The protective role of montelukast against intestinal ischemia-reperfusion injury in rats

Abstract

Several drugs are effective in attenuating intestinal ischemia-reperfusion injury (IRI); however little is known about the effect of montelukast. Fifty rats were randomly assigned to 3 groups: model group (operation with clamping), sham group (operation without clamping), and study group (operation with clamping and 0.2, 2 and 20 mg/kg montelukast pretreatment). Intestinal ischemia-reperfusion was performed by occlusion (clamping) of the arteria mesenterica anterior for 45 min, followed by 24 h reperfusion. Intestinal IRI in the model group led to severe damage of the intestinal mucosa, liver and kidney. The Chiu scores of the intestines from the study group (2 and 20 mg/kg) were lower than that of the model group. Intestinal IRI induced a marked increase in CysLTR1, Caspase-8 and -9 expression in intestine, liver and kidney, which were markedly reduced by preconditioning with 2 mg/kg montelukast. Preconditioning with 2 g/kg montelukast significantly attenuated hepatic tissue injury and kidney damage, and decreased plasma interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels in plasma after intestinal IRI. In conclusion, preconditioning with montelukast could attenuate intestinal IRI and the subsequent systemic inflammatory response in rats.

Figure 1. Montelukast protects against intestinal injury after intestinal ischemia-reperfusion injury (IRI).

Representative photomicrographs (100×) of sham-operated group (A), model group (B), and study group with 0.2 mg/kg (C), 2 mg/kg (D), 20 mg/kg (E) montelukast. Black arrow denotes areas of bleeding and necrosis, red arrow denotes areas of neutrophil infiltration. Intestinal histology was evaluated using the Chiu score ((F); scale 0–5). *P < 0.05.

Figure 2. Cysteinyl leukotrienes receptor-1(CysLTR1) protein and mRNA expression after intestinal IRI.

CysLTR1 protein expression was detected by western blotting (a,b) and mRNA expression by real-time PCR (c). *P < 0.05.

Figure 3. Montelukast protects against apoptosis after intestinal IRI.

Representative photomicrographs illustrating apoptotic nuclei (TUNEL fluorescence staining) in the intestine of the sham group (A), model group (B), and study group ((C), montelukast, 2 mg/kg) (representative of four experiments, 100× magnifications). (D) Histogram of the AI in the ileum of rats. *P < 0.05. Rats after intestinal IRI showed many TUNEL-positive cells in the distal tips of villi in the small intestine (Fig. 3B, arrow denotes TUNEL-positive cell).

Figure 4. Caspase-8 and caspase-9 protein expression after intestinal IRI.

Protein expression was detected by western blotting. *P < 0.05.

Figure 5. Montelukast reduces liver injury after intestinal IRI.

Representative photomicrographs of livers from rats in different treatment groups ((A); H&E staining, 200× magnification. A-a, sham group; A-b, control group; A-c, study group). Arrows indicate vacuolisation. CysLTR1, caspase-8 and caspase-9 protein expression in liver from different groups. Plasma ALT and AST levels were measured in rats at various times after intestinal IRI (C).

Figure 6. Montelukast reduces kidney injury after intestinal IRI.

Representative photomicrographs of kidneys from rats in different groups (A-a, sham group; A-b, control group; A-c, study group. H&E, 200× magnification). highlighting tubular simplification, hypereosinophilia and glomerular atrophy (A-b, down and red arrows). Expression of NGAL in renal tissues in different treatment groups ((B), B-a, sham group; B-b, control group; B-c, study group). CysLTR1 protein expression in the kidney from different treatment groups by immunohistochemistry and western blotting ((C,D). C-a, sham group; C-b, control group; C-c, study group). Protein expression of caspase-8 and caspase-9 in the kidney (E,F). *P < 0.05.

Figure 7. Plasma interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels after intestinal IRI in rats.

Blood was obtained immediately after serum creatinine reperfusion, and IL-6 and TNF-α levels were assessed by ELISA. *P < 0.05.