Objective: Febrile seizures (FS) are the most common type of seizure disorders. Studies have found that there have respective changes of heme oxygenase (HO)/CO system and nitric oxide synthase (NOS)/NO system during FS. The present study was to explore the influence on expression of HO-1 mRNA and protein and content of CO after recurrent FS by NOS inhibitor N(omega)-nitro-L-arginine Methyl ester (L-NAME), in order to demonstrate a regulating role in HO/CO system by NO.
Methods: Forty-eight SD rats were randomly divided into 3 equal groups: FS group, undergoing intraperitoneal injection of normal saline (NS) and then bath in 45.2 degrees C hot water for 5 minutes every other day for 10 times, FS + L-NAME group, undergoing intraperitoneal injection of NOS inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) and then FS for 10 times, and control group, undergoing intraperitoneal injection of NS and then bath in 37.0 degrees C water. Twenty-four hours after the last bath blood was collected from the abdominal cardinal vein to measure the concentrations of plasma nitric oxide and carbon monoxide with spectrophotometer. The brains were taken out to be made into frozen slices to undergo HO-1 in situ hybridization to measure the mRNA expression of HO-1. The hippocampus was taken out to undergo Western blotting to measure the expression of HO-1 protein.
Results: The plasma CO concentration was higher by 94.5% in the FS group in comparison with that in the control group (P < 0.01). The plasma CO concentration of the FS + L-NAME group was higher by 63.18% than that of the control group (P < 0.05) and lower by 16.14% than in the FS group (P < 0.05). The HO-1 mRNA expression was significantly higher in the FS group than in the control group. The HO-1 mRNA expression of the in hippocampal neurons of the L-NAME was lower than that of the FS group, however, still higher than that of the control group. Western blotting showed that HO-1 protein was expressed in all 3 groups; the HO-1 protein expression of the FS group was higher by 208% than that of the control group; and the HO-1 protein expression of the FS + L-NAME group was higher by 115% than that of the control group (P < 0.01) and lower by 30.19% than that of the FS group (P < 0.01).