ABC | Volume 110, Nº6, June 2018

Original Article Pressure Overload-induced Cardiac Hypertrophy Varies According to Different Ligation Needle Sizes and Body Weights in Mice Zhen Jia, 1 Zhijun Chen, 2 Hongfei Xu, 1 Malik Akuffu Armah, 1 Peng Teng, 1 Weidong Li, 1 Dongdong Jian, 1 Liang Ma, 1 Yiming Ni 1 Department of Cardio-Thoracic Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, 1 Zhejiang - China Department of Cardio-Thoracic Surgery, Zhoushan Hospital, 2 Zhejiang - China Mailing Address: Yiming Ni • Department of Cardio-Thoracic Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003 – China E-mail: 1183020@zju.edu.cn Manuscript received August 21, 2017, revised manuscript October 25, 2017, accepted November 24, 2017 DOI: 10.5935/abc.20180088 Abstract Background: The cardiac hypertrophy (CH) model for mice has been widely used, thereby providing an effective research foundation for CH exploration. Objective: To research the effects of CH modeling under abdominal aortic constriction (AAC) using different needles and weights in mice. Methods: Four needles with different external diameters (0.35, 0.40, 0.45, and 0.50 mm) were used for AAC. 150 male C57BL/6 mice were selected according to body weight (BW) and divided into 3 weight levels: 18 g, 22 g, and 26 g (n = 50 in each group). All weight levels were divided into 5 groups: a sham group (n = 10) and 4 AAC groups using 4 ligation intensities (n = 10 per group). After surgery, survival rates were recorded, echocardiography was performed, hearts were dissected and used for histological detection, and data were statistically analyzed, P < 0.05 was considered statistically significant. Results: All mice died in the following AAC groups: 18g/0.35 mm, 22 g/0.35 mm, 26 g/0.35 mm, 22 g/0.40 mm, and 26 g/0.40 mm. All mice with AAC, those ligated with a 0.50-mm needle, and those that underwent sham operation survived. Different death rates occurred in the following AAC groups: 18 g/0.40 mm, 18 g/0.45 mm, 18 g/0.50 mm, 22 g/45 mm, 22 g/0.50 mm, 26 g/0.45 mm, and 26 g/0.50 mm. The heart weight/body weight ratios (5.39 ± 0.85, 6.41 ± 0.68, 4.67 ± 0.37, 5.22 ± 0.42, 4.23 ± 0.28, 5.41 ± 0.14, and 4.02 ± 0.13) were significantly increased compared with those of the sham groups for mice with the same weight levels. Conclusion: A 0.45-mmneedle led tomore obvious CH than did 0.40-mm and 0.50-mmneedles and caused extraordinary CH in 18-g mice. (Arq Bras Cardiol. 2018; 110(6):568-576) Keywords: Cardiomegaly; Body Weight; Heart Failure; Needles/utilization; Rats. Introduction Cardiac hypertrophy (CH) is a compensatory pathological change that is usually induced by pressure overload (PO), neurohumoral abnormality, and the effects of cytokines. It is characterized by cardiomyocyte hypertrophy and interstitial hyperplasia, and it results in an enlarged heart and thickening of the heart walls. Clinically, CH is involved in the development of many diseases, such as valvular disease, hypertension, arterial stenosis, and primary myocardial hypertrophy. If these diseases develop at their own pace, then cardiac function (CF) will gradually decompensate, leading to heart failure (HF), which severely lowers the quality of life and increases the mortality rate. Therefore, CH is a widespread concern and has been explored at the molecular level by researchers. Due to the high genomic homology between mice and humans, an established CH model for mice has been widely used in animal experiments, thereby providing an effective research foundation for CH exploration. Currently, PO-induced CH is a common way to establish the model. Abdominal aortic constriction (AAC) is highly recommended by researchers because of the high success rate and the ability to perform surgery without the need for thoracotomy or a ventilator. However, the modeling effects with different ligating intensities for certain body weights (BWs) have not yet been reported. Therefore, we used 3 frequently used mice BWs (18 g, 22 g, and 26 g) and 4 different needle sizes (0.35, 0.40, 0.45, and 0.50 mm) to establish the CH model for each weight level for AAC, summarized the survival rates, and evaluated the CH effects. 568