OBJECTIVEHydrogen sulfide, a well known toxic gas, has been found to play important roles in many organs and tissues, especially in cardiovascular system recently. The aim of this study was to explore the producing rate of hydrogen sulfide (H(2)S) in aorta and the level of H(2)S in plasma of spontaneous hypertensive rats (SHR), and to study the role of H(2)S on the development of hypertension.

METHODSTwenty-four male SHR rats at the age of 4 weeks were randomly divided into SHR control group, SHR + NaHS (H(2)S donor) group and SHR + DL-propargylglycine (PPG) group, respectively. Another twenty-four male WKY rats were also divided into WKY control group, WKY + NaHS group and WKY + PPG group. SHR control and WKY control rats were injected with water. Rats of SHR + NaHS group and WKY + NaHS group were injected with NaHS, and rats of SHR + PPG group and WKY + PPG group were injected with PPG every day. Five weeks later, the blood pressure and the left-to-whole heart weight ratio were determined. The producing rate of H(2)S in aorta and the H(2)S level in plasma were also detected.

RESULTSThe producing rate of H(2)S in aorta and the plasma level of H(2)S in SHR groups were all less than those of the corresponding WKY groups, however, the differences between SHR + PPG group and WKY + PPG group were not significant (P > 0.05). The producing rate of H(2)S and the plasma level of H(2)S in SHR + PPG group were similar to those of SHR control group. The producing rate of H(2)S and the plasma level of H(2)S in SHR + NaHS group were higher than those of SHR control. Both the producing rate and the plasma level of H(2)S in WKY + PPG group were less than those of WKY control. The producing rate of H(2)S in aorta of WKY + NaHS group was higher than that of WKY controls, while the plasma level of H(2)S in WKY + NaHS group was not different from that of WKY controls significantly. The blood pressure of SHR groups increased compared with that of WKY groups (P < 0.05). The blood pressure of SHR + PPG group was similar to that of SHR controls, while the blood pressure of SHR + NaHS reduced significantly compared with that of SHR controls. The blood pressure of WKY + PPG group was higher than that of WKY controls while the blood pressure of WKY + NaHS was similar to that of WKY controsl.

CONCLUSIONSH(2)S plays an important role in maintaining normal pressure and the reduced production of endogenous H(2)S is an essential factor in the development of spontaneous hypertension. Exogenous H(2)S provides a new way for interfering with the progression of hypertension.