RESUMO
Objective:To evaluate the role of autophagy in reduction of high glucose and hypoxia-reoxygenation (HG+ H/R) injury to isolated cardiomyocytes by dexmedetomidine in rats.Methods:The normally cultured rat H9c2 cardiomyocytes at the logarithmic growth phase were seeded in 6-well plates at a density of 1×10 6 cells/ml and divided into 4 groups ( n=15 each) using a random number table method: control group (group C), group HG+ H/R, dexmedetomidine group (group DEX) and dexmedetomidine+ autophagy inhibitor 3-methylpurine group (group 3-MA). The cells were incubated in culture medium with 1% fetal bovine serum + 1% double antibody for 24 h when the cell density reached 50%.To establish HG+ H/R injury model, the cardiomyocytes were cultured in high-glucose culture medium (glucose concentration of 33 mmol/L) for 24 h, and then incubated in a 37 ℃ incubator (95% N 2+ 5%CO 2) for 4 h followed by reoxygenation (90%O 2+ 10%CO 2) for 2 h. Dexmedetomidine was added until the final concentration reached 5 μmol/L at 1 h before hypoxia in DEX and 3-MA groups, and 3-MA was added until the final concentration reached 5 μmol/L at 1 h of incubation with dexmedetomidine.At 2 h after reoxygenation, the cell viability was recorded by the cell counting kit-8 assay, lactate dehydrogenase (LDH) activity was detected by LDH kit, the expression of autophagy-related protein LC3, P62 and Beclin-1 was detected by Western Blot, the ratio of LC3Ⅱ/LC3Ⅰwas calculated, and the expression of P62 and Beclin-1 mRNA was detected by real-time polymerase chain reaction. Results:Compared with group C, the cell viability was significantly decreased in HG+ H/R, DEX and 3-MA groups, LDH activity in the supernatant was increased and expression of P62 was decreased in HG+ H/R and 3-MA groups, ratio of LC3Ⅱ/LC3Ⅰwas decreased in group 3-MA, and the expression of Beclin-1 was down-regulated in group HG+ H/R ( P<0.05). Compared with HG+ H/R group, LDH activity in the supernatant was significantly decreased, expression of Beclin-1, P62 and its mRNA was up-regulated, and ratio of LC3Ⅱ/LC3Ⅰwas increased in DEX group, and LDH activity in the supernatant was increased in group 3-MA ( P<0.05). Compared with DEX group, cell viability were decreased, LDH activity in the supernatant was increased, Beclin-1, P62 and its mRNA was down-regulated, and ratio of LC3Ⅱ/ LC3Ⅰwas decreased in group 3-MA ( P<0.05). Conclusion:Autophagy is involved in the reduction of HG+ H/R injury to isolated cardiomyocytes by dexmedetomidine in rats.
RESUMO
Bacterial cell division is strictly regulated in the formation of equal daughter cells. This process is governed by a series of spatial and temporal regulators, and several new factors of interest to the field have recently been identified. Here, we report the requirement of gluconate 5-dehydrogenase (Ga5DH) in cell division of the zoonotic pathogen Streptococcus suis. Ga5DH catalyzes the reversible reduction of 5-ketogluconate to D-gluconate and was localized to the site of cell division. The deletion of Ga5DH in S. suis resulted in a plump morphology with aberrant septa joining the progeny. A significant increase was also observed in cell length. These defects were determined to be the consequence of Ga5DH deprivation in S. suis causing FtsZ delocalization. In addition, the interaction of FtsZ with Ga5DH in vitro was confirmed by protein interaction assays. These results indicate that Ga5DH may function to prevent the formation of ectopic Z rings during S. suis cell division.