Effects of periocular administration of triamcinolone acetonide on leukocyte-endothelium interactions in the ischemic retina.
OBJECTIVE
Recent studies have reported that intravitreal or posterior sub-Tenon's injection of triamcinolone acetonide (TA) is effective in the treatment of macular edema resulting from retinal microcirculatory disturbances such as diabetic retinopathy and retinal vein occlusion. The effects of periocular administration of TA on leukocyte-endothelium interactions were studied after transient retinal ischemia.


METHODS
Transient retinal ischemia was induced by temporary ligation of the optic nerve sheath for 60 minutes in male Long-Evans rats. After the induction of ischemia, experimental eyes received a periocular injection of TA (2 mg). In control animals, the same volume of saline was administered. Leukocyte dynamics were evaluated in the retinal microcirculation using acridine orange digital fluorography. Also, retinal thickness was studied by using optical coherence tomography and a histologic


METHODS
The retinal mRNA expression of P-selectin and intercellular adhesion molecule (ICAM)-1 was semiquantitatively studied with RT-PCR.


RESULTS
The leukocytes rolling along retinal vein linings increased after ischemia in the vehicle-treated rats (32.5 +/- 2.1 cells/min). No rolling leukocytes, however, were seen in the TA-treated rats. The number of accumulated leukocytes was significantly lower in the TA-treated rats (831 +/- 99 cells/mm2) than in the control (971 +/- 81 cells/mm2, P < 0.05). The treatment decreased the retinal thickness and the mRNA expression of P-selectin and ICAM-1.


CONCLUSIONS
The present study demonstrated that the periocular injection of TA effectively decreased retinal thickness and inhibited leukocyte-endothelium interactions in the retina after ischemia. Downregulation of adhesion molecules of retinal vascular endothelium induced by TA may play a role in the course.
Mizuno
Shimon
S
Department of Ophthalmology and Visual Sciences, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan. simon@pp24.so-net.ne.jp
Nishiwaki
Akiko
A
Morita
Hiroshi
H
Miyake
Takatomo
T
Ogura
Yuichiro
Y
D000165:Acridine Orange; D000818:Animals; D002450:Cell Communication / Q000187:drug effects; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000378:metabolism*; D005456:Fluorescent Dyes; D015870:Gene Expression; D005938:Glucocorticoids / Q000008:administration & dosage*; D007267:Injections; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics; D007511:Ischemia / Q000150:complications*; D007962:Leukocytes / Q000378:metabolism*; D008269:Macular Edema / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism; D008297:Male; D019007:P-Selectin / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D012164:Retinal Diseases / Q000150:complications; D012171:Retinal Vessels; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014222:Triamcinolone Acetonide / Q000008:administration & dosage*
D005456:Fluorescent Dyes; D005938:Glucocorticoids; D019007:P-Selectin; D012333:RNA, Messenger; D018799:Intercellular Adhesion Molecule-1; D000165:Acridine Orange; D014222:Triamcinolone Acetonide