Inflammatory cytokine mRNA in human gestational tissues: implications for term and preterm labor

To determine if inflammatory cytokine mRNA in gestational tissues is present only in the setting of infection-associated preterm labor or under several other clinical conditions.

Human gestational tissues were collected from 51 women experiencing 1) term cesarean delivery without labor, 2) normal term vaginal delivery, 3) preterm cesarean delivery without labor, 4) preterm vaginal delivery without chorioamnionitis, and 5) preterm vaginal delivery with concomitant chorioamnionitis. Decidua, chorion, and amnion were isolated, total RNA from each tissue was extracted, and the presence of inflammatory cytokine mRNA was determined by polymerase chain reaction. Interleukin (IL)-1 beta, IL-6, IL-8, and tumor necrosis factor-alpha mRNA was detected using specific oligonucleotide primers.

Interleukin-1 beta mRNA was rarely found in tissues preterm without labor but was readily detected in both maternal and fetal tissues after labor, regardless of gestational age. Interleukin-6 mRNA was rare in tissues from the nonlaboring patient but was found in almost all tissues after labor. Interleukin-8 mRNA was detected in all tissues at term, both in nonlaboring and laboring patients. Tumor necrosis factor-alpha mRNA was detected in only 20-50% of tissues after labor, and was rarely detected in the absence of labor.

Inflammatory cytokine mRNA is commonly expressed in human gestational tissues after normal labor and preterm labor with or without associated intrauterine infection. There was no difference in the pattern of expression of mRNA inflammatory cytokine in women who did or did not have clinically evident intrauterine infection.