Stellate Ganglion Blockade repairs Intestinal Mucosal Barrier through suppression of Endoplasmic Reticulum Stress following Hemorrhagic Shock

Abstract

Background: Hemorrhagic shock-induced ischemia and hypoxia elicit endoplasmic reticulum stress (ERS) that leads to cell apoptosis, tissue structural damage and organ dysfunction and failure. Stellate ganglion blockade (SGB) has been demonstrated to improve intestinal barrier dysfunction induced by hemorrhagic shock. The present study sought to investigate whether the beneficial effect of SGB on the intestinal mucosal barrier function is via suppression of ERS. Materials and methods: A conscious rat model of hemorrhagic shock (40 ±2 mmHg for 1 hour, followed by resuscitation) was established. The parameters reflecting intestinal morphology and intestinal mucosal barrier function including wet-dry ratio (W/D), intestinal permeability, D-lactic acid (D-LA) and intestinal fatty acid binding protein (I-FABP) in plasma, and expressions of ATF6α, PERK, and IRE1α in intestinal tissues were then observed. Furthermore, the effects of either SGB or ERS inhibitor, 4-phenylbutyric acid (4-PBA), on these parameters in rats with hemorrhagic shock were assessed. The effect of ERS agonist tunicamycin (TM) on the rats subjected with both SGB and hemorrhagic shock was also determined. Results: Either SGB or administration of ERS inhibitor, 4-PBA, alleviated hemorrhagic shock-induced adverse effects such as intestinal mucosal barrier dysfunction and excessive autophagy, which were characterized by damaged intestinal tissue, enhanced intestinal permeability and D-LA and I-FABP levels in plasma, and increased expressions of ATF6α, PERK, IRE1α in intestinal tissue. In contrast, administration of ERS agonist, TM, suppressed the beneficial effects of SGB on intestinal tissue and function during hemorrhagic shock. Conclusion: The SGB repairs intestinal mucosal barrier through suppression of ERS following hemorrhagic shock.

Keywords: Endoplasmic reticulum stress; Hemorrhagic shock; Intestinal mucosal barrier; Stellate ganglion blockade.

Figure 1

Changes of MAP in rats after hemorrhagic shock. Data are presented as mean ± SEM, with n = 4-6 for each group. *P < 0.05 vs. the Sham group at the same time.

Figure 2

Role of ERS in SGB alleviating hemorrhagic shock induced-intestinal injury in rats. (A) Characteristic images of intestinal histopathology (HE staining, Bar = 100 µm); (B) Height of intestinal villus; (C) Submucosal thickness; (D) Muscularis thickness; (E) Wet/dry ratio (W/D) of intestines. Data are presented as mean ± SEM, with n = 3 for each group. The analysis of ANOVA showed that there was statistical difference among these six groups, followed by LSD test as follows: *P < 0.05 vs. the Sham group, ^#P < 0.05 vs. the Shock group, ^ΔP < 0.05 vs. the Shock+SGB group.

Figure 3

Role of ERS in SGB alleviating hemorrhagic shock induced-intestinal barrier dysfunction in rats. (A-B) Levels of D-lactic acid (D-LA) and intestinal fatty acid binding protein (I-FABP) in plasma; (C) Intestinal clearance of fluorescein isothiocyanate-dextran (FD4) in rats. Data are presented as mean ± SEM, with n = 6 for each group. The analysis of ANOVA showed that there was statistical difference among these six groups, followed by LSD test as follows: * P < 0.05 vs. the Sham group, ^#P < 0.05 vs. the Shock group, ^ΔP < 0.05 vs. the Shock+SGB group.

Figure 4

SGB reduced expressions of ATF6α, PERK and IRE1α in intestinal tissue in rats after hemorrhagic shock. Data are presented as mean ± SEM, with n = 3 for each group. The analysis of ANOVA showed that there was statistical difference among these six groups, followed by LSD test as follows: *P < 0.05 vs. the Sham group, ^#P < 0.05 vs. the Shock group, ^ΔP < 0.05 vs. the Shock+SGB group.