Tissue was allowed to equilibrate for 30 min. Cumulative dose responses were

performed after 30 min of spontaneous contractions were recorded to serve as baseline contractility. At the end of the experiment 10−7 m oxytocin was added to demonstrate strip viability. Concentrations from 0·1 to 100 μm were added every 20 min at the time of organ bath wash out. Contractility was analysed using the Powerlab software V 5.5.6 (ADI instruments, Oxford, UK) using the peak parameters extension. Data were transferred from the datapad of the Powerlab software onto an excel spreadsheet for analysis. Response to treatment was measured by normalizing c-Met inhibitor to baseline spontaneous contractility and divided by the relevant time-point for the vehicle control. Experimental groups consisted of at least three replicates unless otherwise stated. Statistical

analysis was performed with Graph-Pad Prism v5 (GraphPad Software, San Diego, CA). One-way analysis of variance or analysis of variance of repeated measures was conducted, with either Dunnett’s or Bonferroni’s multiple comparisons tests. Samples with P < 0·05 were considered to be statistically significant. Pexidartinib CRTH2 mRNA was detected in murine myometrium by RT-PCR, using L-19 as a housekeeping gene. No significant difference in CRTH2 expression was seen between the treatment groups (Fig. 1). Amplification of CRTH2 was seen by cycle 33 and L-19 by cycle 19. The CRTH2 agonists PGD2 and 15dPGJ2 increase the expression of CR3 (CD11b) on eosinophils and basophils via CRTH2.[15, 27] Before experiments with the CRTH2 agonist Pyl A, activity at the CRTH2 receptor was confirmed by demonstrating up-regulation of CR3 (CD11b) in human eosinophils. We used flow cytometry to detect CR3 (CD11b) expression on eosinophils, identified by high intensity CD49d expression and forward and side scatter characteristics (Fig. 2). Up-regulation of CR3 (CD11b)

expression with Pyl A treatment was demonstrated by an increase in mean fluorescence intensity of CD11b-PE (P < 0·01). Tyrosine-protein kinase BLK This effect was attenuated with previous incubation of cells with the CRTH2 antagonist GSKCRTH2X (Fig. 2a,b). The effect of Pyl A was identical to the effect of 15dPGJ2 in causing increased expression of CR3 (Fig. 2c). We sought to determine if the CRTH2 agonist Pyl A had the same tocolytic and feto-protective effect as 15dPGJ2 in delaying preterm labour in LPS-treated mice. A dose–response effect was demonstrated with LPS (serotype 0111:B4) since varying potencies can be seen between serotypes and within batches.[28] Administration of 20 μg LPS led to reliable preterm delivery with the least variation between mice (Fig. 3a). No surviving pups at the time of delivery were seen with concentrations above 10 μg (Fig. 3b). Subsequent experiments were performed with 20 μg LPS.