Inhibition of the cystathionine-gamma-lyase/hydrogen sulfide pathway in rat vascular smooth muscle cells by cobalt-60 gamma radiation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Radiation is a promising treatment for in stent restenosis and restenosis following percutaneous transluminal coronary angioplasty, which has troubled interventional cardiologists for a long time. It inhibits neointima hyperplasia, vascular remodeling, and increases the mean luminal diameter. The mechanism of intracoronary brachytherapy for restenosis is not well understood. Endogenous gaseous transmitters including nitric oxide and carbon monoxide are closely related to restenosis. Hydrogen sulfide, a new endogenous gaseous transmitter, is able to inhibit the proliferation of vascular smooth muscle cells and vascular remodeling. This study aimed to clarify the effect of radiation on cystathionine-gamma-lyase/hydrogen sulfide pathway in rat smooth muscle cells.</p><p><b>METHODS</b>We studied the effect of radiation on the cystathionine-gamma-lyase/hydrogen sulfide pathway. Rat vascular smooth muscle cells were radiated with (60)Co gamma at doses of 14 Gy and 25 Gy respectively. Then the mRNA level of cystathionine-gamma-lyase was studied by quantitative reverse-transcription competitive polymerase chain reaction. Hydrogen sulfide concentration in culture medium was determined by methylene blue spectrophotometry. Cystathionine-gamma-lyase activity in vascular smooth muscle cells was also studied.</p><p><b>RESULTS</b>(60)Co gamma radiation at a dose of 1 Gy did not affect the cystathionine-gamma-lyase/hydrogen sulfide pathway significantly. However, (60)Co gamma radiation at doses of 14 Gy and 25 Gy decreased the hydrogen sulfide synthesis by 21.9% (P<0.05) and 26.8% (P<0.01) respectively. At the same time, they decreased the cystathionine-gamma-lyase activity by 15.1% (P<0.05) and 20.5% (P<0.01) respectively, and cystathionine-gamma-lyase mRNA expression by 29.3% (P<0.01) and 38.2% (P<0.01) respectively.</p><p><b>CONCLUSION</b>Appropriate (60)Co gamma radiation inhibits the H(2)S synthesis by inhibiting the gene expression of cystathionine-gamma-lyase and the cystathionine-gamma-lyase activity.</p>

Effects of hydrogen sulfide on the K ATP current in isolated rat ventricular myocytes / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of endogenous and exogenous hydrogen sulfide (H(2)S) on the K(ATP) current in isolated rat ventricular myocytes.</p><p><b>METHODS</b>Ventricular myocytes were isolated from rat heart by modified Langendorff perfusion with collagenase. K(ATP) current of single rat ventricular myocytes was recorded by whole-cell patch-clamp technique.</p><p><b>RESULTS</b>The density of K(ATP) current was significantly reduced by 200 micromol/L DL-propargylglycine (PPG, an irreversible inhibitor of the H(2)S) [(5.3258 +/- 0.7556) pA/pF vs. (3.7856 +/- 0.4312) pA/pF, P < 0.01] in a time-dependent way. The density of K(ATP) current could be significantly increased by NaHS (a H(2)S donor, 9.375, 18.75, 37.5, 75, 150 micromol/L) in a concentration-dependent manner [(6.6310 +/- 0.6092) pA/pF vs. (9.0949 +/- 1.0259) pA/pF at 150 micromol/L, P < 0.01].</p><p><b>CONCLUSION</b>Both endogenous and exogenous H(2)S could open K(ATP) channels and enhance the K(ATP) current in rat ventricular myocytes.</p>