Figure 5
Cardiac contractility measurements in vivo and ex vivo: Cardiac contractility was measured by ECG and Langendorff after 5 weeks of scaffold implantation. Scaffold was implanted following a myocardial infarction. Electrocardiograms were recorded in conscious rats by non-invasive methods to avoid effect of anesthesia. (A) ECG measurements were performed after 5 weeks of MI. Coronary artery ligation significantly increased QRS interval. The implantation of only chitosan (MI + CS group) was not able to improve QRS duration, however conductive polymer scaffold (MI + scaffold group) implantation significantly improved the QRS intervals in MI induced hearts. (B) Histograms showing QRS interval duration. (C,D) At the end of in vivo experiments, the animals were anaesthetized and the hearts were removed and perfused on a Langendorff apparatus. The minimum and maximum rate of pressure rise dp/dt min and dp/dt max (two sensitive indices for contractility) were calculated. Both dp/dt min and dp/dt max decreased in MI groups, The implantation of only chitosan was not able to increase dp/dt min and dp/dt max, however conductive polymer scaffold implantation led to a significant increase in dP/dt min (C) and dP/dt max (D). *P < 0.05 compared to sham group, #P < 0.05 compared to MI group, $P < 0.05 compared to MI + CS group. (n = 5) Data are expressed as mean ± SD.
