To investigate the effects of carbachol on lipopolysaccharide (LPS)-induced intestinal barrier breakdown.

C57BL/6 mice were randomly divided into four groups (n=10 per group): control group, lipopolysaccharide group, carbachol group, and α-bungarotoxin group. Endotoxemia was induced by administering 10 mg/kg lipopolysaccharide via intraperitoneal injection. The mice were intraperitoneally treated with 0.1 mg/kg carbachol 15 min after LPS administration. Mice were sacrificed at 3 h after LPS administration for biochemical studies and histological examination. The localization and expression of Claudin-2 and myosin light chain kinase (MLCK), and pathologic changes of the ileum were examined.

The levels of FITC-glucan in the control group, endotoxemia group, carbachol group, and α bungarotoxin group were (2.33±0.51) μg/ml, (55.25±5.41) μg/ml, (19.27±3.53) μg/ml, and (48.45 ±9.50) μg, respectively; there was a significant difference among the four groups (F=111.8, P<0.05), as well as between the endotoxemia group and control group, between the endotoxemia group and carbachol group, and between the α bungarotoxin group and carbachol group (t=22.52, 15.31, and 12.42, P<0.05). The contents of Claudin-2 protein in the control group, endotoxemia group, carbachol group, and α bungarotoxin group were (0.82±0.08) μg/ml, (0.52±0.09) μg/ml, (0.77±0.05) μg/ml, and (0.53±0.09) μg, respectively; there was a significant difference among the four groups (F=11.61, P<0.05), as well as between the endotoxemia group and control group, between the endotoxemia group and carbachol group, and between the α bungarotoxin group and carbachol group (t=6.518, 5.366, and 5.167, respectively, P<0.05). The contents of MLCK protein in the control group, endotoxemia group, carbachol group, and α bungarotoxin group were (0.58±0.07) μg/ml, (1.07±0.17) μg/ml, (0.69±0.11) μg/ml, and (0.94 ±0.05) μg, respectively; there was a significant difference among the four groups (F=12.64, P<0.05), as well as between the endotoxemia group and control group, between the endotoxemia group and carbachol group, and between the α bungarotoxin group and carbachol group (t=7.79, 5.881, and 3.892, respectively, P<0.05).

Carbachol treatment can protect against LPS-induced intestinal barrier dysfunction and the protective effects are associated with the activation of the cholinergic anti-inflammatory pathway.