Corrigendum to "Propofol Attenuates Small Intestinal Ischemia Reperfusion Injury through Inhibiting NADPH Oxidase Mediated Mast Cell Activation".

[This corrects the article DOI: 10.1155/2015/167014.].

Propofol attenuated liver transplantation-induced acute lung injury via connexin43 gap junction inhibition.

BACKGROUND: Postoperative acute lung injury (ALI) is a severe complication after liver transplantation, which influences patient survival rate obviously. However, its mechanisms are unclear and effective therapies are still lacking. The current study focused on effects of propofol on liver transplantation-induced ALI and whether its underlying mechanism was relative with connexin43 (Cx43) alternation. The authors postulated that endotoxin induced enhancement of Cx43 gap junction (GJ) plays a critical role in mediating post liver transplantation ALI and that pretreatment with the anesthetic propofol, known to inhibit gap junction, can confer effective protection. METHODS: Male Sprague-Dawley rats underwent autologous orthotopic liver transplantation (AOLT) in the absence or presence of treatments with the selective Cx43 inhibitor, enanthol (0.1 mg/kg) and propofol (50 mg/kg), a commonly used anesthetic in clinical anesthesia. In vitro study, BEAS-2B cells, a kind of lung epithelial cell line expressing Cx43, exposed to lipopolysaccharide (LPS), which mainly contributed to ALI. Function of Cx43 GJ was regulated by Cx43 specific inhibitors, gap26 (300 µM) or enhancer, retinoic acid (10 µM) and two specific siRNAs. RESULTS: Compared with the sham group, AOLT results in ALI obviously with plasma endotoxin increase. Cx43 inhibition decreased ALI through inflammatory reaction reduction. In vitro studies, LPS-induced BEAS-2B cells damage was attenuated by Cx43 function inhibition, but amplified by enhancement. Another important finding was propofol reduced Cx43 function and protected against LPS-mediated BEAS-2B cells damage or AOLT-induced ALI, mechanisms of which were also associated with inflammatory reaction decrease. CONCLUSION: Cx43 plays a vital role in liver transplantation-induced ALI. Propofol decreased Cx43 function and protected against ALI in vivo and in vitro. This finding provide a new basis for targeted intervention of organ protection in liver transplantation, even in other kinds of operations.

Propofol Attenuates Small Intestinal Ischemia Reperfusion Injury through Inhibiting NADPH Oxidase Mediated Mast Cell Activation.

Both oxidative stress and mast cell (MC) degranulation participate in the process of small intestinal ischemia reperfusion (IIR) injury, and oxidative stress induces MC degranulation. Propofol, an anesthetic with antioxidant property, can attenuate IIR injury. We postulated that propofol can protect against IIR injury by inhibiting oxidative stress subsequent from NADPH oxidase mediated MC activation. Cultured RBL-2H3 cells were pretreated with antioxidant N-acetylcysteine (NAC) or propofol and subjected to hydrogen peroxide (H2O2) stimulation without or with MC degranulator compound 48/80 (CP). H2O2 significantly increased cells degranulation, which was abolished by NAC or propofol. MC degranulation by CP further aggravated H2O2 induced cell degranulation of small intestinal epithelial cell, IEC-6 cells, stimulated by tryptase. Rats subjected to IIR showed significant increases in cellular injury and elevations of NADPH oxidase subunits p47(phox) and gp91(phox) protein expression, increases of the specific lipid peroxidation product 15-F2t-Isoprostane and interleukin-6, and reductions in superoxide dismutase activity with concomitant enhancements in tryptase and ß-hexosaminidase. MC degranulation by CP further aggravated IIR injury. And all these changes were attenuated by NAC or propofol pretreatment, which also abrogated CP-mediated exacerbation of IIR injury. It is concluded that pretreatment of propofol confers protection against IIR injury by suppressing NADPH oxidase mediated MC activation.

Sevoflurane ameliorates intestinal ischemia-reperfusion-induced lung injury by inhibiting the synergistic action between mast cell activation and oxidative stress.

Preconditioning with sevoflurane (SEV) can protect against ischemia-reperfusion injury in several organs, however, the benefits of SEV against acute lung injury (ALI), induced by intestinal ischemia-reperfusion (IIR), and the underlying mechanisms remain to be elucidated. The present study was designed to investigate the effects of SEV preconditioning on IIR-mediated ALI and the associated mechanisms in a rat model. Female Sprague-Dawley rats treated with 2.3% SEV or apocynin (AP), an inhibitor of NADPH oxidase, were subjected to 75 min superior mesenteric artery occlusion followed by 2 h reperfusion in the presence or absence of the mast cell degranulator compound 48/80 (CP). SEV and AP were observed to downregulate the protein expression levels of p47(phox) and gp91(phox) in the lungs of normal rats. IIR resulted in severe lung injury, characterized by significant increases in pathological injury scores, lung wet/dry weight ratio, protein expression levels of p4(7phox), gp91(phox) and ICAM-1, the presence of hydrogen peroxide, malondydehyde and interleukin-6, and the activity of myeloperoxidase. In addition, significant reductions were observed in the expression of prosurfactant protein C, accompanied by an increase in MC degranulation, demonstrated by significant elevations in the number of mast cells, expression levels of tryptase and the concentration of ß-hexosaminidase. These changes were further augmented in the presence of CP. In addition, SEV and AP preconditioning significantly alleviated the above alterations induced by IIR alone or in combination with CP. These findings suggested that SEV and AP attenuated IIR-induced ALI by inhibiting NADPH oxidase and the synergistic action between oxidative stress and mast cell activation.

Propofol prevents lung injury after intestinal ischemia-reperfusion by inhibiting the interaction between mast cell activation and oxidative stress.

AIMS: Both mast cells and oxidative stress are involved in acute lung injury (ALI) induced by intestinal ischemia-reperfusion (IIR). The aim of this study was to investigate whether propofol could improve IIR-induced ALI through inhibiting their interaction. MAIN METHODS: Repetitive, brief IIR or IIR+compound 48/80 was performed in adult Sprague-Dawley rats pretreated with saline, apocynin or propofol. And their lungs were excised for histology, ELISA and protein-expression measurements 2h after reperfusion. KEY FINDINGS: Rats pretreated with saline developed critical ALI 2h after IIR. We found significant elevations in lung injury scores, lung wet/dry ratio and gp91phox, p47phox, intercellular cell adhesion molecule-1 protein expressions and higher level of malondialdehyde, interleukin-6 contents, and myeloperoxidase activities, as well as significant reductions in superoxide dismutase activities, accompanied with increases in mast cell degranulation evidenced by significant increases in mast cell counts, ß-hexosaminidase concentrations, and tryptase expression. And the lung injury was aggravated in the presence of compound 48/80. However, pretreated with propofol and apocynin not only ameliorated the IIR-mediated pulmonary changes beyond the biochemical changes but also reversed the changes that were aggravated by compound 48/80. SIGNIFICANCE: Propofol protects against IIR-mediated ALI, most likely by inhibiting the interaction between oxidative stress and mast cell degranulation.

The interaction between oxidative stress and mast cell activation plays a role in acute lung injuries induced by intestinal ischemia-reperfusion.

BACKGROUND: Both oxidative stress and mast cells are involved in acute lung injuries (ALIs) that are induced by intestinal ischemia-reperfusion (IIR). The aim of this study was to further investigate the interaction between oxidative stress and mast cells during the process of IIR-induced ALI. MATERIALS AND METHODS: Thirty adult Sprague-Dawley rats were randomly divided into five groups: sham, IIR, IIR + compound 48/80 (CP), N-acetylcysteine (NAC) + IIR, and NAC + IIR + CP. All rats except those in the sham group were subjected to 75 min of superior mesenteric artery occlusion, followed by 2 h of reperfusion. The rats in the NAC + IIR and NAC + IIR + CP groups were injected intraperitoneally with NAC (0.5 g/kg) for three successive days before undergoing IIR. The rats in the IIR + CP and NAC + IIR + CP groups were treated with CP (0.75 mg/kg), which was administered intravenously 5 min before the reperfusion. At the end of the experiment, lung tissue was obtained for pathologic and biochemical assays. RESULTS: IIR resulted in ALI, which was detected by elevated pathology scores, a higher lung wet-to-dry ratio, and decreased expression of prosurfactant protein C (P < 0.05). Concomitant elevations were observed in the expression levels of the nicotinamide adenine dinucleotide phosphate oxidase subunits p47(phox) and gp91(phox) and the levels of hydrogen peroxide and malondialdehyde. However, superoxide dismutase activity in the lung was reduced (P < 0.05). The level of interleukin 6, the activity of myeloperoxidase, and the expression of intercellular adhesion molecule 1 were also increased in the lung. IIR led to pulmonary mast cell degranulation and increases in the plasma and pulmonary ß-hexosaminidase levels, mast cell counts, and tryptase expression in lung tissue. CP aggravated these conditions, altering the measurements further, whereas NAC attenuated the IIR-induced ALI and all biochemical changes (P < 0.05). However, CP abolished some of the protective effects of NAC. CONCLUSIONS: Oxidative stress and mast cells interact with each other and promote IIR-induced ALI.

The mechanism of sevoflurane preconditioning-induced protections against small intestinal ischemia reperfusion injury is independent of mast cell in rats.

The study aimed to investigate whether sevoflurane preconditioning can protect against small intestinal ischemia reperfusion (IIR) injury and to explore whether mast cell (MC) is involved in the protections provided by sevoflurane preconditioning. Sprague-Dawley rats exposed to sevoflurane or treated with MC stabilizer cromolyn sodium (CS) were subjected to 75-minute superior mesenteric artery occlusion followed by 2-hour reperfusion in the presence or absence of MC degranulator compound 48/80 (CP). Small intestinal ischemia reperfusion resulted in severe intestinal injury as demonstrated by significant elevations in intestinal injury scores and p47(phox) and gp91(phox), ICAM-1 protein expressions and malondialdehyde and IL-6 contents, and MPO activities as well as significant reductions in SOD activities, accompanied with concomitant increases in mast cell degranulation evidenced by significant increases in MC counts, tryptase expression, and ß-hexosaminidase concentrations, and those alterations were further upregulated in the presence of CP. Sevoflurane preconditioning dramatically attenuated the previous IIR-induced alterations except MC counts, tryptase, and ß-hexosaminidase which were significantly reduced by CS treatment. Furthermore, CP exacerbated IIR injury was abrogated by CS but not by sevoflurane preconditioning. The data collectively indicate that sevoflurane preconditioning confers protections against IIR injury, and MC is not involved in the protective process.

Dual Effects of Bilirubin on the Proliferation of Rat Renal NRK52E Cells and ITS Association with Gap Junctions.

OBJECTIVE: The effect of bilirubin on renal pathophysiology is controversial. This study aimed to observe the effects of bilirubin on the proliferation of normal rat renal tubular epithelial cell line (NRK52E) and its potential interplay with gap junction function. METHODS: Cultured NRK52E cells, seeded respectively at high- or low- densities, were treated with varying concentrations of bilirubin for 24 hours. Cell injury was assessed by measuring cell viability and proliferation, and gap junction function was assessed by Parachute dye-coupling assay. Connexin 43 protein was assessed by Western blotting. RESULTS: At doses from 17.1 to 513µmol/L, bilirubin dose-dependently enhanced cell viability and colony-formation rates when cells were seeded at either high- or low- densities (all p<0.05 vs. solvent group) accompanied with enhanced intercellular fluorescence transmission and increased Cx43 protein expression in high-density cells. However, the above effects of BR were gradually reversed when its concentration increased from 684 to 1026µmol/L. In high-density cells, gap junction inhibitor 12-O-tetradecanoylphorbol 13-acetate attenuated bilirubin-induced enhancement of colony-formation and fluorescence transmission. However, in the presence of high concentration bilirubin (1026µmol/L), activation of gap junction with retinoid acid decreased colony-formation rates. CONCLUSION: Bilirubin can confer biphasic effects on renal NRK52E cell proliferation potentially by differentially affecting gap junction functions.