Expression of MYPT1, CPI-17 and MLC20 in ileum of neonatal mouse NEC model and its significance

The present study determined the changes in the expression levels of MYPT1, CPI-17 and MLC20 in the ileum of mice with neonatal induced necrotizing enterocolitis (NEC) to provide a basis for a pathogenesis model that includes smooth muscle changes during NEC. A group of 7-day-old BALB/c mice were fed with formula (40 µl/g, 5 times/day) and given hypoxia treatments (5% O2 and 95% N2 for 10 min, twice daily) for 4 days to induce NEC and establish a mouse model. A control group of 7-day-old BALB/c mice were left with their mother for the duration of the treatment. After establishing the model, the two groups of mice were sacrificed, and the terminal ileum tissue was collected and subjected to western blot analysis and immunohistochemistry. The results showed the expression levels of MYPT1 and pMYPT1 in the ileum of the mice in the NEC group were lower than those in the control group (P<0.01). The levels of CPI17 and pCPI17 were higher in the NEC group compared with those in the control group. The expression level of MLC20 in NEC group was lower than that in the control group (P<0.01), but the level of pMLC20 in the NEC group was higher (P<0.05). The results of immunohistochemistry showed that the staining intensities of MYPT1, CPI-17 and MLC20 in the NEC group were lighter than those in the control group, and the proportion of positive cells was also lower in the NEC group (P<0.01). Taken together our results suggest that establishment of NEC is accompanied by changes in the protein levels of MYPT1 and pCPI-17, which can regulate smooth muscle contraction in the ileum.