Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan.
Open Vet J. 2021 Jul-Sep;11(3):390-393. doi: 10.5455/OVJ.2021.v11.i3.9. Epub 2021 Aug 5.
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 ( = 8) and DCM rabbits ( = 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.
扩张型心肌病（DCM）是兔子最常被诊断出的心肌病。马来酸噻吗洛尔（非选择性β受体阻滞剂）可降低心率（HR）和血压，已被用于治疗青光眼。然而，这种作用尚未在兔 DCM 模型中得到评估。
本研究旨在评估 0.5%马来酸噻吗洛尔滴眼液对兔 DCM 模型的循环影响。
兔子被随机分为健康组（n=8）和 DCM 组（n=8）。通过静脉注射蒽环类抗癌药物柔红霉素（4mg/kg/周），建立兔 DCM 模型，共 6 周。在给予马来酸噻吗洛尔前（pre）和给药后 10、30、60 和 120 分钟，我们测量了 HR、平均动脉压（MAP）和超声心动图。
0.5%马来酸噻吗洛尔滴眼液显著降低了 DCM 模型中 HR 在 10、30 和 60 分钟以及健康兔中 10 分钟时的 HR；然而，MAP 没有变化。DCM 模型在 10 和 120 分钟时出现明显的缩短分数升高；此外，仅在 DCM 模型中所有测量点均出现明显的射血分数升高。
马来酸噻吗洛尔滴眼液对兔 DCM 模型和健康兔的循环系统有多种作用。
