Influence of cyclooxygenase inhibitor on expression of nitric oxide synthase in rats with portal hypertension / 上海第二医科大学学报

ABSTRACT

Objective To determine the mechanism of nitric oxide synthase(NOS) and prostacyclin(PGI2) acting on splanchnic hyperdynamic circulation of portal hypertention(PHT). Methods Ninety-six Sprague-Dawley rats were divided into three groups, namely, intrahepatic portal hypertension(IHPH, n=31), prehepatic portal hypertension(PHPH, n=33) and sham-operated controls(SO, n=32). Animals of each group were received indomethacin(INDO) either on a short term or long term with saline as control. Portal venous pressure, together with the concentration of nitric oxide (NO) and PGI2 in serum was measured. The constitutive nitric oxide synthase(cNOS)and inducible nitric oxide synthase(iNOS)activity in the abdominal aorta and small intestine of these rats were detrmined by spectrophotometry method. RT-PCR was performed to measure the levels of iNOS and cNOS mRNA in the arteries and guts mentioned above. Results Although INDO decreased the concentration of PGI2 in serum, the long-term INDO-treated group restored splanchnic hyperdynamic circulation in both IHPH and PHPH rats, concomitant with enhanced expression of iNOS and concentration of NO(P0.05). Conclusion Overproduction of NO inducing hemodynamic abnormalities of PHT is synthesized principally by increase of iNOS. There may be a possible interaction between PGI2 and NO in hyperhemodynamics of PHT, while PGI2 may not be a mediator in the formation and development of hyperdynamic circulatory state.