Study On The Effects Of Taurine On The Cycle Of The Irradiated Cells And The Mechanism Of Taurine's Radioprotection

Taurine (Tau) , a ? -amino acid containing sulphur, is vital free acid in the body and perform various biological effects. To investigate the radioprotective effects of Tau, different concentrations of Tau were added in advance to the cell cultures in vitro and the different groups were irradiated by 15Gy ?-rays. Methods: 1) 12h after irradiation, the cell cycle of NIH3T3 cells was determined by flow of cytometry and the ratio of alternations in P16 gene exon-2 was evaluated through PCR-SSCP. 2) The content of MDA, the activities of the SOD and GSH-Px in the supernatant of NIH3T3 cells and the cells were measured by detecting kits immediately after irradiation. 3) The level of matrix metalloproteinase-2 (MMP-2) in Hela cells was detected by western-blotting and dot-blotting 2h after irradiation. Results: 1) Compared with the positive control groups, the percentage of G1 phase in Tau-groups was increased while the percentage of G2 phase in Tau-groups was reduced significantly (P<0.05); The ratio of alternations in P16 gene in the Tau-groups was less than that in the positive control groups. 2) The content of MDA either in cells or cells' supernatant in Tau-groups declined markedly in comparion with the positive control groups (P<0.05) and the activity of SOD and GSH-Px in cells'supernatant ascended greatly (P<0.05 and 200mg/L P<0.01). 3) The level of MMP-2 in the Tau-groups after irradiation was less than that of in the positive groups. Conclusion: The results suggest that adequate concentration of Tau may affect the cell cycle of NIH3T3 cells after irradiation and hinder the damaged cells from getting though the G1 checkpoint; There seems to be certain mechanisms by reduction of damages in some tumor suppressors (for example P16 gene) occured. Tau appears to have enhanced the ability of cells to eradicate the radicals and protected cells from membranes and DNA damages induced by irradiation. There is a good evidence that Tau inhibited the high expression of MMP-2 induced by irradiation to prevent the cell migration and invasion.