Protective effects of tetrahydropalmatine against gamma-radiation induced damage to human endothelial cells.
OBJECTIVE
Irradiation-induced damage to pulmonary endothelial cells is thought to be an important mediator of the pathogenesis of radiation pneumonopathy. Tetrahydropalmatine (THP) has been shown to have a protective effect against oxidative stress. This study was designed to investigate the potential radioprotective effect of THP against irradiation-induced endothelial cellular damage and to elucidate the underlying mechanisms.


METHODS
Human EA.hy926 cells were treated with THP and irradiation. Cell viability was measured using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. For the detection of apoptosis, morphological observation, flow cytometry and a caspase-3 activity assay were employed. The expression of cytochrome-c and Bax/Bcl-2 protein were detected by western blot analysis. Generation of reactive oxygen species (ROS) was measured by flow cytometry. Malondialdehyde (MDA), lactate dehydrogenase (LDH), glutathione (GSH) and superoxide dismutase (SOD) were measured to assess cellular oxidative stress induced injury.


RESULTS
Preincubation of EA.hy926 cells with THP before gamma-radiation resulted in significant inhibition of apoptosis and enhancement of cell viability, as revealed by morphological observation, flow cytometry and MTT assay. THP significantly reduced intracellular ROS formation, levels of intracellular MDA and LDH, and enhanced the production of intracellular antioxidants (GSH and SOD) in EA.hy926 cells. Meanwhile, THP also inhibited the decrease of intracellular mitochondrial membrane potential (psim), caspase-3 activation, cytochrome-c release and reduced Bax/Bcl-2 ratio in THP pretreated, irradiated cells.


CONCLUSIONS
Our findings demonstrated THP could effectively protect endothelial cells against gamma-irradiation injury, which could potentially be applied to the prevention of endothelial cell dysfunctions associated with ionizing irradiation-induced lung injury.
Yu
Jing
J
Department of Oncology, Guang 'anmen Hospital, China Academy of Chinese Medical Sciences, 5 Beixiange Road, Xuanwu District, Beijing, PR China.
Piao
Bin-kui
BK
Pei
Ying-xia
YX
Qi
Xin
X
Hua
Bao-jin
BJ
D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D001600:Berberine Alkaloids / Q000494:pharmacology*; D053148:Caspase 3 / Q000187:drug effects / Q000528:radiation effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D045304:Cytochromes c / Q000187:drug effects / Q000528:radiation effects; D042783:Endothelial Cells / Q000187:drug effects / Q000528:radiation effects; D005434:Flow Cytometry; D005720:Gamma Rays / Q000009:adverse effects*; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000528:radiation effects; D018384:Oxidative Stress / Q000187:drug effects* / Q000528:radiation effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011832:Radiation Injuries / Q000517:prevention & control*; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000528:radiation effects; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D001600:Berberine Alkaloids; D019253:Proto-Oncogene Proteins c-bcl-2; D011837:Radiation-Protective Agents; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; C014215:tetrahydropalmatine; D045304:Cytochromes c; D053148:Caspase 3