POLYMORPHONUCLEAR LEUKOCYTE INFILTRATION INTO THE SUBRETINAL CHOROID AND OPTIC-NERVE IN RESPONSE TO LEUKOTRIENES

Purpose. To describe the pattern of leukocyte infiltration in ocular a nterior and posterior segment tissues in response to local administrat ion of LTB4 and LTD4. Methods. Leukocyte infiltration after intravitre al administration of LTB4 or LTD4 was assessed in ocular sagittal cros s-sections and compared with vehicle-treated control eyes. Results. A dose-dependent eosinophil infiltration was observed in the subretinal choroid and the ora serrata region of the ciliary body in response to both LTB4 and LTD4, but only LTB4 behaved as a chemoattractant for neu trophils. Subretinal eosinophils achieved Bruch's membrane in response to LTB4 but, though gathered in several foci, this important barrier was not breached and leukocytes did not reach the neural retina. Eosin ophils and some neutrophils also achieved the optic disc in response t o LTB4. Tissue damage to the optic nerve head coincided with the prese nce of degranulating eosinophils, indicating that visual impairment ma y result from damage to the optic nerve head, with the retina left int act. Apart from the ora serrata and pars plana, no leukocyte infiltrat ion in other anterior segment tissues-such as the pars plicata, ciliar y process, or iris proper-was apparent. Conclusions. It appears that t he ingress of leukocytes into intraocular tissues of the eye in respon se to leukotrienes is discretely regulated, probably at the level of t he vasculature.