Mechanism of the influence of CPT1 on the proliferation of rat intestinal epithelial cells IEC-6 after 60Co γ-ray irradiation / 中华放射医学与防护杂志

ABSTRACT

Objective:To investigate the changes of CPT1A and CPT1B protein expression in rat intestinal epithelial cells (IEC-6) after 60Co γ-ray irradiation, and the mechanism of the influence of carnitine palmitoyltransferase 1 (CPT1) on the proliferation of irradiated IEC-6 cells. Methods:IEC-6 cells were cultured in serum-normal medium or in serum-starved medium overnight, and pretreated with 20 μmol/L palmitic acid (PA) before irradiation with 0, 5, 10, and 15 Gy. At 24 h after irradiation, the cellular protein was collected for the measurement of CPT1A and CPT1B proteins by Western blot. The influences of ETO, an inhibitor of CPT1, on the survival and proliferation of irradiated IEC-6 cells were analyzed by colony formation assay and CCK-8 assay. The protein expressions and phosphorylation levels of the extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK) in 5 Gy irradiated IEC-6 cells pre-treated with ETO were analyzed by Western blot at 48 h after radiation.Results:When IEC-6 cells were cultured in serum-normal medium together with PA, the protein level of CPT1A was significantly increased after 15 Gy irradiation ( t=-2.82, P<0.05). When IEC-6 cells were cultured in serum-starved medium, the protein level of CPT1A was significantly increased at 5, 10, and 15 Gy ( t=-3.28, -8.72, -8.67, P<0.05). When IEC-6 cells were cultured in serum-starved medium together with PA, the protein levels of CPT1A were significantly increased at 5, 10 and 15 Gy ( t=-10.69, -7.02, -8.23, P<0.05), the protein levels of CPT1B were significantly increased at 10 and 15 Gy ( t=-3.73, -5.05, P<0.05). After irradiation, the survival and proliferation of IEC-6 cells in ETO group were significantly lower than those in control group ( t=5.46, 13.22, P<0.05), and the protein level of ERK1/2 and p-JNK in ETO group were significantly lower than those in control group ( t=4.01, 3.29, 10.68, 14.44, P<0.05). Conclusions:CPT1 promoted radiation-induced IEC-6 injury cells survival and proliferation by enhancing the expression level of ERK1/2 protein and the activity of JNK.