ABSTRACT
Objective To evaluate the relationship between the expression of Nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) in nerve tissues and mitochondrial function during mechanical stretch-induced damage to mouse alveolar epithelial cells.Methods Alveolar epithelial type Ⅱ cell line MLE-12 cells were divided into 3 groups (n=13 each) using a random number table:control group (group C),cyclic stretch group (group CS) and cyclic stretch plus NLRP3 inhibitor TAK-242 group (group CS+T).MLE-12 cells underwent 20％ cyclic stretch at a frequency of 0.5 Hz (stretch ∶ intermittence =1 ∶ 1) for 4 h in group CS.In group CS+T,after being incubated for 1 h with 1 μ mol/L TAK-242,MLE-12 cells underwent 20％ cyclic stretch for 4 h,and the parameters were similar to those previously described in group CS.The reactive oxygen species (ROS) content and mitochondrial membrane potential (△ΨM) were measured using chemiluminescence assay.Enzyme-linked immunosorbent assay was used to determine the concentration of interleukin-1 beta (IL-1β) in the supernatant.The expression of NLRP3 in MLE-12 cells was detected using Western blot.Results Compared with group C,the △ΨM of cells was significantly decreased,the ROS content and IL-1β concentration were increased,and the expression of NLRP3 was up-regulated in group CS,and the △ΨM of cells was significantly decreased,the ROS content was increased,and the expression of NLRP3 was up-regulated in group CS+T (P＜0.05).Compared with group CS,the △ΨM of cells was significantly increased,the ROS content and IL-1β concentration were decreased,and the expression of NLRP3 was down-regulated in group CS+T (P＜ 0.05).Conclusion Mechanical stretch induces damage to mitochondria through up-regulating the expression of NLRP3,thus leading to damage to mouse alveolar epithelial cells.
ABSTRACT
Objective To evaluate the effect of recombinant human annexin A5 on the expression of phosphorylated protein kinase C alpha (p-PKCα) and p120-catenin during endotoxin-induced damage to cardiomyocytes.Methods H9c2 cells cultured in vitro were randomly divided into 3 groups (n=18 each) using a random number table:control group (group C),endotoxin group (group L),and recombinant human annexin A5 group (group A).Recombinant human annexin A5 (final concentration 5 ng/ml) was added,and the cells were incubated for 2 h in group A,and then lipopolysaccharide (final concentration 1 μg/ml) was added,and the cells were incubated for 4 h in L and A groups.At 4 h of incubation,cell apoptosis was detected using the cell apoptosis detection kit,the intercellular space was measured using the confocal microscopy,and the expression of p-PKCα and p120-catenin was determined by Western blot.The apoptosis rate was calculated.Results Compared with group C,the apoptosis rate was significantly increased,the intercellular space was significantly widened,the expression of p120-catenin was significantly down-regulated,and the expression of p-PKCα was significantly up-regulated in group L (P＜0.05).Compared with group L,the apoptosis rate and intercellular space were significantly decreased,the expression of p120-catenin was significantly up-regulated,and the expression of p-PKCα was significantly down-regulated in group A (P＜0.05).Conclusion Recombinant human annexin A5 can inhibit phosphorylation of PKCα and up-regulate the expression of p120-catenin,thus attenuating endotoxin-induced damage to cardiomyocytes.