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Abstract #8087 Published in IGR 4-3
Betaxolol, a beta-1-adrenoceptor antagonist, protects a transient ischemic injury of the retina
Cheon EW; Kim YH; Cho YY; Kim HJ; Kang SS; Cho GJ; Yoo JM; Song JK; Choi WSExperimental Eye Research 2002; 75: 591-601
In the present study, the authors investigated the protective effects of the topical beta-adrenoceptor antagonist Betoptic® (0.25% betaxolol) in the rat retina following the ischemic injury induced by a transient increase of intraocular pressure (IOP). Like other areas of the central nervous system, the retina is highly vulnerable to ischemic-induced injury. Ischemia was induced in the rat retina by raising the IOP above the systolic blood pressure for 60 minutes. After an ischemia/reperfusion, the thickness of the retinal layers and the immunoreactivities of choline acetyltransferase (ChAT), gamma-amino butyric acid (GABA) and tyrosine hydroxylase (TH) were examined. After a reperfusion period of seven days, the thickness of both the inner plexiform layer and inner nuclear layer was much decreased. After a reperfusion period of 14-28 days, the thickness of the outer nuclear layer decreased markedly. Moreover, the ChAT and TH immunoreactivity had almost completely disappeared in the retinas after seven days, while GABA immunoreactivity remained for 28 days. These results suggest that the inner retinal layers are more susceptible to ischemic-induced injury than the outer retinal layer. Histological examination demonstrated protective effects of betaxolol on ischemic-induced retinal damage, which was more substantial in the inner retinal layer. When two drops of betaxolol, once before ischemic injury and twice daily for 28 days after ischemia, were continuously administered, the reductions in the retinal ChAT, GABA and TH immunoreactivities were significantly attenuated. The present study suggests that topically applied betaxolol is an efficient neuroprotective agent and prevents the retinal cell damage induced by ischemic injury in rats.
Choi WS, MD, Department of Anatomy and Neurobiology, College of Medicine, Gyeongsang National University, 92 Chilam-dong, Chinju 660-751, South Korea. choiws@nongae.gsnu.ac.kr
Classification:
11.3.4 Betablocker (Part of: 11 Medical treatment > 11.3 Adrenergic drugs)
