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Non steroidal anti inflammatory drugs (NSAIDs) are efficacious in chemoprevention of colorectal cancer. Therefore, the potential ability of Etoricoxib, a selective cycloxygenase-2(COX-2) inhibitor and Diclofenac, a preferential COX-2 inhibitor are considered in the chemoprevention of 1, 2-dimethylhydrazine (DMH) induced colon carcinogenesis in rat model. DMH was injected s.c. for six weeks while Etoricoxib and Diclofenac were fed daily orally alone and also in combination with an weekly subcutaneous injection of 1,2-dimethylhydrazine dihydrochloride (DMH) to the rats. After the treatment period of 6 weeks the animals were sacrificed by an overdose of ether anesthesia and the colonic tissues were removed and studied by the FTIR and NMR Spectroscopic techniques to evaluate the changes occurring in the lipid bilayer of colonic membrane lipids. The alterations in wave number of FTIR spectra as well as the chemical shifts of NMR spectra were recorded which signify the modulation of membrane lipids during colon carcinogenesis and possible cancer prevention by the oral administration of NSAIDs in an experimental model of chemical induced colon carcinogenesis.Los fármacos antiinflamatorios no esteroideos (AINE) son eficaces en la prevención del cáncer colorrectal. Por lo tanto, la capacidad potencial de Etoricoxib, un inhibidor selectivo de la ciclooxigenasa-2(COX-2), y de Diclofenaco, un inhibidor preferencial de la COX-2, se considera en la quimioprevención de la carcinogénesis de colon inducida por 1, 2-dimetilhidracina (DMH) en el modelo murino. Se inyectó s.c. DMH durante 6 semanas a la vez que se administraban diariamente por vía oral Etoricoxib y Diclofenaco solos y en combinación con una inyección s.c. semanal de dihidrocloruro de 1,2-dimetilhidracina (DMH) a las ratas. Después del período de tratamiento de 6 semanas, se sacrificó a los animales mediante una sobredosis de anestesia con éter y se extirpó el tejido colónico para estudio con las técnicas espectroscópicas FTIR y NMR para evaluar los cambios que ocurrieron en la bicapa lipídica de las membranas lipídicas colónicas. Se registraron las alteraciones en el número de onda del espectro FTIR así como las desviaciones químicas del espectro NMR, lo que significa la modulación de los lípidos de membrana durante la carcinogénesis colónica y la posible prevención del cáncer mediante la administración de AINE por vía oral en un modelo experimental de carcinogénesis colónica inducida por un agente químico.

Etoricoxib, a second generation selective cyclooxygenase-2 (COX-2) inhibitor had been studied for the chemopreventive response at its therapeutic anti-inflammatory dose in 1,2-dimethylhydrazine (DMH) induced colon carcinogenesis in rat model. Eight to ten weeks old male rats of Sprague-Dawley strain were divided into four groups. While group 1 served as control and received the vehicle of the drugs, group 2 and 3 were administered freshly prepared DMH in 1mM EDTA-saline (pH 7.0) (30 mg/kg body wt/week, subcutaneously). Group 3 was also given a daily treatment of etoricoxib (0.6 mg/kg body wt orally) while the group 4 received the same amount of etoricoxib only, prepared in 0.5% carboxymethyl cellulose. Animals were sacrificed at the end of 6 weeks, body weight recorded and the colons were subjected to macroscopic and histopathological studies. The maximum number of raised mucosal lesions called the multiple plaque lesions (MPL) were found in the DMH group which significantly reverted back in the DMH + etoricoxib group, while very few MPLs were recorded in the control and etoricoxib only group. Similarly, the number of aberrant crypt foci (ACF), the point of future carcinogenic growth, was recorded more in the DMH group and significantly less in the DMH + etoricoxib group. The histopathological analysis showed the presence of severe hyperplasia, occasional dysplasia and aggregates of lymphoid cells in the localized regions. Etoricoxib group showed near normal histological features with the crypt architecture and the surrounding stromal tissue remaining intact. To ascertain the molecular mechanism of such anti-carcinogenic features the colonocytes were isolated and studied in primary culture for the evidence of apoptosis by fluorescent staining and genotoxic changes by single cell gel electrophoresis assay (comet assay) which shows that the DMH treated animals produced much less apoptotic nuclei but more comet producing cell, while these features were reverted back with the etoricoxib treatment. The cytoplasmic expression of COX-2 protein was studied in paraffin sections of the colon by immunohistochemistry with COX-2 specific antibody which showed a very high presence of this inducible enzyme with the DMH group while in all other groups of animals it was not visible or weekly expressed. The anti-inflammatory effect of the drug, etoricoxib was also validated by a carrageenan-induced inflammation in rat model which showed an extremely high anti-inflammatory response within the dose range used in the present study. Also the growth profile of all the animals remained the same throughout the six week period of the investigation as there was no change in the body weight. It appears that apoptosis remains the dominant anti-proliferative end effect of this drug, mediated by an inhibition of the proinflammatory COX-2 isoform although further molecular probings are needed to arrive at a conclusive agreement in favor of the chemoprotective use of such drugs in colon cancers.El Etoricoxib, un inhibidor selectivo de la ciclooxigenasa-2 (COX-2) de segunda generación, se ha estudiado por la respuesta quimiopreventiva a su dosis terapéutica antiinflamatoria en un modelo murino de carcinogénesis colónica inducida por 1,2-dimetilhidracina (DMH). Se dividió en cuatro grupos a ratas de la cepa Sprague-Dawley de ocho a diez semanas de vida. El grupo 1 sirvió de control y recibió el vehículo de los fármacos, y a los grupos 2 y 3 se les administró DMH recién preparada en EDTA-salino al 1 mM (pH 7,0) (30 mg/kg peso corporal/semana, subcutáneamente). El grupo 3 también recibió a diario tratamiento con etoricoxib (0,6 mg/kg peso corporal, por vía oral), mientras que el grupo 4 solamente recibió la misma cantidad de etoricoxib, preparado en 0,5% carboximetil celulosa. Se sacrificó a los animales al final de la sexta semana, se registró el peso corporal y se realizaron estudios macroscópicos e histopatológicos del colon. El número máximo de lesiones mucosas elevadas, denominadas lesiones en placa múltiples (LPM) se halló en el grupo DMH, y estaba significativamente normalizado en el grupo de DMH + etoricoxib, mientras que se hallaron muy pocas lesiones LPM en los grupos control y con sólo etoricoxib. De forma similar, el número de focos de criptas aberrantes (FCA), el punto del futuro crecimiento carcinogénico, se registró más abundantemente en el grupo DMH y menos significativamente en el grupo DMH + etoricoxib. El análisis histopatológico mostró la presencia de una hiperplasia marcada, displasia ocasional y agregados de células linfoides en las regiones localizadas. El grupo de etoricoxib mostró unas características histológicas casi normales, permaneciendo la arquitectura de las criptas y el tejido estromal vecino intacto. Para determinar el mecanismo molecular de tales hallazgos anticarcinogénicos, se aislaron los colonocitos y se estudiaron en un cultivo primario para evidencia de apoptosis mediante tinción fluorescente y cambios genotóxicos en un ensayo de electroforesis en gel de una única célula (ensayo comet), que mostró que los animales tratados con DMH produjeron muchos menos núcleos apoptóticos pero un mayor número de células productoras de comet, mientras que estos cambios revirtieron con el tratamiento con etoricoxib. Se estudió la expresión citoplásmica de la proteína COX-2 en las secciones en parafina del colon mediante inmunohistoquímica con un anticuerpo específico anti-COX-2 que mostró una presencia muy alta de esta enzima inducible en el grupo DMH mientras que en el resto de los grupos de animales apenas se expresó o no se visualizó. Efecto antiinflamatorio del fármaco: el etoricoxib también se validó en modelo murino de inflamación inducida por carragenina que mostró una respuesta antiinflamatoria extremadamente alta dentro del rango de dosis empleado en este estudio. El perfil de crecimiento de los animales permaneció inalterado durante las seis semanas que duró la investigación y no hubo cambios en el peso corporal. Parece que la apoptosis sigue siendo el efecto antiproliferativo final dominante de este fármaco mediado por la inhibición de la isoforma proinflamatoria de la COX-2, si bien se necesitan probandos moleculares adicionales para llegar a un acuerdo concluyente a favor del uso quimiopreventivo de tales fármacos en los cánceres de colon.

The present study was designed to evaluate the effects of three non-steroidal anti-inflammatory drugs (NSAIDs) with varying cycloxygenase selectivities on the small intestinal biochemical composition, function and histology during 1, 2-dimethylhydrazine (DMH) administration. Sprague Dawley male rats were divided into five different groups viz: Group 1 (control, vehicle treated), Group 2 (DMH-treated, 30 mg/kg body weight/week in 1 mM EDTA-saline, subcutaneously), Group 3 (DMH + aspirin-60 mg/kg body weight), Group 4 (DMH + celecoxib-6 mg/kg body weight), Group 5 (DMH + etoricoxib-0.64 mg/kg body weight). After six weeks of treatment, brush border membrane was isolated from the jejunum segment of all the groups and changes in the associated enzymes such as sucrase, lactase, maltase, alkaline phosphatase, membrane lipid composition, fluorescence polarizations of diphenylhexatriene, pyrene excimer formation, histological changes and surface characteristics were studied. The results indicated a significant alteration in the enzyme activity as well as changes in the structure and function of the intestine in the presence of the pro-carcinogen, DMH, which suggests the possible chemopreventive efficacy of NSAIDs against the intestinal cancer.El presente estudio se diseñó para evaluar los efectos de tres fármacos antiinflamatorios no esteroideos (AINE) con diferente selectividad por la ciclooxigenasa sobre la composición bioquímica, la función y la histología del intestino delgado durante la administración de 1,2-dimetilhidracina (DMH). Se distribuyó a ratas macho Sprague Dawley en grupos distintos: Grupo 1 (control, tratado con vehículo), Grupo 2 (tratado con DMH, 30 mg/kg de peso /semana en 1 mM de EDTA-salino, subcutáneo), Grupo 3 (DMH + aspirina-60 mg/kg de peso), Grupo 4 (DMH + celecoxib-6 mg/kg de peso), Grupo 5 (DMH + etoricoxib-0,64 mg/kg de peso). Tras seis semanas de tratamiento, se aisló la membrana en cepillo de un segmento del yeyuno en todos los grupos y se estudiaron los cambios en las enzimas asociadas tales como sucrasa, lactasa, maltasa, fosfatasa alcalina, en la composición lipídica de la membrana, las polarizaciones de fluorescencia del difenilhexatrieno, la formación del excímero pireno, los cambios histológicos y las características de la superficie. Los resultados indican una alteración significativa de la actividad enzimática así como cambios en la estructura y función del intestino en presencia del procarcinógeno DMH, lo que sugiere la posible eficacia quimio-preventiva de los AINE frente al cáncer de intestino.

A liquid chromatography-tandem mass spectrometry method with atmospheric pressure chemical ionization (LC-APCI/MS/MS) was validated for the determination of etoricoxib in human plasma using antipyrin as internal standard, followed by on-line solid-phase extraction. The method was performed on a Luna C18 column and the mobile phase consisted of acetonitrile:water (95:5, v/v)/ammonium acetate (pH 4.0; 10 mM), run at a flow rate of 0.6 mL/min. The method was linear in the range of 1-5000 ng/mL (r²>0.99). The lower limit of quantitation was 1 ng/mL. The recoveries were within 93.72-96.18%. Moreover, method validation demonstrated acceptable results for the precision, accuracy and stability studies.

It has been estimated that 30 million people worldwide take an nonsteroidal antiinflammatory drug (NSAID) daily. The main clinical objectives of these drugs are both to reduce joint pain and to improve joint function. However, gastrointestinal adverse events lead to the development of cyclooxygenase selective inhibitors (COXIB) with a better gastrointestinal safety profile. Since 1999, COXIB shown capacity to develop cardiovascular adverse events. Subsequent discoveries confirm overall risk of cardiovascular events. The increased cardiovascular risk occurred both in patients who were taking aspirin and in those who were not. Similar results with different COXIB appears to be a class effect of the COX-2 inhibitors, so patient risk factors must be identified and used in treatment decision making. Patients with gastrointestinal risk factors and no cardiovascular risk may benefit from use of a gastroprotective agent plus a nonselective nonsteroidal antiinflammatory drugs as a COXIB. We review assays whose objective was to study cardiovascular security of nonsteroidal antiinflammatory drugs and COXIB for known advantages and limitations of these drugs.