressed higher than group C(p＜0.05), bcl-2 protein presents debasement along with hypoxia time in groups Hilo. But it was still significient higher than group C(p＜0.05).(9)The liver tissue bax/bcl-2 value demonstrated that it was prominent significience in 12h Hypoxia and Hilo 12h group(p＜0.05).As compared with group T, bax/bcl-2 show prominent significience in groups Hilo(p＜0.05).(10) HIF-1a protein expressed in spite of groups HE,group T and groups Hilo (p＜0.05).HIF-1a protein in 8hHE group expressed slightly lower than group 12hHE.As compared with group HE,HIF-1a protein ascended in groups Hilo(p＜0.05).As compared with group T,HIF-1a protein ascended significiently in groups Hilo(p＜0.05).This research demonstrated the correlation(r=0.770,p＜0.01)between apoptosis and HIF-1a.This research demonstrated the correlation(r=0.770,p＜0.01) between HIF-1αand bax.(11)PCNA protein presents debasement along with hypoxia time in group HE.And as compared with group C,it showed that it was prominent significience in group HE(p＜0.05).PCNA protein in group 12hHE expressed obviously lower than group 8hHE (p＜0.01).As compared with group C,HIF-1a protein expressed slightly ascend in spite of groups HE,group T and groups Hilo.And as compared with groups HE,it showed that it was prominent significience in groups Hilo(p＜0.01).This research demonstrated the correlation(r=0.436, p=0.009)between apoptosis and PCNA.Conclusions:(1)There were liver apoptosis in purely training,hypoxic exposure and Hilo(12.5%concentrations of oxygen,simulated as a altitude of 4000m).This research demonstrated that apoptosis occurred significiently in different hypoxic time.Liver apoptosis occurred in group 12hHE and 12Hilo more than in group 8hHE and 8Hilo.(2)Rat economy cannot adapt(for example:HGB,RBC and WBC decreased,Ca²⁺concentration in cytoplasm loaded,glycogen decreased, bax/bcl-2 increased,and then promote liver apoptosis)when hypoxic exposure and(or)training in Hilo stimulate too heavy and long.(3)Bax,bcl-2 and HIF-1a gene participates to adjust liver apoptosis.HIF-1αprotein may adjust bax and bcl-2,and it's related with bax prominently,HIF-1αpromotes bax protein expression to induce liver apoptosis.(4)This research demonstrated the significant correlation between apoptosis and glycogen contents,between apoptosis and mitochondria Ca²⁺concentration.(5)It was maybe a important factor to cause liver apoptosis for white blood cell bolting in circulation.(6)There were liver proliferation in hypoxic exposure,purely training and Hilo.It showed there was different appearance with different hypoxia time in hypoxic exposure and Hilo.Proliferation increased significant after training intervention.Training avail liver cells to renewing.This research demonstrated correlativity between liver apoptosis and proliferation.It's important to keep a dynamic equilibrium between liver apoptosis and proliferation.