Direct Detection of Reactive Nitrogen Species in Experimental Autoimmune Uveitis

PURPOSE: Demonstrate unequivocally the generation of nitric oxide in experimental autoimmune uveoretinitis by electron spin resonance spectroscopy (ESR) using ferrous iron complex of N-methyl-D-glucamine dithiocarbamate, (MGD)2-Fe2+, as a spin trap. METHODS: Experimental autoimmune uveitis was induced in Lewis rats, and at the peak of the intraocular inflammation, the animals received intravitreous injections of the spin trap. The retina and choroid dissected from the enucleated globes were subjected to ESR. Similarly, the retina and choroid obtained at the peak of experimental autoimmune uveo-retinitis (EAU) were placed in a vial containing luminal, and chemiluminescence was counted on a Packard liquid scintillation analyzer. RESULTS: The ESR three-line spectrum (g=2.04; a(N)=12.5 G) obtained was characteristic of the adduct [(MGD)2-Fe2+-NO]. The majority of this signal was eliminated by the inducible nitric oxide synthase (iNOS) specific inhibitor aminoguanidine injected inflamed retina was detected when compared with that of the non inflamed controls. The chemiluminescent activity was further increased two-fold by the addition of bicarbonate to the inflamed retina; the phenomenon is attributable only to the presence of a high steady-state concentration of peroxynitrite. CONCLUSIONS: The study shows an unequivocal presence of nitric oxide in EAU retina and choroid and the generation of peroxynitrite. High levels of these reactive nitrogen species generated in the inflamed retina and choroids are certain to cause irreversible tissue damage, especially at the susceptible sites such as photoreceptors.

Reactive oxygen species inactivation improves pancreatic capillary blood flow in caerulein-induced pancreatitis in rats

PURPOSE: Reactive oxygen species (ROS) inactivation was studied to determine alterations in the pancreatic capillary blood flow (PCBF) during caerulein-induced pancreatitis in rats. METHODS: A laser-Doppler flowmeter to measure PCBF and N-t-Butyl-Phenylnitrone (PBN) compound to inactivate ROS were used. Forty rats were divided in groups: 1) control; 2) caerulein; 3) PBN; 4) caerulein+PBN. Serum biochemistry and histopathological analyses were performed. RESULTS: PCBF measured a mean of 109.08 ± 14.54%, 68.24 ± 10.47%, 102.18 ± 10.23% and 87.73 ± 18.72% in groups 1, 2, 3 and 4, respectively. PCBF in groups 2 and 4 decreased 31.75 ± 16.79% and 12.26 ± 15.24%, respectively. Serum amylase was 1323.70 ± 239.10 U/l, 2184.60 ± 700.46 U/l, 1379.80 ± 265.72 U/l and 1622.10 ± 314.60 U/l in groups 1, 2, 3 and 4, respectively. There was a significant difference in the PCBF and serum amylase when compared groups 2 and 4. Cytoplasmatic vacuolation was present in groups 2 and 4. Otherwise, no qualitative changes were seen. CONCLUSION: ROS inactivation improves PCBF and minimizes the serum amylase increase during caerulein-induced pancreatitis. ROS effect may be one of the leading causative events in this model of acute pancreatitis.

OBJETIVO: A inativação de radicais livres (RL) foi estudada para determinar as alterações do fluxo capilar pancreático (FCP) na pancreatite aguda induzida por ceruleína em ratos. MÉTODOS: Um laser-Doppler fluxímetro determinou o FCP e o composto N-t-Butyl-Phenylnitrone (PBN), para inativar os RL, foi utilizado. Quarenta ratos foram divididos em 4 grupos: 1) controle; 2)ceruleína; 3) PBN; 4)ceruleína+PBN. Dosagens bioquímicas e análise histopatológica foram realizadas. RESULTADOS: O FCP foi em média 109.08 ± 14.54%, 68.24 ± 10.47%, 102.18 ± 10.23% e 87.73 ± 18.72% nos grupos 1, 2, 3 and 4, respectivamente. O FCP nos grupos 2 e 4 diminuíram em média 31.75 ± 16.79% e 12.26 ± 15.24%, respectivamente. A média da amilase sérica foi de 1323,70 ± 239.10 U/l, 2184,60 ± 700,46 U/l, 1379,80 ± 265,72 U/l e 1622,10 ± 314,60 U/l nos grupos 1, 2, 3 e 4, respectivamente. Observou-se diferença significante no FCP e na amilase sérica quando comparados os grupos 2 e 4. Vacuolização citoplasmática estava presente nos grupos 3 e 4. Não foram observadas outras alterações qualitativas. CONCLUSÃO: A inativação de RL melhorou o FCP e minimizou a elevação da amilase sérica na pancreatite aguda induzida por ceruleína. A presença de RL parece ser um evento precoce neste modelo de pancreatite aguda experimental.

THE SCAVENGING ROLE OF OXYGEN FREE RADICALS BY SALVIA MILTIORRHIZA / 中国药理学通报

Using Xanthine-Xanthine Oxidase system to generate superoxide ani-on, using H2O2 -Fe2 + system to generate hydroxyl radical, the role of scavenging oxygen free radical by Miltiorrhiza was studied by electron paramagnetic resonance and spin trapping. The result suggested that the scavenging rate of hydroxyl radical by Salvia Miltiorrhiza injection is 65%, and that of superoxide anion is 100%. This result suggests that scavenging cytotoxic oxygen free radicals may be one of important pharmacological mechanism of Salvia Miltiorrhiza.