Abstract:Objective To study the associations of absent in melanoma 2 (AIM2) in the fetal membrane,maternal blood and cord blood with the premature rupture of fetal membranes (PROM) complicated by histologic chorioamnionitis (HCA) to provide reference for the early diagnosis of infectious PROM. Methods From May 2018 to May 2019,120 PROM patients (experimental group) and 30 normal full-term pregnant women receiving cesarean section (control group) were selected as study subjects.According to the pathological results of fresh fetal membranes after delivery,the experimental group was subdivided into PPROM combined with HCA group (group A),pre-premature rupture of fetal membranes(TPROM) combined with HCA (group B),PPROM with non-HCA group(group C) and TPROM with non-HCA group (group D).The expression levels of AIM2 protein,AIM2 and caspase-1 and mRNA levels of AIM2 and caspase-1 in fetal membranes were respectively detected by immunohistochemistry,immunofluorescence and qRT-PCR.ELISA was used to detect the levels of AIM2,IL-1β and IL-18 in maternal and umbilical blood. Results The protein and mRNA expressions of AIM2 and caspase-1 in group A and B increased compared with control group,group C and D (all P<0.01),and were similar between group C,D and control group (all P>0.05).The protein expressions of AIM2 and caspase-1 showed consistent changes among the four groups.The levels of AIM2,IL-1β and IL-18 in maternal blood and cord blood were significantly higher in group A and B than those in control group,group C and D(P＜0.05,P＜0.01),and there were no statistical differences in them between group C,D and control group (all P>0.05). Conclusions High expressions of AIM2 and caspase-1 and high levels of IL-1β,IL-18 may be related to PROM with HCA,but not to non-infectious PROM.AIM2 and its downstream IL-1β and IL-18 may have predictive significance for PROM with HCA.