Study on the levels of microRNA-146b, microRNA-155 and microRNA-30b in human milk and their correlation with maternal and infant health / 中华实用儿科临床杂志

ABSTRACT

Objective To explore the expression levels of immune-related microRNA-146b (miR-146b),microRNA-155 (miR-155) and microRNA-30b(miR-30b) in human breast milk and its relationship with maternal and infant's health.Methods One hundred and thirty-four mothers and their infants from obstetrical department were recruited in the study after delivery.The subjects were divided into 2 groups,breast feeding group(n =86) and formula-feeding group(n =48),and were followed up 3 months after delivery.Breast milk samples were collected at 2-5 days after delivery(colostrum) and 3 months after delivery(mature milk).The expression levels of microRNAs in milk samples were detected by real-time PCR.The relationship between levels of microRNAs and maternal and infant-related factors was analyzed.Results 1.MiR-146b,miR-155 and miR-30b expressions were abundant both in human colostrums (5.950 ± 0.823,3.899 ± 0.920,4.057 ± 0.604) and mature milk (4.840 ± 0.805,2.128 ± 0.969,4.929 ± 0.566).The levels of miR-146b and miR-155 were higher in colostrum than that of mature milk (t =7.716,10.215,all P ＜ 0.01),while the level of miR-30b was higher in mature milk than that of colostrums(t =-8.626,P ＜ 0.0l).2.Additionally,the level of miR-30b was negatively correlated with maternal pre-pregnancy body mass index (r =-0.298,P ＜ 0.01).3.The levels of miR-146b and miR-30b were higher in mothers giving birth by vaginal delivery than those who underwent cesarean section(t =2.356,3.108,all P ＜0.05).4.The levels of miR-146b and miR-155 were higher in colostrum-fed girls than boys (t =-2.204,-2.985,all P ＜ 0.05).5.The level of miR-146b in mature milk was negatively correlated with 3-month-old infant' s Z score of body weight (r =-0.425,P ＜ 0.05) and body length (r =-0.569,P ＜ 0.01).6.During follow-up,the incidence of baby eczema in breast feeding group (8.82％,3/34 cases) was lower than that in formula milk feeding group(29.17％,14/48 cases) (x2 =5.012,P =0.025).Conclusions The levels of immunocompetent microRNAs in human milk are influenced by the lactation period,maternal prepregnancy body mass index,mode of delivery and infant sex.The immune-related microRNAs in human milk could be involved in the regulation of infant's immunity and growth.