The incidence of preterm delivery has been increasing in the last two decades. It is well known that intrauterine infection is one of the main etiologies associated with preterm delivery. Inflammatory injury has also been associated with increased morbidity and poor long-term outcomes with increased incidence of Broncho-pulmonary dysplasia, Periventricular leukomalacia, and Cerebral Palsy with worse developmental outcomes in the surviving neonates. Several cytokines are involved in the inflammatory process associated with chorioamnionitis (IL-1, TNF α, IL-8, IL-6, IL-10). Antileukinate is a potent selective inhibitor of IL-8, by binding to CXC receptors on neutrophils, thereby inhibiting IL-8 induced neutrophil chemotaxis and enzyme release. We hypothesized that antenatal administration of Antileukinate can delay preterm delivery in a murine model of chorioamnionitis.
Timed pregnant adult C57BL6 mice were studied. First group received intraperitoneal (IP) injections of LPS (50 mcg/mouse) on day 15 of gestation to induce preterm delivery. Second group received LPS (same dose) in addition to daily IP injections of antileukinate (1mg/mouse) on gestational days 15, 16, and 17, or until the day of spontaneous delivery. A third group received a daily IP saline injection using the same volume till time of delivery and a fourth negative control group. Duration of pregnancy until delivery, after LPS/ saline injections and number of dead versus survivor neonates were recorded in all groups. Blood and uterine tissues from adult mice, and brain, lung, heart and intestine were collected from neonates. All collected tissues were studied for cytokines including IL-1, TNF α, IL-6, IL-8 homologues (KC), and IL-10, using ELISA techniques. Histopathological studies of uterus (adult mice), brain, lung, heart and gut (neonate) were planned.
Preliminary data showed that adult pregnant mice in first group which was treated with LPS only, gave birth within 24 hours after LPS injection with mean of 17.5±0.5 hours. In second group, all treated mice with LPS and antileukinate, gave birth after 60 hrs from first injection with mean of 85 ±10 hours. All 15 pups for first group (LPS only) were still born (100% still birth) compared to only 3 out of 16 (18.75%) in the second group (Antileukinate + LPS), with 13 live pups (81.25%). Cytokine assay of IL-6 in the serum from adult pregnant mice showed significant reduction in level of IL-6 in second group (antileukinate + LPS) (20 pg/ml) compared to first group (LPS only) (300 pg/ml) (p<0.05). Rest of the cytokine assays and histopathological studies are pending.
Preliminary data confirmed that IP injections of Antileukinate in animal model with chorioamanionitis induced by LPS, can significantly delay preterm delivery and also can significantly improve the neonatal outcome (morbidity and mortality).