Effects of different densities of rat cardiac fibroblasts subjected to hypothermic hypoxia-reoxygenation on cardiomyocyte injury / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effects of different densities of rat cardiac fibroblasts (RCF) subjected to hypothermic hypoxia-reoxygenation on cardiomyocyte injury and intercellular coupling.Methods:RCF was cultured in vitro and divided into 3 groups ( n=12 each) using a random number table method: RCF density 0.5×10 5 cells/ml group (T 0.5 group), RCF density 1.0×10 5 cells/ml group (T 1.0 group), and RCF density 2.0×10 5 cells/ml group (T 2.0 group). The three groups were placed in an anoxic device, into which 95% N 2 + 5% CO 2 was continuously blown at the speed of 5 L/min for 15 min, and then placed in a 4 ℃ refrigerator for 1 h for low temperature treatment.After completion of culture, cells were placed in a incubator containing 95% air + 5% CO 2 at 37 ℃ for 4 h of reoxygenation.After the end of culture, RCF in three groups were indirectly co-cultured with cardiomyocytes of the same density (1.0×10 5 cells/ml) in a Transwell chamber for 16 h, cardiomyocytes were seeded in the lower chamber of Transwell, and RCF were seeded in the upper chamber of Transwell.After the end of co-culture, cardiomyocytes were collected for determination of the cell viability (by CCK8 method), apoptosis rate (by flow cytometry), expression of connexin 43 (Cx43) mRNA (by real-time fluorescence quantitative polymerase chain reaction), and expression of Cx43 and phosphorylated Cx43 (p-Cx43) (by Western blot). Results:Compared with T 0.5 group, the cell viability, apoptosis rate and expression of Cx43, p-Cx43 and Cx43 mRNA were significantly decreased in T 1.0 and T 2.0 groups ( P<0.01). Compared with T 1.0 group, the cell viability, apoptosis rate and expression of Cx43 and p-Cx43 were significantly decreased ( P<0.01), and no significant change was found in expression of Cx43 mRNA in cardiomyocytes in T 2.0 group ( P>0.05). Conclusions:RCF subjected to hypothermic hypoxia-reoxygenation induces cardiomyocyte injury in a density-dependent manner in a certain range, and the mechanism may be related to down-regulation of the expression of Cx43 and reduction of the activity of Cx43.