The Influence Of Hyperbaric Oxygen On Glioma Growth Research

BACKGROUNDS AND OBJECTIVES:As the most common tumor in brain, the most malignant glioma is glioblastoma with its five-year survival rate less than 10 % and average survival about 14.6months. Though surgery combining with chemo-radiotherapy makes great progress of glioma treatment, it just extends survival time 8 months.So the key factor in improving patient’s prognosis is how to cure glioma.Researchers think hypoxia as a key factor leads to resistance to chemo-radiotherapy. A report demonstrated that glioma cells under hypoxia could promote cell proliferation and inhibit apoptosis thus an increase of malignancy. So how to make an improvement on glioma hypoxia microenvironment is vital on patient’s prognosis.Hyperbaric oxygen(HBO) as a way to improve tumor hypoxia makes an effect through an increase of penetrability of the vessel thus enhances solubility of oxygen. Traditional, almost all the study showed HBO played an important role in glioma treatment. So, more knowledge about HBO will absolutely offer us new theory and make new therapy on glioma.METHODS:Part I:Change of cell number: Gl261 glioma cells cultured under normal pressure and normoxia, normal pressure and hyperoxia, hyperbaric oxygen 24 h, 48 h and 72 h and observe the change of cell number;Cell proliferation: Gl261 glioma cells cultured under normal pressure and normoxia, normal pressure and hyperoxia, hyperbaric oxygen and observe cell proliferation through CCK-8; those cells cultured under differentiated situation and then cultured normal pressure and normoxia and observe cell proliferatio;Cell apoptosis: Gl261 glioma cells cultured under normal pressure and normoxia, normal pressure and hyperoxia, hyperbaric oxygen and observe cell apoptosis through flow cytometry(FCM);Cell cycle: Gl261 glioma cells cultured under normal pressure and normoxia, normal pressure and hyperoxia, hyperbaric oxygen and observe cell cycle through flow cytometry(FCM);Glioma stem cells rate detection: Gl261 glioma cells cultured under normal pressure and normoxia, normal pressure and hyperoxia, hyperbaric oxygen and observe glioma stem cell rate through flow cytometry(FCM);Protein detection: Gl261 glioma cells cultured under normal pressure and normoxia, normal pressure and hyperoxia, hyperbaric oxygen and detected HIF1 a and caspase3 through Western-blot.Part II:C57 mice planted with GL261 cells fed under normal pressure and normoxia and hyperbaric oxygen, then observe survival rate and tumor volume through bioluminescence imaging(BLI);C57 mice planted with GL261 cells gave HBO after planted 0 day or 7th day and then observe survival rate;C57 mice planted with GL261 cells gave Nimustine Hydrochloride(ACNU) after HBO and observe survival rate.RESULTS:Under normoxia and normal pressure, GL261 glioma cell number showed an increase but a decrease under HBO or hyperoxia(<72h) and the number of cell under HBO decreased much more significantly than hyperoxia(P<0.05);The ability of proliferation under HBO or hyperoxia showed a decrease(P<0.05); the ability of proliferation after HBO or hyperoxia and then cultured under normoxia and normal pressure showed a decrease of cell proliferation(P<0.05);Apoptosis on HBO or hyperoxia was higher than normoxia and normal pressure situation(P<0.05);Cell cycle under HBO or hyperoxia showed an increase of G0/G1 state and a decrease of G2+S(P<0.05);The expression of CD133 and Nestin expressed higher after HBO or hyperoxia treatment(P<0.05);The expression of caspase3 showed an improvement but a decrease of HIF1a(P<0.05);There was no difference of C57 mice between those exposed HBO at 0 day after implanting and 7 day(P>0.05);HBO combining with ACNU increased effectiveness of ACNU and improved survival rate(P<0.05).CONCLUSION:HBO keeps glioma cells away from growth through promoting proliferation and cell cycle arrest. Because of the difference of microenvironment in vivo the influence about HBO on glioma varys from study in vitro.But sensitivity can be improved though combination HBO with ACNU.