Ocular Blood Flow and Vascular Permeability in Endotoxin-Induced Inflammation

Abstract

Blood flow was measured in several tissues of the rabbit eye following intravitreal injection of a dose of endotoxin that induces an inflammatory response. In separate experiments, the vascular permeability of the inflamed eye was estimated by iris fluorescein angiography and by measuring protein influx into the aqueous humor. The effect of topical corticosteroid treatment upon blood flow and vascular permeability was also measured. Following intravitreal endotoxin injection, minor changes in blood flow occurred in retina and optic nerve head. Marked changes were observed in blood flow in iris, ciliary processes, and choroid. Steroid treatment had no effect upon the increased blood flow 24 h after the endotoxin injection, although from a clinical standpoint the steroid-treated eyes appeared less inflamed. Fluorescein angiography demonstrated a massive increase in iris vessel permeability 6 and 24 h following endotoxin injection. Topical steroid treatment reduced fluorescein entry into the anterior chamber at both time periods. On the other hand, the increase in protein influx into the aqueous humor in the endotoxin-inflamed eye was not inhibited by steroid pretreatment. It is suggested that corticosteroids have a selective effect upon the permeability of different components of the blood-aqueous barrier, namely the ciliary processes and the iris vasculature.

Passive immunization with Pneumovax®23 and pneumolysin in combination with vancomycin for pneumococcal endophthalmitis

“…The interior of the eye is an immune privileged area. Far lower amounts of complement proteins are found inside the eye, even when the eye is inflamed due to infection [39,40]. Also, membrane-bound regulatory proteins in the eye block deposition of C3b (deposition involved in opsonophagocytosis of gram-positive bacteria) so that the complement pathway will not destroy self-tissue of the eye.…”

Effects of morphine on the expression of cytokines and inflammatory mediators in a rabbit model of endotoxin-induced experimental uveitis

“…However, expression levels of TNF-α, IL-1beta, PG2, and MPO were measured in iris and ciliary body samples. Previously, Green et al (4) observed transient elevations in iris, ciliary body, and choroidal blood flow using fluorescein angiography in rabbits with endotoxin-induced experimental uveitis.…”

“…LPS injection has been demonstrated to be valid as an experimental model of uveitis and can be performed via intraperitoneal, subcutaneous, intracameral, and intravitreal routes (4,5) . The intravitreal route (26) was chosen in the present study as numerous ocular alterations related to other methods have been reported in previus studies.…”

“…Experimentally, uveitis can induced by intravitreal lipopolysaccharide (LPS) injection (4,5) leading to inflammatory cell in filtration at four hours after injection, with peak inflammation between 18 and 24 hours later (4) . Acute inflammatory responses in uveitis are maintained by the action of molecular mediators which ABSTRACT leads to decreased active secretion of aqueous humor and increased vascular permeability (6,7) .…”

Polyamine and histopathological changes after unilateral endotoxin‐induced uveitis and its contralateral effects

“…dotoxin triggers a multitude of potential contributors to inflammation. For example, endotoxin increases vascular permeability (Green et al 1990), stimulates cells to synthesize and release prostaglandins (Bhattacherje 1980), activates the immune response characterized by cytokine release and an intense leukocyte infiltration (Hoekzema et al 1990;Cybulsky et al 1988). To my knowledge, nothing is reported about bilateral effects of unilaterally injected endotoxins.…”