Evaluation of differential representative values between Chinese hamster cells and human lymphocytes in mitomycin C-induced cytogenetic assays and caspase-3 activity.

Chinese hamster ovary (CHO) cells, its lung fibroblasts (V79), and human lymphocytes are routinely used in in vitro cytogenetic assays, which include micronuclei (MN), sister chromatid exchange (SCE), and chromosome aberration (CA) assays. Mitomycin C (MMC), a DNA cross-link alkylating agent, is both an anticancer medicine and a carcinogen. To study the differential representative values of cell types in MMC-treated cytogenetic assays and its upstream factor, cysteine aspartic acid-specific protease (caspase)-3. Among the chosen cell types, lymphocytes expressed the highest sensitivity in all three MMC-induced assays, whereas CHO and V79 showed varied sensitivity in different assays. In MN assay, the sensitivity of CHO is higher than or equal to V79; in SCE assay, the sensitivity of CHO is the same as V79; and in CA assay, the sensitivity of CHO is higher than V79. In-depth analysis of CA revealed that in chromatid breaks and dicentrics formation, lymphocyte was the most sensitive of all and CHO was more sensitive than V79; and in acentrics and interchanges formation, lymphocyte was much more sensitive than the others. Furthermore, we found caspase-3 activity plays an important role in MMC-induced cytogenetic assays, with MMC-induced caspase-3 activity resulting in more sensitivity in lymphocytes than in CHO and V79. Based on these findings, lymphocyte will make a suitable predictive or representative control reference in cytogenetic assays and caspase-3 activity with its high specificity, positive predictive value, and sensitivity.

Cardioprotective effects of luteolin during ischemia-reperfusion injury in rats.

BACKGROUND: Antioxidants effectively reduce ischemia-reperfusion (IR) injury. The cardioprotective effects of luteolin, a flavonoid that exhibits antioxidant properties and is widely available in many fruits and vegetables, were examined in rats subjected to myocardial IR injury. METHODS AND RESULTS: Rats were subjected to myocardial ischemia or reperfusion injury to evaluate the antiarrhythmic effects of luteolin. Myocardial infarct size was determined histochemically with triphenyltetrazolium chloride staining of the left ventricle. Luteolin was administered intravenously 15min before occlusion of the coronary artery. The incidence and duration of ventricular tachycardia and ventricular fibrillation and mortality during myocardial ischemia were significantly reduced by luteolin (10µg/kg). Similarly, luteolin (1µg/kg) reduced ventricular arrhythmias and mortality during the reperfusion phase. Pretreatment with luteolin decreased plasma lactate dehydrogenase and nitric oxide (NO) levels. Luteolin (10µg/kg) significantly reduced the myocardial infarct size, as well as malondialdehyde production in tissue samples of myocardial IR injury. Luteolin also downregulated inducible NO synthase protein and mRNA expression, but did not significantly alter neuronal NO synthase or endothelial NO synthase expression. CONCLUSIONS: Luteolin is capable of protecting the myocardium against IR injury. The actions of luteolin are at least partly mediated through downregulation of NO production and its own antioxidant properties.

Caffeic acid phenethyl ester ameliorates cerebral infarction in rats subjected to focal cerebral ischemia.

The effects of caffeic acid phenethyl ester (CAPE), an antioxidant derived from propolis, on the infarct volume elicited by focal cerebral ischemia were studied on Long-Evans rats. Cerebral infarction was induced by microsurgical procedures with ligation of the right middle cerebral artery (MCA) and clipping of bilateral common carotid arteries (CCA) for 60 min. The rats were sacrificed 24 h later and serial brain slices of 2 mm thickness were taken and stained for the measurement of infarct area. CAPE was administered intravenously 15 min before MCA occlusion. Pretreatment of CAPE (0.1, 1 and 10 microg/kg) significantly reduced the total infarct volume from 169.6 +/- 14.5 mm3 (control) to 61.0 +/- 24.1 mm3 (0.1 microg/kg CAPE), 47.4 +/- 9.1 mm3 (1 microg/kg CAPE), and 42.4 +/- 8.7 mm3 (10 microg/kg CAPE), respectively. Plasma nitric oxide (NO) content was significantly increased in rats subjected to focal cerebral ischemia. It is concluded that CAPE possesses neuroprotective properties in focal cerebral ischemia injury in rats possibly through its antioxidant effect and/or via the upregulation of NO production.

Antiarrhythmic effect of caffeic acid phenethyl ester (CAPE) on myocardial ischemia/reperfusion injury in rats.

OBJECTIVES: The present study was designed to determine the antiarrhythmic effect of caffeic acid phenethyl ester (CAPE), an active component of propolis, which exhibits antioxidant properties, in rats subjected to myocardial ischemia and ischemia-reperfusion (I/R) injury. DESIGN AND METHODS: Rats were subjected to 30 min coronary artery occlusion for evaluating the effect of CAPE on the myocardial ischemia injury. While in the myocardial I/R injury study, the coronary artery was ligated for a 5-min period of ischemia followed by a 30-min period of reperfusion. Animals were pretreated with or without CAPE before coronary artery ligation and the severity of myocardial ischemia- and I/R-induced arrhythmias and mortality were compared. RESULTS: Pretreatment of CAPE (0.1 and 1 microg/kg) not only reduced both the incidence and duration of ventricular tachycardia (VT) and ventricular fibrillation (VF) but also decreased the mortality during the myocardial ischemia and I/R injury period. CONCLUSIONS: Our results suggest that CAPE is a potent antiarrhythmic agent with cardioprotective effects in myocardial ischemia and I/R injury rats.