Mp150 multipurpose polygraph

At 24 h after last administration, rats were weighed by Ohaus AR3130 electronic balance (Pinebrook, NJ, USA) and anesthetized by intraperitoneal injection of 20% ethyl carbamate (1.5 g/kg). A venous cannula was inserted into the left ventricular cavity of rat through the right common carotid artery. Then, heart rate (HR), left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), maximal rate of the increase of left ventricular pressure (+dp/dt_max), maximal rate of the decrease of left ventricular pressure (−dp/dt_max) were recorded with the aid of Biopac MP150 multipurpose polygraph (Goleta, CA, USA). The mean of 5 segments recorded value of above-described hemodynamic indices was used for statistical analysis.

Before operation, the electrocardiography of each rat was monitored by Biopac MP150 multipurpose polygraph (Goleta, CA, USA). Rats with normal electrocardiography were used to establish CHF model by coronary artery ligation according to previous procedure (Li et al., 2011 (link)). Briefly, after rats were anesthetized by intraperitoneal injection of 20% ethyl carbamate (1.5 g/kg), coronary artery ligation was achieved with a gab occluder fixed onto the left anterior descending coronary artery. A 6-0 silk suture was passed underneath the left anterior descending (1–2 mm inferior to the left auricle) and tied. The electrocardiography of rat was instantly monitored. If the electrocardiography ST segment elevation was observed, the coronary artery ligation was successfully performed. Then, the chest was closed in layers, and the respirator weaned when the rat recovered spontaneous breathing. Subsequently, rats were subcutaneously injected with normal saline (30 mL/kg) to replenishing fluid loss and were locally treated with povidone-iodine and benzylpenicillin sodium to disinfection and anti-infection. Sham-operated rats underwent all the above-described surgical procedures, except that the 6-0 silk suture, passing around the left anterior descending, was not tied.