The Study On Sodium Gamma-hydroxybutyrate Enhance The Effects Of Radiotherapy On Rats

L~I~ The study on sodium gamma-hydroxybtityrate enhance the effects of radiotherapy on rats Abstract Objective: The effects and mechanism of sodium gammahydroxybutyrate (GLIB) on glioma treated with radiotherapy in rats were studied. Methods: The rat model of SHG-44 glioma (Suzhou Human glioma cell line) was built. The cell survival curve was measured by the clone forming assay to study its radiosensitivity. The pathological~ behavioral changes ~ SOD activity and LPO amount were determined to study the effects of GLIB on brain tissues.The expression of Caspase-3 mRNA and PCNA mRNA in glioma and brain tissues were measured by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) ,and the effects of GHB on brain tissues treated with irradiation was observed.The survival duration of the rats ~vith glioma was also observed by Cohort study. Results: The SHG-44 cells of glioma were radioresistant (Do~3.88Gy, Sf2=O.789) and the implanted rat model of glioma is practical and reliable. The potential doubling time (Tpot) and effective doubling time (Teff) measured by flow cytometiy (FCM) were 8.15 days 18.46 days respectively, and the Tpot became shorter after irradiation about 30 Gy, the glioma cells appeared quick regeneration. GHB could reduce obviously necrosis cell counts in CAl region of hippocanipus after irradiation with 6 Mev P -photon rays. G1-IB-I]F (hyperfractionated radiation therapy) could enhance the activities of SOD and decreased the contents of LPO (lipid peroxide) in the cerebrum .GHB æ¡°-IF also declined the expression of Caspase-3 mRNA in adjacent non-cancerous brain tissues, but not supressed the expression in the glioarns. The expression of proliferating cell nuclear antigen (PCNA) mRNA was significantly II suppressed in GI-IB-I-IF group. Especially, the survival duration of rats with glioina treated with GlIB-lIE was significantly longer, (MST = 39.60 days and controls =25.80 days, P<0.0l). Conclusion: The results demonstrated that sodium garnma-hydroxybutyrate could play an important role in improving the effects of radiotherapy on glioma Especially GHB-HF radiotherapy could reduce the extent of radiation damage of normal tissues and relieve the side effects of radiotherapy ,therefore prolonge the survival time of rats with glioma.