RESUMEN
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.
RESUMEN
Objective:To evaluate the effects of different density rat fibroblasts on the expression of conjunctin 43 (Cx43) in cardiomyocytes and cell viability.Methods:Cardiomyocytes and fibroblasts were co-cultured using Transwell, cardiomyocytes were inoculated into the lower chamber of Transwell and fibroblasts into the upper chamber of Transwell.The cells were divided into 3 groups ( n=12 each) by a random number table method: fibroblast density 0.5×10 5 cells/ml group (group C 0.5), fibroblast density 1×10 5 cells/ml group (group C 1), and fibroblast density 2×10 5 cells/ml group (group C 2), with the density of cardiomyocytes 1×10 5 cells/ml in three groups.Cardiomyocytes and fibroblasts were co-cultured for 20 h in three groups.Cardiomyocytes were collected after co-culture for determination of cell viability (by CCK8 method), apoptosis rate (by flow cytometry), and expression of Cx43 mRNA (by quantitative real-time polymerase chain reaction) and expression of Cx43 and phosphorylated Cx43 (p-Cx43) (by Western blot). Results:There was no significant difference in the apoptosis rate of cardiomyocytes among the three groups ( P>0.05). Compared with group C 0.5, the expression of Cx43 protein and mRNA and p-Cx43 was significantly up-regulated in group C 1, the cardiomyocyte viability was significantly increased, and the expression of Cx43 protein and mRNA and p-Cx43 was up-regulated in group C 2 ( P<0.05). Compared with group C 1, the cardiomyocyte viability was significantly increased, and the expression of Cx43 protein and mRNA and p-Cx43 was up-regulated in group C 2 ( P<0.05). Conclusion:Rat fibroblasts up-regulate the expression of Cx43 and enhance the activity of Cx43 in cardiomyocytes and enhance cell viability in a density-dependent manner in a certain range.
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Objective:To probe the mechanism of inhibition in gap junction-mediated intercellular communication (GJIC) of rabbit lens epithelia cells(RLECs) irradiated by UVA. Methods:RLECs of 2～3 generation were divided into normal control group and ultraviolet irradiation group (The UV intensity was 0.2 mW/cm2 under a UV lamp with fixed position 50 cm, RLECs were exposed to ultraviolet lamp at different times: 5,10,15 minutes). Western blot techniques were employed to detect the protein levels of Cx43 irradiated by UVA. By indirect immunofluorescence histochemistry we analyzed the localization of Cx43 in the RLECs. Results:In UVA irradiation group and normal control group,there was expression of Cx43. With the increasing intensity,the expression of Cx43 was decreasing. The immunnostaining of Cx43 in RLECs revealed that the internalization of Cx43 from membrance to plasma and nuclear was found in UVA irradiated RLECs. Conclusion: Cell molecule level study proved UVA irradiation can reduce GJIC of RLECs,which wis associated with perturbations in localization and number of Cx43 among RLECs.