Effects of timolol maleate eye drops on experimentally dilated cardiomyopathy and healthy rabbits.

Mitsuhiro Isaka, Reimi Hayashida, Yuumi Tamashima, Ryuji Araki

Open veterinary journal 2021 Jul-Sep

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Dilated cardiomyopathy (DCM) is the most frequently diagnosed cardiomyopathy in rabbits. Timolol maleate (nonselective beta-blockers), which reduces the heart rate (HR) and blood pressure, has been used for glaucoma. However, this effect has not been assessed in a rabbit DCM model. This study aimed to evaluate the circulatory effects of 0.5% timolol maleate eye drops on rabbit DCM models. Rabbits were randomly divided into healthy (n = 8) and DCM rabbits (n = 8). Rabbit DCM models were established through intravenous administration of daunorubicin (4 mg/kg/week), an anthracycline anticancer drug, for 6 weeks. We measured the HR, mean arterial pressure (MAP), and echocardiography before (pre) and at 10, 30, 60, and 120 minutes after timolol maleate administration. Timolol maleate 0.5% eye drops significantly reduced the HR at 10, 30, and 60 minutes in DCM models and 10 minutes in healthy rabbits; however, there were no alterations in MAP. There was a significant fraction shortening elevation at 10 and 120 minutes in DCM models; moreover, there were marked ejection fraction elevations at all measurement points in only DCM models. Timolol maleate eye drops exert several effects on the circulatory system in rabbit DCM models and healthy rabbits.

Citation

Mitsuhiro Isaka, Reimi Hayashida, Yuumi Tamashima, Ryuji Araki. Effects of timolol maleate eye drops on experimentally dilated cardiomyopathy and healthy rabbits. Open veterinary journal. 2021 Jul-Sep;11(3):390-393