Effects of lipoxin A4 on human type II alveolar epithelial cell wound repair, proliferation and apoptosis

Abstract

Objective To evaluate the effects of lipoxin A4 (LXA4) on human type Ⅱ alveolar epithelial cell wound repair, proliferation and apoptosis. Methods Experiment Ⅰ Human type Ⅱ alveolar epithelial cells were inoculated in 24-well plates and divided into 4 groups (n=10 each) using a random number table: control group (group C), 1 nmol/L LXA4 group (group L1), 10 nmol/L LXA4 group (group L2) and 100 nmol/L LXA4 group (group L3). Cells were cultured in normal culture atmosphere in group C. Cells were incubated with 1, 10 and 100 nmol/L LXA4 in L1, L2 and L3 groups, respectively.The scratch wound assay was performed at 36 h of culture or incubation.Cell proliferation was measured at 24 h of culture or incubation.Experiment Ⅱ Human type Ⅱ alveolar epithelial cells were inoculated in 96-well plates and divided into 5 groups using a random number table: control group (group C, n=10), Fas-ligand group(n=10), Fas-ligand+ LXA4 group(n=10), Fas-ligand+ TNF-α group(n=5) and Fas-ligand+ TNF-α+ LXA4 group(n=5). Cells were incubated with 100 ng/ml Fas-Ligand, 100 ng/ml Fas-Ligand plus 100 nmol/L LXA4, 100 ng/ml Fas-Ligand plus 100 ng/ml TNF-α, and 100 ng/ml Fas-Ligand plus 100 ng/ml TNF-α plus 100 nmol/L LXA4 in Fas-ligand, Fas-ligand+ LXA4, Fas-ligand+ TNF-α, and Fas-ligand+ TNF-α+ LXA4 groups, respectively.The cell viability was measured at 24 h of culture or incubation.Cell apoptosis was detected using the flow cytometry, and apoptosis rate was calculated in C, Fas-ligand and Fas-ligand+ LXA4 groups. Results Experiment Ⅰ Compared with group C, the percentage of cell repair size and percentage of proliferation were significantly increased in L1, L2 and L3 groups (P 0.05). Experiment Ⅱ Compared with group C, the cell viability was significantly decreased, and the apoptosis rate was increased in group Fas-ligand, the cell viability was significantly decreased in group Fas-ligand+ TNF-α (P 0.05). Compared with group Fas-ligand, the cell viability was significantly increased, and the apoptosis rate was decreased in group Fas-ligand+ LXA4 (P<0.05). The cell viability was significantly higher in group Fas-ligand+ TNF-α+ LXA4 than in group Fas-ligand+ TNF-α (P<0.01). Conclusion LXA4 can promote human type Ⅱ alveolar epithelial cell wound repair and proliferation and inhibit the apoptosis. Key words: Lipoxins; Pulmonary alveoli; Epithelial cells; Cell proliferation; Apoptosis; Recovery of function