No abstract

Cardiotoxicity is a life-threatening side effect of doxorubicin (DOX). Although the responsible mechanisms are largely unknown, it is demonstrated that DOX induces an elevation in the level of creatine kinase isoenzyme, lactic dehydrogenase, creatine phosphokinase, and troponin T in serum and reduces body/heart weight. In addition, cardiotoxicity is further confirmed by changes in ECG parameters and papillary muscle contractile force. Tropisetron is an effective antiemetic drug for chemotherapy-induced emesis. There is ample evidence that tropisetron exerts immune modulatory and anti-inflammatory properties. The present study was designed to investigate the protective effects of tropisetron pretreatment against DOX-induced cardiotoxicity in rats. In this study, DOX toxicity was induced by a single intraperitoneal injection (15 mg/kg), and in treated group, tropisetron (3 mg/kg; i.p) was administered 1 h prior to DOX injection. Our results indicated that tropisetron potently decreased body/heart weight loss and mortality rate and also improved ECG changes as well as heart contractility. In addition, tropisetron robustly counteracted the increase in the levels of serum biomarkers and alleviated the histopathological changes in rats' hearts as compared with the DOX group. Taken together, these results demonstrate that tropisetron has potent cardioprotective effects against DOX-induced cardiotoxicity.

The aim of this study was to develop a practical model of sciatic ischemia reperfusion (I/R) injury producing serious neurologic deficits and being technically feasible compared with the current time consuming or ineffective models. Thirty rats were divided into 6 groups (n = 5). Animal were anesthetized by using ketamine (50 mg/kg) and xylazine (4 mg/kg). Experimental groups included a sham-operated group and five I/R groups with different reperfusion time intervals (0 h, 3 h, 1 d, 4 d, 7 d). In I/R groups, the right common iliac artery and the right femoral artery were clamped for 3 hrs. Sham-operated animals underwent only laparotomy without induction of ischemia. Just before euthanasia, behavioral scores (based on gait, grasp, paw position, and pinch sensitivity) were obtained and then sciatic nerves were removed for light-microscopy studies (for ischemic fiber degeneration (IFD) and edema). Behavioral score deteriorated among the ischemic groups compared with the control group (p < 0.01), with maximal behavioral deficit occurring at 4 days of reperfusion. Axonal swelling and IFD were found to happen only after 4 and 7 days, respectively. Our observations led to an easy-to-use but strong enough method for inducing and studying I/R injury in peripheral nerves.

Tropisetron, a 5-HT3 antagonist receptor, is commonly used for the prevention of emesis following chemotherapy. Lines of evidence point to the anti-inflammatory and immune modulatory properties of tropisetron. The current study aims to investigate whether tropisetron is able to prevent the cardiotoxicity and neurotoxicity induced by doxorubicin (DOX) and vincristine besides its anti emetic effect in a co-administration protocol, since this combination therapy is widely used in various combination chemotherapy regimens. Jour n a l o f C linical T o x ic o log y