Effects of MAPKs signaling on heat stress-induced apoptosis of pulmonary microvascular endothelial cells and its mechanism

Objective To investigate the effect of mitogen-activated protein kinases (MAPKs) activation on the heat stress- induced apoptosis of pulmonary microvascular endothelial cells (PMVECs). Methods A mouse model of severe heat stroke was made and TUNEL and immunohistochemistry were employed to detect lung tissue damage. MACS separation was used for isolation of neonatal PMVECs, and TUNEL was utilized to detect the apoptosis of PMVECs. Western blotting was used for determining the MAPKs activation during heat stress recovery (0, 2, 6h). The monolayer permeability of endothelial cells was detected in terms of transmembrane resistance (TEER) and horseradish peroxidase (HRP). Cells were pretreated with MAPKs activation inhibitors to examine the effect of heat stress on the monolayer cell permeability and apoptosis. Results In mice with severe heat stroke, extensive apoptosis of PMVECs was found in their pulmonary tissues. TUNEL revealed that the number of apoptotic cells increased over time during heat stress recovery period and heat stress could activate MAPKs in PMVECs. Compared with heat stress group, in the cells pretreated with p38 or ERK activation inhibitor PD98059 and SB203580, the monolayer permeability and apoptosis increased while in cells pretreated with JNK inhibitor SP600125, the cellular permeability and apoptosis decreased. Conclusion In mice with severe heat stoke, PMVECs might experience apoptosis and p38 and ERK could inhibit apoptosis while JNK could promote apoptosis. DOI: 10.11855/j.issn.0577-7402.2017.04.02