Objective To observe the effect of human β-defensins-2(HBD-2) for chorioamnionitis(HCA) pregnant women before term premature rupture of fetal membrane(PROM) process,and explore toll-like receptor 4 / nuclear factor-κ B (TLR4 / NF-κB) predominate role in the process of signal transduction pathway in the mechanism.Methods Fifty five women with PROM were enrolled in the study.According to the Results of pathological diagnosis of membranes,pregnant women with PROM divided into histological chorioamnionitis,HCA and non-HCA.The same sample without PROM pregnancies matching the same gestational ages were recruited as control group.We examined the messenger RNA(mRNA) of TLR4,NF-κB p65 and HBD-2 in placenta and fetal membrane real-time reverse transcription polymerase chain reactions by dsDNA-binding dyes of SYBR Green.Results (1)In the placenta,the level of TLR-4(17.15±4.52),NF-κB p65(47.11±14.23),HBD-2mRNA(27.35±2.67) in PROM group were significantly higher than the level of TLR-4(7.21±3.25),NF-κB p65(30.51±13.05),HBD-2mRNA(13.55±0.8) in control group(t=-1.966,-1.474,-1.754,P<0.05).In the fetal membrane,the level of TLR-4(18.54±3.35),NF-κB p65(49.29±16.18),HBD-2mRNA(25.19±3.39) in PROM group were significantly higher than the level of TLR-4(6.88±2.75),NF-κB p65(32.41±11.45),HBD-2mRNA(13.80±2.21) in control group(t=-2.378,-1.487,-1.847,P<0.05).In the placenta,the level of TLR-4(19.35±4.12),NF-κB p65(49.3±13.36),HBD-2mRNA(31.54±2.43) in HCA group were significantly higher than the level of TLR-4(6.71±2.25),NF-κB p65(32±12.25),HBD-2mRNA(7.41±0.45) in non-HCA group(t=-3.456,-1.547,-5.324,P<0.05).The level of TLR-4(7.78±2.65),NF-κB p65(8.48±1.01),HBD-2mRNA(30.45±11.42) in HCA group were significantly higher than the level of TLR-4(7.78±2.65),NF-κB p65(30.45±11.42),HBD-2mRNA(8.48±1.01) in non-HCA group(t=-3.654,-1.654,-6.352,P<0.0).(3)HCA group women:there were positive correlations between TLR4mRNA and NF-κB p65 mRNA,TLR4mRNAand HBD2 mRNA,TLR4mRNA and HBD2 mRNA(r=0.334,0.427,0.432,0.562,0.471,0.392,P<0.01)(4;)Non-HCA group women:there were positive correlations between HBD-2 and NF-κB p56(r=0.492,0.298,P<0.01),there had no correlation betweenTLR4mRNA and NF-κB p65mRNA,TLR4mRNAand HBD2 mRNA(P>0.05).Conclusion Linear positive correlation of TLR4,NF-κB and HBD2 indicated that TLR4/NF-κB/HBD2 signal transduction pathway may be involved in the development of preterm premature rupture of membrane associated with histologic chorioamnionitis.