TM-1在壓力過載ICR小鼠模式之心臟保護效果的探討

Abstract

背景：TM-1是(+)-thaliporphine的衍生物。在之前本實驗室研究發現到長期口服 20mg/kg TM-1會減少小鼠心肌缺血再灌流時心肌細胞的壞死。然而，心肌因為缺氧壞死的情形亦發生在壓力過載引起心臟肥大的過程中。本篇主要研究長期口服 20mg/kg TM-1在壓力過載的ICR小鼠是否具有心臟的保護效果以及探討可能的機轉。 方法：以腹部主動脈結紮建立壓力過載ICR小鼠模式，將手術後的老鼠分別口服給予2個月的vehicle和20mg/kg TM-1來觀察其對心臟構造上和功能上的保護作用。採血測量小鼠血清中agiotensin II、ANP和LDH的含量。利用西方點墨法去看小鼠心臟組織中α-SMA、p-ERK、p-Akt和p-GSK3β表現量的變化。利用組織切片HE染色來定量心肌細胞直徑大小以及MT染色來看心肌細胞中collagen的含量。另外，以pilocarpine引發癲癇小鼠模式來看口服給予20mg/kg TM-1對於癲癇小鼠的安全性。 結果：本實驗發現長期口服給予20mg/kg TM-1可以有效抑制壓力過載造成的心臟肥大以及左心室功能的下降，並抑制血清中angiotensin II、ANP和LDH釋放量。此外，長期口服20mg/kg TM-1也會抑制心臟組織中α-SMA、p-ERK、p-Akt和p-GSK3β表現量的上升。從組織切片MT染色觀察到長期口服20mg/kg TM-1可以減少心臟纖維化的情形。另外，口服pretreat 20mg/kg TM-1對於pilocarpine引起癲癇小鼠其大、小發作頻率和死亡率皆無明顯影響。

結論：長期口服20mg/kg TM-1可以有效抑制心臟細胞的肥大和防止心臟功能變差，其可能的機轉是TM-1抑制心臟組織中ERK、Akt和GSK3β的活化來達到對於心臟的保護作用。

Background: TM-1 is a molecular derivative of thaliporpine. Our previous studies have shown that chronic oral treatment with 20mg/kg TM-1 had cardioprotective effects on myocardial ischemia-reperfusion injury. However, myocardial cell necrosis induced by hypoxia or ischemia also occurs in pressure overload-induced hypertrophy. The aim of this study was to investigate cardioprotective effects of chronic treatment with TM-1 in pressure-overload ICR mice model. Method: Abdominal aortic banding was performed in ICR mice. Operated mice were randomly classified to treatment with vehicle or 20mg/kg TM-1 for 2 months. Morphologic and hemodynamic measurements were done after 2 months drug treatment to check the cardioprotective effects, and we also evaluated their plasma angiotensin II, ANP and LDH level. According to western blot analysis, we observed the changes of α-SMA, p-ERK, p-Akt and p-GSK3β expression in cardiac myocytes. Use HE staining method to observe diameter of cadiomyocytes and MT staining method to observe collagen accumulation. Besides, we check the severity of pilocarpine-induced epilepsy in mice combined with oral pretreatment of 20mg/kg TM-1. Results: Our results showed that chronic oral treatment with 20mg/kg TM-1 inhibited cardiac hypertrophy and improved cardiac function induced by pressure overload. TM-1 also inhibited the release of angiotensin II, ANP and LDH. Besides, pressure overload-induced activaton ofα-SMA, ERK, Akt and GSK-3β was significantly reduced by chronic oral treatment with 20mg/kg TM-1. We also found that chronic oral treatment with 20mg/kg TM-1 reduced cardiac collagen accumulation. On the other hand, oral treatment with 20mg/kg TM-1 had no effects on seizure frequency, epilepsy frequency and mortality rate induced by pilocarpine in mice. Conclusion: Chronic oral treatment with 20mg/kg TM-1 inhibited cardiac hypertrophy and improved cardiac function of AAB mice. This cardioprotective effects of TM-1 was related to its inhibitions of ERK, Akt and GSK-3β.