The Experiment Study Of Paraquat Induced Apoptosis Of Rat Pulmonary Microvascular Endothelial Cells

BACKGROUND AND OBJECTIVE: Paraquat (PQ) is widely used as a universal herbicide and the frequent toxicity that causes human death. PQ causes lung injury by enhancing oxidative stress. Oxidative stress may be the common final passageway that many stimulants cause apoptosis. It is well known that PQ can generate O₂ radicals and injure pulmonary microvascular endothelial cells (PMVECs) in vivo and in vitro. However, whether PQ-induces apoptosis of PMVECs and the mechanisms by which PQ causes acute lung injure is not known. Recent studies have shown that PQ can induce apoptosis of some cells. In the present study, we examined the direct toxic and apoptotic effects of PQ on cultured rat PMVECs, in order to study the mechanisms of PQ intoxication.METHODS: Primary cultures of male Sprague-Dawley rat PMVECs were identified. Cultured rat PMVECs were incubated with different concentrations of PQ and different time periods. The toxic and apoptotic effects were studied by MTT method, DNA fragmentation (agarose gel electrophoresis), nucleic morphology (DAPI staining), and flow cytometry .RESULTS: Rat PMVECs were cultured successfully. It was found with MTT method that PQ inhibited the proliferation and metabolism of rat PMVECs in vitro in a dose- and time-dependent manner. Apoptotic DNA ladder were demonstrated by agarose gel electrophoresis. Apoptotic features such as chromatin condensation and nuclei fragmentation were shown by the morphological of the nuclei. Flow cytometry revealed subG_0/1 peaks (PI staining).CONCLUSIONS: PQ could inhibite the proliferative activity and induce apoptosis of rat PMVECs in vitro. Apoptosis of rat PMVECs may be one of the mechanisms of PQ induced acute lung injury (ALI).