MLCK/p-MLC2 Signaling Pathway In Intestinal Mucosal Barrier Damage In Rats With Acute Pancreatitis And Its Relationship With Antimicrobial Peptides

Objective: To observe MLCK/p-MLC2 pathway in intestinal barrier injury of acute pancreatitis(AP)rats,and to explore its relationship with antimicrobial peptides.Methods: 24 SD rats were divided into control group and AP group.5%Taurocholic acid was retrogradely injected into the pancreaticobiliary duct to establish a rat model of AP.In the AP group,the samples were collected at 6h、12 h and 24 h after modeling,respectively.The control group was sampled at 6h after modeling.ELISA was performed to detect the serum levels of amylase and lipase,HE staining was performed to observe the ileal pathology,RT-q PCR was performed to detect the expression levels of REG3γ、 α-defencin 5 and lysozyme.Western blot was performed to detect the expression levels of ZO-1、Claudin-1,MLCK、p-MLC2.Results: Compared with the control group,the ileal pathology score 、serum levels of amylase and lipase were increased(P <0.05);the expression levels of ZO-1 protein、Claudin-1 protein、REG3γ m RNA,α-defencin 5m RNA and lysozyme m RNA in ileum were decreased(P <0.05);the expression levels of MLCK 、 p-MLC2 protein were increased in the AP group(P<0.05).Compared with the 6 h AP group,the ileal pathology score、 serum levels of amylase and lipase were increased(P <0.05);the expression levels of ZO-1 protein、Claudin-1 protein、REG3γ m RNA,α-defencin 5 m RNA and lysozyme m RNA in ileum were decreased(P <0.05);the expression levels of MLCK、 p-MLC2 protein were increased in the 12 h and 24 h AP group(P<0.05).Compared with the 12 h AP group,the ileal pathology score、serum levels of amylase and lipase were increased(P <0.05);the expression levels of ZO-1 protein、Claudin-1 protein、REG3γ m RNA,α-defencin 5 m RNA and lysozyme m RNA in ileum were decreased(P <0.05);the expression levels of MLCK、p-MLC2 protein were increased in the 24 h AP group(P <0.05).The expression level of MLCK protein in the ileum of AP group was negatively correlated with the m RNA levels of REG3γ,α-defensin 5 and lysozyme(r =-0.96,-0.95 and-0.93,respectively,P <0.05).The expression level of P-MLC2 protein was also negatively correlated with the m RNA levels of REG3γ,α-defensin 5 and lysozyme(r =-0.96,-0.94 and-0.96,respectively,P <0.05).Conclusion: The activation of the MLCK/p-MLC2 pathway in AP rats may be involved in the damage of the AP intestinal barrier,which may be related to the decrease of the secretion of antimicrobial peptides by Pan’s cells.