大鼠压力超负荷性心肌肥大与三七总皂甙的干预效果药物剂量依赖效应

背景心肌肥大是以心肌细胞体积增加和蛋白质含量增多为主要特征的生长异常,防治心肌肥大的药物中,一些化学合成钙拮抗剂疗效较好,而中药二七的活性成分中也具有钙离子拮抗作用.目的观察三七总皂甙对腹主动脉缩窄大鼠心肌肥大的影响.设计完全随机分组设计,对照实验.单位广西医科大学药理学教研室.材料实验于2001-11/2003-02在广西医科大学实验中心药理实验室完成.选用25只健康雄性清洁级SD大鼠.将大鼠随机分为5组假手术对照组,腹主动脉缩窄组,三七总皂甙低、中、高剂量组,每组5只.方法腹主动脉缩窄组,三七总皂甙低、中、高剂量组均做腹主动脉缩窄手术(麻醉大鼠,在左肾动脉与腹主动脉汇合处上方分离一小段腹主动脉,穿过一条丝线,将直径0.6 mm针头平行于腹主动脉一并结扎,抽出针头,造成腹主动脉的缩窄)以建立压力超负荷性心肌肥大模型.假手术组除不作缩窄外,其余操作相同.假手术对照组和腹主动脉缩窄组在手术当天及术后每日腹腔注射生理盐水1 mL/kg,三七总皂甙低、中、高剂量组在手术当天及术后每日腹腔注射1 mL/kg三七总皂甙的生理盐水溶液,剂量分别为50,100和150 mg/(kg·d),持续3周.给大鼠做腹主动脉缩窄术3周后,称其体质量,左心质量,计算全心质量/体质量、左心室质量/体质量即左室质量指数.用光学显微镜和DMR+Q550病理图像分析仪观察切片,每张切片随机选取5个视野,测30个心肌细胞的直径,取平均值.组间差异比较采用单因素方差分析和q检验.主要观察指标行腹主动脉缩窄术3周后,各组大鼠全心质量、左心室质量、全心质量/体质量、左心室质量指数,心肌细胞直径比较.结果大鼠25只均进入结果分析.①光学显微镜下观察三七总皂甙对大鼠心肌细胞直径的影响与假手术对照组相比,腹主动脉缩窄组大鼠的心肌细胞发生肥大变化,心肌细胞直径变大;三七总皂甙低剂量组细胞与腹主动脉缩窄组相似;三七总皂甙中剂量组的细胞肥大在一定程度上逆转,但仍比假手术对照组细胞直径大、染色略深;三七总皂甙高剂量组细胞大小、颜色均接近假手术对照组,胞浆染色较三七总皂甙中剂量组更浅,细胞无明显肥大反应.②全心质量/体质量、左室质量指数腹主动脉缩窄组明显大于假手术对照组和三七总皂甙高剂量组(P＜0.01).全心质量/体质量、左室质量指数三七总皂甙低、中剂量组与腹主动脉缩窄组接近(P＞0.05).③心肌细胞直径二七总皂甙中剂量和高剂量组明显小于腹主动脉缩窄组(P＜0.05,0.01).结论剂量为100～150 mg/(kg·d)的三七总皂甙能抑制腹主动脉缩窄大鼠心肌肥大的形成,且剂量越大,抑制作用越明显.

Inhibitory effects of total saponins of panax notoginseng on cardiac hypertrophy induced by pressure overload in rats: dependent effect of medical dosage

BACKGROUND: The increase in cardiomyocyte size, and the enhancement of protein synthesis function are the main two defining features of cardiomyocyte hypertrophy. Calcium antagonists synthesized by chemical methods have already showed good effect in clinical treatment of cardiac hypertrophy. Total saponins of panax notoginseng (PNS) can also antagonize calcium channel on cell membrane.OBJECTIVE: To study the effect of PNS on cardiac hypertrophy of abdominal aorta-constricted rats.DESIGN: A completely randomized controlled study.SETTING: Pharmacological Lab of the Experimental Center of Guangxi Medical University.MATERIALS: The experiment was carried out at the Pharmacological Lab of the Experimental Center of Guangxi Medical University from November 2001 to February 2003. Twenty-five adult male SD rats were selected, and divided into five groups: including control group, aorta-constricted group, low, middle and high dose groups with five in each group.METHODS: Rats in abdominal-aorta coarctation group, low dose group,middle dose group and high dose group, were operated by constricting of abdominal aorta. The method was as followed: after anesthesia, 2 cm incision from ribs of left lumbar region was made, bluntly dissected subcutaneous fascia and muscle, exposed left kidney, separated a little part of abdominal aorta at the crossed area of left renal artery and abdominal aorta, threaded a line, deligated 0.6 mm parallel bullet and abdominal aorta, pulled out the bullet, formed abdominal arterial coarctation, dribbled ampulen into operative site to avoid infection, and sewed up muscle and skin by gradation. The rats in sham operation group were treated with the same ways except abdominal arterial coarctation. The rats in sham-operation control group and abdominal-aorta coarctation group were given 1 mL/kg saline (ip), and the rats in low, middle and high dose groups were given 1 mL/kg saline with PNS sured the body weight (BW), heart weight (HW), left ventricular weight (LVW), the ratio of HW/BW and LVW/BW (LVI). 3.0-4.0 mm tissue sheet was taken at the center of long axis in left ventricle. After fixed with neutral formaldehyde, slices were made into 3 μm and, dyed by HE color, then enlarged into 400 times. Slices were observed with light microscope and DMR-Q550 pathological image analyzer with 5 fields in each slice. Totally 30 cardiac myocyte diameters (MD) were measured to obtain the average value. The results were analyzed with one way analysis of variance (ANOVA) and q test.MAIN OUTCOME MEASURES: Heart-weight (HW), left ventricular weight (LVW), the ratio of HW/BW and LVW/BW (LVI), the cardiomyocyte diameters (MD).cal microscope, we found that left ventricular myocytes of hypertrophy group (group B) became larger than group A. On the transverse section of group B, the cardiac myocytes had elliptic or round shapes, and their karyons was a little bigger, their color was more saturate, their mean diameter (MD) became longer than control group (group A). On the slitting section of different groups, we also found that left ventricular myocytes of group B were the thickest ones amid the five groups. Cells of group C are similar to the ones of group B, hypertrophic reactions of these cells are obvious, but the middle and high dose groups (group D and group E) all and LVI in abdominal-aorta eoarctation group were significantly higher than that in sham-operation control group and high dose group (P ＜ 0.01).HW/BW and LVI in low and middle dose groups were close to that in abdomwas lower than that in abdominal-aorta coarctation group (P ＜ 0.05, 0.01).CONCLUTION: PNS can prevent cardiac hypertrophy by pressure overdosage is, the greater the inhibitory effect is.