Protective effects of betaxolol in eyes with kainic acid-induced neuronal death.
In the present study, we investigated whether betaxolol, a selective beta1-adrenoceptor antagonist, has neuroprotective effect on kainic acid (KA)-induced retinal damage. Neurotoxicities were induced in adult male rats by intravitreal injection of KA (total amount, 6 nmol). To examine the neuroprotective effects of betaxolol, rats were pretreated with betaxolol topically 60 min before KA injection to the rat eyes and twice daily for 1, 3, and 7 days after KA injection. The neuroprotective effects of betaxolol were estimated by measuring the thickness of the various retinal layers, and by counting the number of choline acetyltransferase (ChAT)- and tyrosine hydroxylase (TH)-positive cells in each retinal layer. The retina is highly vulnerable to KA-induced neuronal damage. Morphometric analysis of retinal damage in KA injected eyes, the thickness of the retinal layers decreased markedly after KA injection period of both 3 and 7 days. Furthermore, the numbers of ChAT- and TH-positive cells were significantly reduced by intravitreal injection of KA. However, when two drops of betaxolol, once before KA injection and twice daily for 7 days after KA injection, were continuously administered, the reductions in the retinal thickness and the retinal ChAT- and TH-positive cells were significantly attenuated. The present study suggests that topically applied betaxolol has neuroprotective effect on the retinal cell damage due to KA-induced neurotoxicity.
Cheon
Eun Woo
EW
Division of Food Science, Jinju International University, 270 San Sangmun-ri Munsan-eup, Jinju, Kyungnam 660-759, South Korea.
Park
Chang Hwan
CH
Kim
Yoon Sook
YS
Cho
Chang Hyun
CH
Chung
Young Chul
YC
Kwon
Jong Gil
JG
Yoo
Ji Myong
JM
Choi
Wan Sung
WS
Cho
Gyeong Jae
GJ
D000704:Analysis of Variance; D000818:Animals; D015784:Betaxolol / Q000008:administration & dosage*; D002452:Cell Count / Q000379:methods; D016923:Cell Death / Q000187:drug effects; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D004195:Disease Models, Animal; D004333:Drug Administration Routes; D004334:Drug Administration Schedule; D007150:Immunohistochemistry / Q000379:methods; D007608:Kainic Acid; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000378:metabolism / Q000473:pathology; D012164:Retinal Diseases / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D018696:Neuroprotective Agents; D014446:Tyrosine 3-Monooxygenase; D002795:Choline O-Acetyltransferase; D015784:Betaxolol; D007608:Kainic Acid