Acute effects of granulocyte colony-stimulating factor on early ventricular arrhythmias after coronary occlusion in rats

Abstract

Objectives: To evaluate the acute effects of colony-stimulating factor (G-CSF) on ventricular arrhythmias after coronary occlusion in rats.

Materials and methods: Male Wistar rats (10 weeks) received G-CSF (100 μg.kg(-1)) or vehicle. Thirty minutes later, animals were infarcted by coronary occlusion under artificial respiration. Electrocardiogram was monitored for 30 min to evaluate ventricular arrhythmias.

Results: G-CSF treatment reduced the number of premature ventricular beats and the number and duration of ventricular tachycardia. The incidence of ventricular fibrillation was significantly reduced by G-CSF (MI-Cont: 11.2 ± 2.4 vs. MI-GCSF: 5.4 ± 1 events; P < 0.05). However, total duration of ventricular fibrillation was not altered (MI-Cont: 84 ± 16 vs. MI-GCSF: 76 ± 13 sec).

Conclusions: Acute administration of G-CSF before coronary ligature in rats reduces the incidence of ventricular premature beats and ventricular tachycardia, suggesting a possible direct electrophysiological effect of this cytokine independently of its genomic effects. However, the data suggest that G-CSF treatment may affect the spontaneous recovery from ventricular fibrillation. Acute G-CSF administration acts directly on cardiac electrophysiology, different from chronic treatment.

Keywords: Arrhythmias; G-colony-stimulating factor; myocardial infarction.

Figure 1

Temporal distribution of ventricular premature beats after coronary occlusion (nine animals for each group). The comparison was performed using the area under curve (AUC) (upper panel). ^* P < 0.05

Figure 2

Events of ventricular tachycardia in the first 30 minutes following coronary occlusion (nine animals per group). Area under curve (AUC) was used to compare temporal distribution of the events (upper panel). ^* P < 0.05