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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Animals, Cervical Ripening, Cyclooxygenase 2, Escherichia coli Infections, Female, Gene Expression, Interleukin-1, Mice, Mice, Inbred C57BL, Mice, Knockout, Myometrium, Obstetric Labor, Premature, Pregnancy, RNA, Messenger, Receptors, Interleukin-1, Receptors, Interleukin-1 Type I, Receptors, Tumor Necrosis Factor, Type I, Signal Transduction, Tumor Necrosis Factor-alpha.
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Is signaling via the type I IL-1 and TNF receptors necessary for bacterially induced preterm labor in a murine model? Context: We have shown previously that interleukin 1 (IL-1) signaling is not necessary for bacterially induced preterm delivery in mice. We now test whether combined signaling of IL-1 and tumor necrosis factor (TNF) is critical for this process. Female mice lacking the type I receptors for IL-1 and TNF (Il1r1/Tnfrsf1a double-knockouts) and normal controls underwent intrauterine inoculation with killed Escherichia coli bacteria on day 14.5 of a 19- to 20-day gestation. Preterm delivery rates within 48 hours were recorded and gene expression was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Il1r1/Tnfrsf1a double-knockout mice had significantly lower rates of preterm delivery than controls (8% vs 69% with 7 x 10(7) bacteria, P = .002, and 52% vs 81% with 1.4 x 10(8) bacteria, P = .003) and significantly lower myometrial levels of cyclooxygenase (COX)-2, but not COX-1 mRNA. There were no genotype- or treatment-related differences in cervicovaginal and lower uterine expression of mRNAs for a variety of genes associated with cervical ripening.
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The combination of IL-1 and TNF signaling plays a critical role in bacterially induced labor and myometrial COX-2 production in the mouse. Cervical gene expression patterns during bacterially induced preterm labor suggest fundamental differences from spontaneous term labor in the cervical ripening process. Final Decision: yes