ABSTRACT
To study spontaneous intraocular hemorrhage in rats during postnatal ocular development and to elucidate the underlying mechanism, postnatal ocular development in the albino Wistar Hannover (WH) and Sprague-Dawley (SpD) and pigmented Long-Evans (LE) strains was analyzed. Pups (n = 2 to 5) from each strain were euthanized daily on postnatal days (PND) 0 through 21 and their eyes examined macroscopically and histologically; similar analyses were performed in 26 to 39 additional WH pups daily from PND 7 to 14. At necropsy, ring-shaped red regions and red spots were present in the eyes of WH and SpD rats. These lesions were attributed histologically to hemorrhage of the tunica vasculosa lentis or of the retina, choroid, and hyaloid artery, respectively. Similar intraocular hemorrhages occurred in LE rats, although the macroscopic alterations found in WH and SpD rats were not present in this strain. Among the 3 strains evaluated, the incidence of the intraocular hemorrhage was highest in WH rats. We here showed that intraocular hemorrhage occurs spontaneously during normal ocular development in rats regardless of the strain; however, the region, degree, and incidence of intraocular hemorrhage differ among strains. Hemorrhage in the tunica vasculosa lentis and hyaloid artery may result from the leakage of erythrocytes from the temporary vasculature of these tissues during regression. The mechanisms underlying hemorrhage in the retina and choroid remain unclear. To our knowledge, this report is the first to describe the spontaneous intraocular hemorrhage that occurs during postnatal ocular development in rats.
Subject(s)
Choroid Hemorrhage/veterinary , Eye/growth & development , Eye/pathology , Retinal Hemorrhage/veterinary , Rodent Diseases/pathology , Age Factors , Animals , Animals, Newborn , Choroid Hemorrhage/etiology , Choroid Hemorrhage/pathology , Eye/blood supply , Rats , Rats, Long-Evans , Rats, Sprague-Dawley , Rats, Wistar , Retinal Hemorrhage/etiology , Retinal Hemorrhage/pathology , Rodent Diseases/etiology , Severity of Illness Index , Species SpecificityABSTRACT
It is known from earlier studies that the so-called K-protozoa, the late presporogonic stages of Sphaerospora renicola, a parasite causing renal sphaerosporosis in common carp (Cyprinus carpio), accumulate in the swimbladder wall and give rise to the disease called myxosporean swimbladder inflammation. The present study indicates that in the case of intensive infection these parasites also occur in the rete mirabile of the choroid of the eye, causing haemorrhages and necrosis. The results suggest that the K-stages of S. renicola are located in the blood path just like the early presporogonic C-stages; however, as they get stuck in organs rich in capillaries, it is difficult to demonstrate them from the blood of the common carp.
