BACKGROUND:More and more researches prove that cell apoptosis could be induced by glutamine, also there are more researches on studying the indirect and direct nervous-protective effects of insulin, but the nervous-protective effects of insulin on impairment induced by glutamine,as well as its mechanism still need further investigation. OBJECTIVE:To investigate the nervous-protective effects of insulin on impairment induced by glutamine in PC12 cells, and to explore its molecular mechanism. DESIGN:A prospective controlled study based on cells. SETTING:Department of Neurology,Zhejiang Hospital;Department of Neurology of Sun Yat-wen University Hospital. MATERIALS:The study was carried out at the Laboratory of the Third Affiliated Hospital and the Experimental Animal Center of Sun Yat-sen University from March 2002 to March 2003.PC12 cells were purchased from the same animal center. METHODS:Traumatic models were made in PC 12 cells by treated with 0.5 mmol/L glutamine for 20 minutes,and the insulin of different concentration were used for protection,after 24 hours,protective effects of insulin were assessed with MTT method,Hoechst33258 fluorescence staining,DNA agar gelatin electrophoresis,meanwhile the expression of PKB/Akt protein were also detected. MAIN OUTCOME MEASURES:①cell vitality;②abstraction of DNA and the results of agar gelatin electrophoresis;③the expression of PKB /Akt protein in experimental group.
RESULTS: The A value of 50 mU/L,100 mU/L,200 mU/L,400 mU/L insulin groups were 0.214±0.062,0.234±0.067,0.260±0.076 and 0.265±0.069,respectively,but the value of single glutamine group was 0.201±0.079,statistical analysis indicated that compared with single glutamine group, there were no significant difference in 50 mU/L,100 mU/L insulin groups(P >0.05),but 200 mU/L, 400 mU/L insulin groups were found statistically different from single glutamine group(t=-2.398, -2.716,P< 0.05);“DNA Ladder" could not be observed in 400 mU/L insulin group by electrophoresis;It was proved that Insulin could enhance the expression of PKB/Akt protein. CONCLUSION:Insulin has nervous-protective effects on impairment induced by glutamine in PC12 cells,furthermore it also has property of anti-apoptosis,and its protective mechanism might be associated with enhancement of the expression of PKB/Akt protein.