THE EVALUATION OF MEMBRANE LIPID PEROXIDATION ON CARDIAC TISSUES DUE TO THE USE OF PACLITAXEL AND THORACAL RADIOTHERAPY, SIMULTANEOUSLY, IN RATS

Purpose: The invastigation of cardiac toxicity in rats, through membrane lipid peroxidation (LP), caused by the external thoracal radiation (RT) and paclitaxel (Tx) administered simultaneously or separately. Material and Methods: 120 rats were grouped as RT, Tx, RT+Tx and control groups. Radiotherapy was given to left hemitorax 1x20 Gy and Tx 20 mg/kg intraperitonealy. After 24 hours, 72 hours and 100 days LP was evaluated in cardiac tissue by measurement of levels of malondialdehide (MDA). Differences between groups were compared with Varians analysis, Fisher PLSD test was used as post Anova test. Results: Compared with control group, the highest level of MDA was seen in Tx group at 24 hours (P<0.01). RT+Tx group at 72 hours (P<0.001) and RT+Tx group at 100 days (P<0.05). Level of MDA was not significantly different from control group, in RT and RT+Tx group at 24 hours and RT and Tx group at 72 hours. Conclusion: In Tx group, the rising level of MDA at 24 hours, fall down to normal levels of control group at 72 hours and this was explained by repair. But at 72 hours, the level of MDA was high in RT+Tx group and after 100 days again the level of MDA was high in RT+Tx group and this was explained by the fact lipid peroxidation caused by radiation cannot be repaired in the presence of simultaneous paclitaxel administration.