High resolution proton nuclear magnetic resonance (1H NMR) spectroscopy of surviving C6 glioma cells after X-ray irradiation.

PURPOSE To study biochemical response of living model of glioma to X-rays irradiation using high resolution proton nuclear magnetic resonance (1H NMR) spectroscopy. MATERIAL AND METHODS Rat glioma C6 cells were irradiated with 3.8 Gy (D0, the 37% clonogenic survival dose) of X-rays from a teletherapy unit at the dose rate 8.8 Gy/min. After irradiation the cells were incubated at 37°C/5%CO2/95%O2 for various period of incubation (24, 48, 72 and 96 hours) in the fresh medium. The high resolution 1H NMR spectra of the agarose-cell mixtures (2 x 10(7) cells/ml) were acquired using a Varian Inova-300 multinuclear pulsed NMR spectrometer operating at the 1H resonance frequency of 300 MHz. The mean spectra were obtained as the averages of six independent measurements. RESULTS The statistically significant increase in the CH2/CH3 lipid signals ratio in the C6 cells after irradiation with 3.8 Gy dose and incubation for 24-96 h was observed. CONCLUSIONS Our method of the sample preparation enables the metabolic effects of irradiation to be observed in viable cells, which can effectively support the identification of the spectroscopic changes in vivo. Application of the gel suspensions in the NMR studies has advantages over the usual liquid suspensions in terms of improved reproducibility of the data and cell viability, with no net loss of the spectral quality.