Histological study of lacrimal gland acinar cells in albino rats following prolonged use of phenylephrine decongestant eye drops

Tears, secreted by the acini of lacrimal gland, keep the corneal epithelium moist, thas preserving the most refractive mechanism of the eye. The over use of over-the-counter decongestant ophthalmic solutions is nowadays a public practice. The aim of the present work was to study the possible histological changes in the acinar cells of the lacrimal gland in albino rats after prolonged use of phenylephrine decongestant eye drops. 24 adult female albino rats were divided equally into 2 experimental groups, a control and a treated group that was subjected to repeated daily instillation of 2-3drops of phenylephrine 2.5% ophthalmic solution twice daily for 3 months. The intraorbital lacrimal glands of both groups were processed for light microscopic examination of H and E-stained paraffin sections, and toluidine blue-stained semithjn sections. Electron microscopic examination was also done. lacrimal gland acini of the control group revealed tall pyramidal secretory cells bordering a central lumen and contained large numbers of lightly- stained secretory granules. In the treated group, various histological changes were manifested in different acini. Manifestations of enhanced secretion with enormous number of secretory granules, extruding from short cuboidal acinar cells, into the widely distended lumen were depicted. Sustained stimulation of phenylephrine to the adrenergic receptors on the acinar cell membrane is suggested to enhance exocytosis. Repeated episodes of stimulation, by phenylephrine, produced manifestations of exhaustions and depleted activity in acinar cells. These manifestations were represented by wide areas of granule-free cytoplasm with dense shrunken nuclei. This might be attributed to the relatively limited energy and protein synthetic reserve of the lacrimal acinar cells. Long-standing application of phenylephrine eye drops resulted in multiforcal histological alterations of lacrimal gland acinar cells, which may contribute to dry eye state by depleting the functional reserve of the lacrimal gland. More attention should he paid during the use of such drugs. Further work is needed to investigate the possible reversibility of lacrimal gland histological changes after stoppage of the drug

Ordenación muscular de los conductos lagrimales / Muscular order of lacrimal ducts

El mecanismo de la excreción lagrimal a través de las vías de drenaje, presenta numerosos interrogantes. En este trabajo se ha analizado a nivel microscópico, por medio de cortes seriados semigruesos, el comportamiento de las fibras musculares del orbicularis oculli y sus relaciones íntimas con las vías lagrimales, en fetos y embriones humanos. Nuestro estudio demuestra la existencia de un esfínter estriado en la zona de estrechamiento de la porción vertical de los canaliculus lacrimalis, lugar que se ha denominado en la literatura "angustia de Gerlach". Los haces musculares que conforman esta estructura esfinteriana proceden, según hemos podido constatar, por su dirección, orientación, origen y terminación, de tres grupos fibrilares distintos. Dos de ellos provienen de la pars lacrimalis de Duverney-Horner, uno supracanicular con dirección espiroídea y otro infracanalicular no descrito en la bibliografía. El tercer haz de fibras pertenece a la pars ciliaris de Riolano. Estos tres fascículos forman imágenes de entrecruzamiento en la porción inicial de las vías de drenaje lagrimal