2 to strengthen the pulse, increase blood pressure, and enhance heart sounds for chronic circulatory disorders accompanied by hypotension [6]. However, to the best of our knowledge, the therapeutic eﬀects of VAD on the heart failure have not been fully elucidated due to a lack of clinical and animal studies. Left coronary artery ligation is one of the widely used ani- mal models to mimic myocardial infarction and heart fail- ure in patients [7]. Echocardiography and serum brain na- triuretic peptide (BNP) levels are two commonly used in- dices to evaluate and diagnose heart failure [8]. To provide empirical evidence for VAD’s clinical application in the treat- ment of heart diseases, in the current study, we investigated its therapeutic eﬀects on heart failure following myocardial infarction with captopril as the positive control by evaluating echocardiographic parameters and serum BNP levels. 2. Methods and Materials 2.1. Animals and the Heart Failure Model. Male Wistar rats (N = 48, age 8 weeks, weighing 230 ± 20 g) were purchased from the Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences, Beijing, China. They were housed four/cage in a controlled environment (23 ± 1◦C; 45%–50% relative humidity; ﬁxed 12/12 h light/dark cycle, lights on at 08:00 h) with food and water ad libitum. All procedures were performed in accordance with the National Institute of Health’s Guide for the Use and Care of Laboratory Animals and were approved by the Committee on Animal Care and Use of the China-Japan Friendship Hospital. After seven-day acclimation, animals had their body weights measured at ﬁrst and then were anesthetized with intraperitoneal injection of 1% pentobarbital sodium. They were ﬁxed on their backs, intubated using a 16-gauge ca- theter, and artiﬁcially ventilated (80 stokes/min, 0.4 L/250 g) with a pressure-controlled respirator for small animals (RSP1002, Kent Scientiﬁc Corporation, CT, USA). An in- cision of the skin and intercostal muscles was made between the third and fourth ribs. Under the monitor of a lead 2 electrocardiogram (XJJ-11, Kent Scientiﬁc Corporation, CT, USA), a thoracotomy was performed and the pericardium was opened, which left the heart adequately exposed. To in- duce myocardial infarction, the left coronary artery was lig- ated 1.5–2 mm from the aortic root between the pulmonary cone and the left auricular appendage with silk sutures. Then the muscles and skins were sutured and the ventilation was stopped when rats’ heart rate and respiration went steady. The sham-operated animals underwent the same procedure except that the silk suture was placed around the left coronary artery without being tied. After the surgery, all animals were injected with penicillin for three days to prevent infection. Six rats with induced myocardial infarction died during the operation whereas two rats in the sham group died of infection. The operative mortality was 16.7%. 2.2. Drugs and Pharmacological Procedures. The powder of velvet antler of deer (VAD, The Scientiﬁc and Technological Development Center of Qingyuan Manchu Autonomous Evidence-Based Complementary and Alternative Medicine County, Liaoning Province, China) and captopril (CAP, Beijing Shuguang Pharmaceutical Co., Ltd., Beijing, China) were triturated and then well suspended in double-distilled water at the doses of 20 mg/mL and 1 mg/mL respectively. These doses were calculated according to the conversion table of animal doses to human equivalent doses based on body surface area [9]. Provided that the doses of rats should be seven times lower than those of humans, the clinical dose of VAD was 2 g/70 Kg and hence the equivalent dose for rats is 200 mg/Kg. Similarly, the clinical dose of captopril is 100 mg/70 Kg, and for rats the dose should be 10 mg/Kg. One week after the surgery, animals with myocardial infarction following left coronary artery ligation received daily treat- ment of double-distilled water (referred as the HF group), captopril (the HF + CAP group), or velvet (the HF + VAD group) by gavage (1 mL/100 mg body weight) for consecu- tively four weeks, while sham-operated animals (the SHAM group) were administered double-distilled water once daily for four weeks. 2.3. Measurement of Cardiac Structural and Functional Para- meters. Echocardiography (HDI 5000, Philips) was per- formed before rats were sacriﬁced. Under anesthesia by intraperitoneal injection of 40 mg/kg pentobarbital sodium, rats were ﬁxed on their backs with their fur shaved and skin cleaned. Using a high-frequency linear-array transducer (CL15-7), the structural parameters of the heart included left atrial diameter (LAD), left ventricular end-diastolic diam- eter (LVDd), left ventricular end-systolic diameter (LVDs), end-systolic interventricular septal thickness (IVSTs), end- diastolic interventricular septal thickness (IVSTd), left ven- tricular end-systolic posterior wall thickness (LVPWTs), and left ventricular end-diastolic posterior wall thickness (LVPWTd). Besides, two functional parameters were cal- culated by the following formulas: left ventricular short- axis fractional shortening (LVFS) = (LVDd-LVDs)/LVDd, left ventricular ejection fraction (LVEF) = (LVDd3- LVDs3)/ LVDd3. 2.4. Brain Natriuretic Peptide (BNP) Measurement. Blood samples were collected in EDTA tubes, which was then placed on ice and centrifuged within 30 min at 4◦C. The plasma was stored at −80◦C until assay. Radioimmunoassays for rat BNP were performed as previously reported [10]. Brieﬂy, stan- dards or samples were incubated with antibody for rat BNP for 24 hours at 4◦C. 125I-BNP (10 000 cpm) was then added, followed by additional incubation for 24 hours at 4◦C. Then after 90 min of incubation with a secondary antibody, free and bound fractions were separated, and the radioactivity of the bound fraction was measured by a gamma counter (EG&G Wallac, USA). 2.5. Statistical Analysis. All data were expressed as means ± standard deviation. Group diﬀerences were evaluated using one-way analysis of variance (ANOVA). If the variance of the data was heterogeneous, the Kruskal-Wallis test was adopted, which was followed by the Nemenyi multiple comparison test. P < 0.05 was considered to be statistically signiﬁcant.