Standardization of Caco-2 cell culture as in vitro model for intestinal permeability

The aim of this study was to find out the optimal experimental conditions for Caco-2 cell culture (time and density) and permeability assays (diffusion system and drug concentration) in order to study the in vitro drugs permeability as a predictive method for drug absorption across intestinal epithelium. The integrity of the monolayers used in each assay was determined by measuring the transepithelial electrical resistance (TEER) and the permeability of the atenolol-a drug which is transported across the monolayers by the paracellular pathway-. The best working condition was obtained with a cell seeding of 7.104 cells/insert in a vertical difussion chamber. In such context, the monolayers had a TEER higher than 550 Ω.cm2 and the apparent permeability coefficient of atenolol was 0.71 ± 0.19 x 10-6 cm/seg.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Ischemic Tolerance Protects the Rat Retina from Glaucomatous Damage

Glaucoma is a leading cause of acquired blindness which may involve an ischemic-like insult to retinal ganglion cells and optic nerve head. We investigated the effect of a weekly application of brief ischemia pulses (ischemic conditioning) on the rat retinal damage induced by experimental glaucoma. Glaucoma was induced by weekly injections of chondroitin sulfate (CS) in the rat eye anterior chamber. Retinal ischemia was induced by increasing intraocular pressure to 120 mmHg for 5 min; this maneuver started after 6 weekly injections of vehicle or CS and was weekly repeated in one eye, while the contralateral eye was submitted to a sham procedure. Glaucoma was evaluated in terms of: i) intraocular pressure (IOP), ii) retinal function (electroretinogram (ERG)), iii) visual pathway function (visual evoked potentials, (VEPs)) iv) histology of the retina and optic nerve head. Retinal thiobarbituric acid substances levels were assessed as an index of lipid peroxidation. Ischemic conditioning significantly preserved ERG, VEPs, as well as retinal and optic nerve head structure from glaucomatous damage, without changes in IOP. Moreover, ischemia pulses abrogated the increase in lipid peroxidation induced by experimental glaucoma. These results indicate that induction of ischemic tolerance could constitute a fertile avenue for the development of new therapeutic strategies in glaucoma treatment