Résumé
Objective To examine the effect of Caffeine on the cultured cortical neuron apoptosis in neonatal rats.Methods The primary cerebral cortex neurons for cultures were obtained from neonatal mice 2-3 days after birth,Caffeine reconstituted at final concentrations 300μmol/L and 1 000μmol/L was added to the cell cultures and continuously co-incubated for 6-36 h,respectively after the cortical neurons were continuously cultivated 7 days after incubation under temperature of 37℃ incubator with 5% CO_2 and 100% relative humidity,the intracellular calcium concentration,mitochondrial membrane potential and apoptosis rate were determined by the flow cytometry.The activity of Caspase-9 was assayed by enzyme-labeled instrument,and Caspase-9 activity by the enzyme-1inked analyzer.Cell morphological changes were observed under electron microscope and fluorescent microscope after being stained with Hoechst 33258 fluorescent dye.Results Compared with the control group,the average increase in intracellular calcium fluorescence intensity was most significant(P<0.05),which elevated from the normal value 43.13±2.02 to 45.28±1.16 and 46.92±1.99,respectively at 6 h;mitochondrial membrane potentials were reduced most significandy(P<0.05).from the base value 443.58 ±11.77 down to 289.53±16.47 and 165.14±14.72,respectively at 8h.Caspase-9 activity was peaked(P<0.05),from the normal value 1.00±0.000 to 5.33±1.02 and 8.33±0.92,respectively at 10 h.The neuronal apoptosis ratio was increased significantly (P<0.05),from the normal value 4.94±1.74 to 15.98±2.03 and 18.70±2.09,at 36h.The apoptotic bodies were observed at 24 h after administration of 300 μmol/L and 1000 μmol/L Caffeine.Conclusion Caffeine may promote neuronal apoptosis in neonate mice.