Tropisetron inhibits sepsis by repressing hyper-inflammation and regulating the cardiac action potential in rat models.

OBJECTIVE: The objective of the present investigation was to explore the possible effect of the 5-HT3 receptor antagonist tropisetron on the expression levels of the inflammatory factors interleukin 6 (IL-6), creatine kinase isoenzyme (CK-MB), soluble growth stimulating gene 2 protein (sST2) and immunoglobulin E (IgE), as well as the cardiac action potential in septic rats.

METHODS: The cecal ligation and perforation (CLP) method was utilized to construct abdominal infarction in rats. A total of 68 male adult Sprague Dawley rats were used, including 40 for assessing survival and 28 for detecting the expression levels of IL-6 and IgE, myocardial injury, cardiac dysfunction and the cardiac action potential. These 28 rats were divided into the sham (6 rats), sham + Tropisetron (6 rats), CLP (8 rats) and CLP + Tropisetron (8 rats) groups. Twenty-four hours after establishment of the sepsis rat model, immunohistochemistry was used to analyze 5-HT3 receptor protein expression, and enzyme-linked immunosorbent assay (ELISA) was employed to monitor the serum levels of IL-6, CKMB, sST2 and IgE. Furthermore, the structure of the myocardium in various groups was examined by H&E staining.

RESULTS: The levels of IL-6, CK-MB, sST2 and IgE in the sepsis group were significantly higher than those of the sham group (P <  0.01). Furthermore, the heart rate in the sepsis group was lower than that of the sham group (P <  0.01), and the time of atrial ventricular action potential in the sepsis group was longer than that of the sham group (P <  0.05). In addition, immunohistochemical analyses showed that the area, intensity and index of 5-HT3 receptor in the sepsis group were significantly lower than those of the sham group (P <  0.01). Importantly, the 5-HT3 receptor antagonist Tropisetron exhibited significant inhibitory effects IL-6, CK-MB, sST2 and IgE expression levels, and inductive effects on atrial ventricular action potential in the sepsis group.

CONCLUSIONS: Sepsis leads to systemic inflammatory reaction, resulting in myocardial injury, structural changes and immune imbalance. The inhibitory effect of tropisetron on inflammation, and the regulatory inflammatory disorder by the efferent vagus nerve may be one of the important mechanisms leading to cardiac electrophysiological changes in sepsis.