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Quercetin-filled phosphatidylcholine liposomes restore abnormalities in rat thoracic aorta BKCa channel function following ionizing irradiation

SOLOVIEV Anatoly^*, TISHKIN Sergey, KYRYCHENKO Sergey

Institute of Pharmacology and Toxicology, Academy of Medical Science, Kiev 03057, Ukraine

Abstract

The goal of the present study was to investigate the effects of quercetin-filled phosphatidylcholine liposomes (PCL-Q) on the currents carried by large conductance Ca2+-dependent K+ channels (BKCa) in rat thoracic aorta following non-fatal whole-body ionizing irradiation. Using patch-clamp technique, it is found that the outward K+ currents of isolated smooth muscle cells (SMCs) stimulated by depolarizing voltage steps were sensitive to BKCa inhibitor, paxilline, and this kind of outward K+ currents in SMCs from irradiated animals demonstrated a significant decrease in amplitude. Radiation-induced BKCa suppression was evident 9 days postirradiation and progressively increased over 30 days of experimental period. Thus, the vasorelaxing force of these SMCs may be diminished following irradiation. PCL-Q effectively restored BKCa function in post-irradiated SMCs. It is noteworthy that the constituents of PCL-Q, i.e., free quercetin (Q) and “empty” liposomes (PCL), being taken separately, showed a decreased ability to recover BKCa function as compared with combined composition. These results suggest that PCL-Q is able to regain normal function of BKCa following irradiation. The protective effects of PCL-Q can be explained by its antioxidant and membrane repairing properties as well as its ability to inhibit protein kinase C activity. Thus, the lipid encapsulation of flavonoid, PCL-Q, appears to be a potential medication in the case of ionizing irradiation accident, and for the patients with neoplasm who have to receive external radiotherapy as well.

Key words: smooth muscle; radiation; reactive oxygen species; potassium channels; quercetin; liposomes; protein kinase C

Received: 2008-12-31　　Accepted: 2009-04-15

Corresponding author: SOLOVIEV Anatoly　　E-mail: tonysolpharm@ukrpost.ua

Citing This Article：

SOLOVIEV Anatoly, TISHKIN Sergey, KYRYCHENKO Sergey. Quercetin-filled phosphatidylcholine liposomes restore abnormalities in rat thoracic aorta BKCa channel function following ionizing irradiation. Acta Physiol Sin 2009; 61 (3): 201-210 (in Chinese with English abstract).