Role of mesenteric lymph drainage in the balance of ACE/ACE2 in murine myocardium following hemorrhagic shock

Abstract

To observe the change of angiotensin converting enzyme (ACE) and ACE2 in the murine myocardium followed hemorrhagic shock and the role of post-hemorrhagic shock mesenteric lymph (PHSML) drainage. Twenty-four male mice were ran-domly divided into control, sham, shock, and shock + drainage groups. A hemorrhagic shock model was established and then fluid resuscita-tion was performed to the mice in the shock and shock + drainage groups, and the PHMSL was drained in the shock + drainage group after fluid resuscitation. After 6 h of resuscitation in the shock and shock + drainage groups or corresponding time in the sham group, or after anesthesia in the control group, the myocardial tissues were harvested for the determination of the mRNA expressions of ACE, ACE2, angiotensin Ⅱ (Ang Ⅱ) type 1 receptor (AT1R), and Mas related G protein coupled receptor (Mas1R) using the method of qRT-PCR, and the levels of Ang Ⅱ and Ang (1-7) using the method of ELISA. In the myocardial tissue of shock group, the ACE and AT1R mRNA expressions and Ang Ⅱ level were significantly increased than those of the control and sham groups, the ACE2 and Mas1R mRNA expressions were significantly de-creased than that of the control and sham groups, the Ang (1-7) level was decreased compared with the control group, the ratios of ACE/ACE2, Ang Ⅱ/Ang (1-7), and AT1R/Mas1R in the shock group were significantly increased than the control and sham groups. Meanwhile, PHSML drainage obviously suppressed the effects of hemorrhagic shock on these indices. Hemorrhagic shock up-regulated the ACE-Ang Ⅱ-AT1R axis, down-regulated the ACE2-Ang (1-7)-Mas1R axis, and induced the unbalance of ACE and ACE2 in myocardial tis-sue. PHSML drainage decreased the ACE-Ang Ⅱ-AT1R axis and increased the ACE2-Ang (1-7)-Mas1R axis, resulted in the balance of ACE and ACE2.