Expression and regulation of metallothioneins in myometrium and fetal membranes

Problem Metallothioneins ( MT s) play important roles in regulating oxidative stress, inflammation, and hormone signaling. These processes play a major role in labor at term and preterm. The aims of this study were to characterize (a) temporal‐ and labor‐associated changes and (b) the effect of pro‐inflammatory and pro‐labor insults on the expression of MT 1 isoforms, MT 2A, MT 3, and MT 4 in fetal membranes and myometrium. Method of Study The expression of MT s was assessed in fetal membranes and myometrium from nonlaboring and laboring women at preterm and term by RT ‐ qPCR . Tissue explants were used to assess the effect of pro‐inflammatory cytokines and Toll‐like receptor ( TLR ) ligands on the expression of MT s in fetal membranes and myometrium. Results In fetal membranes, the expression of MT 1A, MT 1E, MT 1F, MT 1X, and MT 2A was higher at term compared with preterm. Preterm labor and preterm histological chorioamnionitis were associated with increased expression of MT 1A, MT 1G, MT 1M, MT 1X, MT 2A, and MT 3. Term labor was associated with increased expression of MT 1A, MT 1F, MT 1X, MT 2A, and MT 3 in fetal membranes and expression of MT 1A, MT 1E, MT 1F, MT 1G, MT 1M, MT 1X, MT 2A, and MT 3 in myometrium. Pro‐inflammatory cytokines and TLR ligands increased the expression of MT 1A, MT 1E, MT 1F, MT 1G, MT 1H, MT 1X, and MT 2A in fetal membranes and myometrium. Conclusion Temporal‐, labor‐, and infection‐associated increases in MT 1 isoforms, MT 2A, and MT 3 have been observed in fetal membranes and/or myometrium. Furthermore, pro‐inflammatory cytokines and bacterial and viral products increased the expression of MT 1 isoforms, MT 2A, MT 3, and MT 4 mRNA expression in fetal membranes and myometrium.