OBJECTIVETo investigate the impact of sodium nitroprusside (a nitric oxide donor) in the ductus arteriosus in preterm rabbits on hydrogen sulfide (H(2)S)-cystathionine-γ-lyase (CSE) system.

METHODSFor 16 Japanese white rabbits pregnant for 21 days were randomly divided into four groups, each of the following groups had 4 rabbits: control group, intraperitoneal injection of sodium nitroprusside 1 mg/kg, 2.5 mg/kg, and 5.0 mg/kg groups. The rabbits in control group had a peritoneal puncture with a simple hollow needle, and those in the other groups were given corresponding dose of intraperitoneal injection of sodium nitroprusside at gestational age 23 and 25 days, respectively. At gestational age 26 days the fetuses of the pregnant rabbits were removed surgically, and 28 fetal rabbits were obtained from the control group, 27 from the sodium nitroprusside small dose group, 29 from the medium dose group, and 26 from the large dose group. The fetal heart blood sample of 1 ml was taken from each fetus, and immediately after sampling the arterial ductal tissues were dissected. Fetal rabbit plasma proteins hydrogen sulfide content was determined by using de-protein method, and real time quantitative RT-PCR was used for determination of arterial tissue CSE gene and western-blotting was used for measuring protein expression of CSE.

RESULTSIn control group hydrogen sulfide content of fetal rabbits plasma (55.68 ± 6.57) µmol/L and arterial tissue CSE mRNA expression was 1.07 ± 4.12; the parameters in intraperitoneal injection of sodium nitroprusside group 1 mg/kg were (60.02 ± 6.09) µmol/L and 3.46 ± 0.18; in intraperitoneal injection of sodium nitroprusside group 2.5 mg/kg, were (64.71 ± 7.12) µmol/L and 10.95 ± 0.22; and in intraperitoneal injection of sodium nitroprusside group 1 mg/kg were (70.63 ± 8.07) µmol/L and 19.56 ± 0.17. Comparison between small dose group and control group, medium dose group and small dose group, high dose group and medium dose group showed that the above data were significantly different P < 0.05, with the injection of sodium nitroprusside CSE protein expression increased gradually with increasing doses.

CONCLUSIONSodium nitroprusside showed an enhancing effect on preterm CSE-H(2)S system in rabbit ductus arteriosus in a certain range of concentration in a dose-dependent manner.