Evaluation of protein undernourishment on the condylar process of the Wistar rat mandible correlation with insulin receptor expression

The mandible condylar process cartilage (CP) of Wistar rats is a secondary cartilage and acts as a mandibular growth site. This phenomenon depends on adequate proteins intake and hormone actions, including insulin. Objectives The present study evaluated the morphological aspects and the expression of the insulin receptor (IR) in the cartilage of the condylar process (CP) of rats subjected to protein undernourishment. Material and Methods The nourished group received a 20% casein diet, while the undernourished group (U) received a 5% casein diet. The re-nourished groups, R and RR, were used to assess the effects of re-nutrition during puberty and adulthood, respectively. CPs were processed and stained with picro-sirius red, safranin-O and azocarmine. Scanning electron microscopy and immunohistochemistry were also performed. Results The area of the CP cartilage and the number of cells in the chondroblastic layer decreased in the U group, as did the thickness of the CP layer in the joint and hypertrophic layer. Renourishment during the pubertal stage, but not during the adult phase, restored these parameters. The cell number was restored when re-nutrition occurred in the pubertal stage, but not in the adult phase. The extracellular matrix also decreased in the U group, but was restored by re-nutrition during the pubertal stage and further increased in the adult phase. IR expression was observed in all CPs, being higher in the chondroblastic and hypertrophic cartilage layers. The lowest expression was found in the U and RR groups. Conclusions Protein malnutrition altered the cellularity, the area, and the fibrous cartilage complex, as well as the expression of the IRs. .

Involvement of p38 Mapkinase in attenuation of antinociceptive effect of morphine in diabetic mice.

Experimental diabetes induced by streptozotocin (200 mg/kg, ip) markedly decreased the antinociceptive effect of morphine and significantly increased the urinary nitrite concentration. Administration of FR-167653 (a selective p38MAPKinase inhibitor) in a dose of 4 mg/kg improved the antinociceptive effect of morphine and attenuated the increase in urinary nitrite concentration in diabetic mice. It may be concluded that diabetes-induced decrease in antinociceptive effect of morphine may be due to induction of p38 MAPKinase activity.

Inhibidores selectivos de la COX-2 (ISC-2): evidencias actuales sobre su real eficacia y seguridad / COX-2 selective inhibitors (C2SI): update evidence of their efficacy and safety

A principios de la década pasada, fueron descubiertas dos isoformas de la enzima ciclooxigenasa, encargada de catalizar la producción de postaglandinas a partir del ácido araquidónico. La COX-1, expresada en forma constitutiva a nivel gastrointestinal, renal y plaquetario, y la COX-2, enzima principalmente inducible en proceso como la inflamación, el dolor y la fiebre. Numerosos estudios, han demostrado tanto la eficacia, como la seguridad gástrica y plaquetaria de los inhibidores selectivos de la COX-2, en estudios fase II y en estudios clínicos fase III. Basados en estos estudios, en 1999 fueron aprobados por la FDA, dos inhibidores selectivos, celecoxib y refecoxib, para su uso en pacientes con artrosis y artritis reumatoídea. Estos fármacos se encuentran también disponibles en nuestro país. Estudios recientes demuestran, sin embargo, que ambas isoformas de COX, participarían en el proceso inflamatorio, y por lo tanto, su eficacia analgésica y antiinflamatoria, serían menor a la obtenida con los antiinflamatorios no esteroidales tradicionales. Por otro lado, tanto a nivel gástrico como renal se ha visto participación de la COX-2 en procesos fisiológicos, como la resolución de la inflamación en mucosas dañadas y en la embriogénesis renal en ratas. Por último, existen varias evidencias que demuestran funciones fisiológicas de la COX-2, en sitios tan disímiles como el sistema nervioso central y el colon. En estas localizaciones ha sido implicada en la patogenia de la enfermedad de Alzheimer y del cáncer de colon, lo que abre la posibilidad de desarrollar nuevas líneas de investigación, destinadas a encontrar nuevos tratamientos para éstas y otras patologías

Enzyme selectivity of new cyclooxygenase-2/5 lipoxygenase inhibitors using molecular modeling approach.

We have studied the conformational flexibility of three 5-keto-substituted 7-tert-butyl-2,3-dihydro-3,3-dimethylbenzofurans (DHDMBFs) which show dual cyclooxygenase (COX) and 5-lipoxygenase (LOX) inhibition and are potential candidates as antiinflammatory agents and analgesics. The conformations were studied by systematic search, molecular mechanics (MM) and simulated annealing molecular dynamics (SAMD) techniques. We also studied several structure based parameters and distribution of molecular electrostatic potential (MEP) around these molecules. All the three compounds were docked in the active cavity of cyclooxygenase-2 (COX-2) using graphical and energy grid search techniques. The complex geometries were optimized by MM. The results on conformational flexibility, inter-atomic distances and angles, MEP distribution and points of contacts with peptide side chains in active cavity have been used to understand the mechanistic cause of differential action of these molecules.