Aim
Malignant glioma is a rapidly progressive primary brain cancer. The aim of the study was to investigate the effect of far-infrared ray (FIR) on temozolomide (TMZ)-treated glioma in rats. Materials and
Conclusion
FIR might increase the growth of glioma under TMZ treatment in rats possibly via increasing VEGF expression, but not HIF-1α expression.
Methods
Male, 8-week old, Fischer 344 inbred rats with glioma were randomly divided into three study groups (20 rats in each group). The control group received saline only once daily for 5 days. The TMZ group received TMZ (30 mg/kg) once daily for 5 days. The TMZ plus FIR group received TMZ (30 mg/kg) once daily for 5 days and infrared-c irradiation of 40 min twice daily for 4 weeks. The relative tumor fold and the expression of hypoxia-induced factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) were compared using one-way ANOVA at the end of study.
Results
The relative tumor fold of the TMZ+FIR group was significantly higher compared to the control group, and was borderline higher compared to the TMZ group at Day 7. The relative tumor fold of TMZ+FIR group was significantly higher compared to the control group and the TMZ group at Days 14, 21 and 28. HIF-1α expression of TMZ+FIR group was borderline higher compared to the control group at Day 28. The VEGF expression of TMZ+FIR group was significantly higher compared to the control group and the TMZ group at Day 28.