Role of HO-1-induced endogenous protection in LPS-caused apoptosis in rat alveolar macrophages: relationship with endoplasmic reticulum stress / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of heme oxygenase-1 (HO-1)-induced endogenous protection in lipopolysaccharide (LPS)-caused apoptosis in rat alveolar macrophages and the relationship with endoplasmic reticulum stress.Methods:Alveolar macrophages of rats were randomized into 4 groups ( n=32 each) using a random number table method: control group (group C), LPS group (group L), Con siRNA group and HO-1 siRNA group. Cells were cultured normally in group C, and 10 μg/ml LPS was added to the culture medium in the other three groups. Con siRNA and HO-1 siRNA transfection was performed at 48 h before adding LPS in Con siRNA and HO-1 siRNA groups. At 24 h of treatment with LPS, MTT method was used to measure the cell viability, flow cytometry was used to determine the cell apoptosis rate, and Western blot was used to detect the expression of glucose regulatory protein 78 (GRP78), phosphorylated kinase receptor-like endoplasmic reticulum kinase (p-PERK), CCAAT/enhancer-binding protein homologous protein (CHOP), phosphorylated type I endoplasmic reticulum transmembrane protein kinase (p-IRE-1), phosphorylated stress-activated protein kinase (p-JNK) and caspase-12. Results:Compared with group C, the cell viability was significantly decreased, cell apoptosis rate was increased, and the expression of HO-1, GRP78, CHOP, p-PERK, p-IRE-1, p-JNK and caspase-12 was up-regulated in the other three groups ( P<0.05). Compared with group L, the cell viability was significantly decreased, cell apoptosis rate was increased, and the expression of HO-1 was down-regulated, and the expression of GRP78, CHOP, p-PERK, p-IRE-1, p-JNK and caspase-12 was up-regulated in group HO-1 siRNA ( P<0.05), and no significant change was found in each parameter in group Con siRNA ( P>0.05). Compared with group Con siRNA, the cell viability was significantly decreased, cell apoptosis rate was increased, and the expression of HO-1 was down-regulated, and the expression of GRP78, CHOP, p-PERK, p-IRE-1, p-JNK and caspase-12 was up-regulated in group HO-1 siRNA ( P<0.05). Conclusion:The mechanism of HO-1-induced endogenous protection is related to inhibiting endoplasmic reticulum stress and then reducing LPS-induced apoptosis in alveolar macrophages of rats.