[mRNA expression of MDR3 gene in the blood of preterm infants with parenteral nutrition-associated cholestasis].

OBJECTIVE: To study the association between the expression of the MDR3 gene and the pathogenesis of parenteral nutrition-associated cholestasis (PNAC) in preterm infants. METHODS: Among the preterm infants who were admitted to the hospital from June 2011 to November 2017 and received parenteral nutrition for more than 14 days, 80 who did not develop PNAC were enrolled as non-PNAC group, and 76 who developed PNAC were enrolled as PNAC group. On days 1, 14, 30, 60 and 90 after birth, serum hepatobiliary biochemical parameters [alanine aminotransferase (ALT), total bilirubin (TBil), direct bilirubin (DBil), total bile acid (TBA) and gamma-glutamyl transpeptidase (γ-GT)], fibrosis indices [hyaluronic acid, laminin, procollagen III N-terminal peptide and type IV collagen] and clinical manifestations were observed. Real-time quantitative PCR was used to measure the mRNA expression of MDR3 in both groups, and the correlation between the mRNA expression of MDR3 and serum hepatobiliary biochemical parameters was analyzed. RESULTS: In the PNAC group, serum levels of hepatobiliary biochemical parameters and fibrosis indices increased on day 14 after birth and reached the peak on day 30 after birth, followed by a reduction on day 60 after birth. On days 14, 30, 60 and 90 after birth, the PNAC group had significantly higher serum levels of hepatobiliary biochemical parameters and fibrosis indices than the non-PNAC group (P<0.05). The PNAC group had higher relative mRNA expression of MDR3 in peripheral blood cells than the non-PNAC group (P<0.05). In the PNAC group, the relative mRNA expression of MDR3 in peripheral blood cells was negatively correlated with serum levels of hepatobiliary biochemical parameters (ALT, TBil, DBil, TBA and γ-GT) (P<0.001). CONCLUSIONS: High mRNA expression of MDR3 in preterm infants may be associated with the development of PNAC, and further studies are needed to identify the mechanism.