Abstract:

Objective   To investigate the effects of the unfolded protein response(UPR) in endoplasmic reticulum stress on the apoptosis of rat pulmonary microvascular endothelial cells(rPMECs) induced by lymph from rats with severe scalds. Methods   Twenty Wistar rats were divided into burn group(n=10) and sham burn group(n=10). Lymph was harvested within 24 hours after the establishment of scalds model. Cultured rPMECs were divided into scald lymph stimulated group (A，stimulated by 5% scalded rat lymph), scald lymph and 4-PBA group (B, stimulated by 5% scalded rat lymph and 5mM 4-PBA) and control group(C，5% sham scalded rats lymph). Cells apoptosis was determined by flow cytometery with annexin V/PI. Expressions of protein of GRP78, CHOP and Caspase 12 were determined by western blotting.  Results   Significant apoptotic cells were determined in group A, which was higher than that of group C(P<0.01). There was significant decrease of apoptosis of cell treated with 4-PBA and burn lymph. Protein level of GRP78, CHOP and Caspase12 increased significantly when treated with burn lymph, but decreased when treated by 4-PBA(P<0.01). Conclusion   Lymph from rats with severe scalds can induce significant apoptosis in rPMECs. UPR may be the main pathway of apoptosis, which can be improved by 4-PBA.

Key words: Lymph; Endothelial cell; Unfolded protein response; Apoptosis; Lung injury