Role of cyclooxygenases in radiation enteropathy / 药学实践杂志

Gastrointestinal tract is one of the most sensitive organs exposed to ionizing radiation .Radiation enteropathy is a hot topic in radiobiological field .Cumulative evidences demonstrated that cyclooxygenases (COXs) might contribute sub-stantially to attenuating intestinal damage provoked by irradiation .The role of cyclooxygenases in radiation-induced intestinal damage was reviewed in this paper .

Interrelación del equilibrio tromboxano A2-prostaciclina y su modificación cuando se ingiere aspirina / Interrelation of the balance tromboxano A2-prostaciclina and its modification when aspirin is ingested

Introducción: la aspirina, es usada por su acción antiinflamatoria, analgésica, antipirética y antiagregante plaquetaria. El conocimiento del metabolismo del ácido araquidónico es fundamental para el estomatólogo que basa su trabajo en diagnosticar y tratar procesos inflamatorios en tejidos bucodentales, también por su condición de cirujano debe estar alerta en no realizar intervenciones quirúrgicas en pacientes que estén tomando aspirina, por interrumpir este medicamento la agregación plaquetaria, importante paso de la hemostasia normal. Objetivo: interpretar la interrelación hemostática del tromboxano A2 y la prostaciclina en condiciones fisiológicas, y el resultado de su modificación cuando se ingiere aspirina. Método: PubMed fue empleada como fundamental fuente de búsqueda, que incluyó el conocimiento sobre el fármaco aspirina, la interacción del tromboxano y la prostaclina, y la acción que sobre el equilibrio de estos productos ejerce la aspirina; también se revisaron HINARI, LILACS y Medline. Desarrollo: el ácido araquidónico es un ácido graso poliinsaturado de 20 átomos de carbono (ácido 5, 8, 11, 14-eicosatetraenoico) que procede directamente de la dieta. La relación recíproca entre PG-I2 y el TxA2 constituye un mecanismo finamente equilibrado que sirve para regular la función plaquetaria del ser humano. La utilidad de la aspirina en los pacientes expuestos a trombogénesis se debe, en gran parte, a su capacidad para inhibir la síntesis del TxA2, agente derivado del ácido araquidónico, elemento que se encuentra esterificado a los fosfolípidos de la membrana plaquetaria. El óxido nítrico, igual que la PG-I2, actúa también como vasodilatador e inhibidor de la agregación plaquetaria. Conclusiones: los pacientes que acuden al estomatólogo y por prescripción facultativa están tomando aspirina, tienen su sistema plaquetario inhibido y no pueden sintetizar tromboxano. El proceder quirúrgico por parte del estomatólogo en un paciente que esté ingiriendo aspirina lo expone al desarrollo de hemorragia de causa iatrogénica(AU)

Introduction: aspirin is used by its arachidonic acid is fundamental for the dentist that bases its work on diagnosis and treatment of inflammatory processes, also for its surgeon condition he should be alert to do not carry out surgical interventions in patients that are taking aspirin, because this drug interrupts platelet aggregation, important step of the normal hemostasis. Objective: to interpret the hemostatic interrelation of the tromboxano A2 and the prostaciclina in physiologic conditions and the result of their modification when aspirin is ingested. Method: it was employee as fundamental search source the PubMed, other databases also revised they were HINARI, LILACS, Medline. Was carried out a search that included the knowledge on the drug aspirin, the interaction of the tromboxano and the prostaclina, and the action that it has more than enough the balance of these products it exercises the aspirin. Development: the arachidonic acid is a polyunsaturated fatty acid of 20 atoms of carbon (5, 8, 11, 14-eicosatetraenoic acid) that proceeds directly from diet. The reciprocal relationship between PG-I2 and TxA2 constitutes a finely balanced mechanism that is good to regulate the human being's platelet function. The utility of aspirin in patients exposed to thrombogenesis is largely due to its capacity to inhibit the synthesis of the TxA2, agent derived from arachidonic acid, which is esterified to the phospholipids of the platelet membrane. Nitric oxide, the same as the PG-I 2, also acts as vasodilator and inhibitor of the platelet aggregation. Conclusions: the patients that go to the dentist and for medical prescription are taking aspirin, have their platelet system inhibited and cannot synthesize tromboxane. Surgical processes performed by the dentist in a patient that is ingesting aspirin exposes him to the development of hemorrhage of yatrogenic cause(AU)

Docking studies on xanthones of mangosteen as cox-2 inhibitors.

The prostaglandins found in most of the tissues and organs are synthesized by sequential oxidation of cyclooxygenases (COX-1 and COX-2). Prostaglandins synthesized by COX-1 are responsible for the protection of gastrointestinal tract and by COX-2 are responsible for inflammation and pain. The objective of this investigation was to characterize and determine the effect of α-mangostin, β-mangostin and γ-mangostin on COX-1 and COX-2. We have carried out the docking of α, β and γ-mangostin inhibitors into the three dimensional structure of COX-1 and COX-2 enzymes using GOLD software. The inhibitor binding positions and affinity were evaluated using GOLD scoring fitness functions. We identified that amino acid residues Leu52, Arg49, Val33 in COX-1 and Ala18, Ser23, Asp38, Cys22 in COX-2 are important for inhibitor recognition via hydrogen bonding interactions. These hydrogen bonding interactions play an important role for stability of the complex. This information can be exploited to design Mangostin based inhibitors. Our results may be helpful for further experimental investigations.

The effect of rosiglitazone in modulating cyclooxygenases-2 in nonalcoholic steatohepatitis rats / 中华消化杂志

Objective To evaluate the impact of rosiglitazone (Ros) on liver expression of peroxisome proliferator-activated receptor γ (PPARγ),nuclear factor (NF-κB) and cyclooxygenase-2(COX-2) in treatment of nonalcoholic steatohepatitis (NASH) rats.Methods Thirty Sprague-Dawley rats were divided into normal group,model group and Ros treated group with 10 each.Except the normal group,the other two groups were given high fat diet for 12 weeks for NASH model.The rats in Ros treated group were gavaged 4 mg/kg of Ros daily at the 12th week for 8 weeks.All rats were sacrificed at the 20th week for blood sample and liver tissue.Biochemical parameters of liver function,lipid metabolism,glycometabolism and antioxidant enzyme activities were measured.The histological change of the liver were assessed with HE and Masson staining.The level of tumor necrosis factor (TNF)-α and prostaglandin E2 (PGE2) was measured using ELISA.The expression of PPARγ,NF-κB and COX-2 was detected with immunohistochemistry.The mRNA and protein expressions of COX-2 were tested by real-time PCR and Western blotting,respectively.Results In comparison with model group,Ros treated group showed significant improvement in hepatic steatosis,inflammation and fibrosis(all P value<0.05).In model group,the serum levels of fasting blood glucose,insulin and HOMA-insulin resistance index (HOMA-IRI),total cholesterol (TC),total triglyeride (TG),lowdensity lipoprotein cholesterol (LDL-C) and free fatty acids were increased,but HDL-C level was decreased.All above parameters markedly improved after Ros treatment.The levels of ALT and AST,total anti-oxidation competence,superoxide dismutase,catalase,glutathione peroxidase and malondialdehyde in Ros treated group were significantly ameliorated when compared with those in model group.Immunohistochemistry showed that the expression of NF-κB and COX-2 was significantly elevated,but PPARγ was decreased in model group.Real-time PCR and Western blot revealed that the mRNA and protein expressions of COX-2 were higher in the model group than those in normal group (0.57±0.08 vs 0.38±0.03;2.83±0.24 vs 1.00±0.03,P=0.000 and P=0.004,respectively),but significantly lower in Ros treated group (0.55±0.06 and 1.84±0.13,P<0.01).Conclusions Ros can reduce oxidative stress and insulin resistance in NASH rats by activing PPARγ expression and inhibiting expression of NF-κB and cyclooxygenases.