Apoptosis of vascular smooth muscle cells induced by photodynamic therapy with protoporphyrin IX.
Photodynamic therapy (PDT) had been shown effective in the treatment of intimal hyperplasia, which contributes to restenosis, by eradicating cells in the vessel wall. This study is designed to evaluate the effects of PDT with protoporphyrin IX (PpIX) on the viability of vascular smooth muscle cells (SMCs) and to define the cell-death pathway. Fluorescence microscopy and laser-induced fluorescence spectroscopic detection showed that SMCs selectively uptake PpIX, and the intracellular PpIX concentration increases with the amount of PpIX in the incubation solution. PDT with PpIX impaired cellular viability from 93+/-3.4% to 36+/-3.9% when the light intensity increases from 2 to 9J/cm(2) and intracellular PpIX concentration increases from 0.5 to 20 microg/ml. Although PDT induced both apoptosis and necrosis, the ratio of apoptotic cells increased with light dosage or intracellular PpIX concentration. The loss of mitochondrial membrane potential coincided with the apoptotic ratio. Our results indicated that the induction of apoptosis of SMCs may be one of the mechanisms by which PDT inhibits restenosis in vivo.
Li
Qingsong
Q
Department of Cardiology, The Second Affiliated Hospital, Harbin Medical University, Harbin 150081, PR China.
Cheng
Jiali
J
Peng
Chenghai
C
Li
Zhitao
Z
Shi
Sa
S
Liang
Huijuan
H
Tian
Ye
Y
Zhang
Zhiguo
Z
Cao
Wenwu
W
D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D023903:Coronary Restenosis / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D006965:Hyperplasia; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008856:Microscopy, Fluorescence; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D010778:Photochemotherapy; D011524:Protoporphyrins / Q000378:metabolism* / Q000627:therapeutic use; D017539:Tunica Intima / Q000187:drug effects / Q000378:metabolism / Q000473:pathology
D011524:Protoporphyrins; C028025:protoporphyrin IX