The immunomodulatory and anti-apoptotic effect of dexamethasone in imminent preterm labor: an experimental study.

The study was designed to investigate the effect of dexamethasone (DEX) on the latency period to delivery in a murine model of preterm labor. To this purpose, pregnant mice were randomly assigned in groups: the control group received water for injection (n=20), the preterm labor group was injected with lipopolysaccharide (LPS) (n=22), while the glucocorticoids group was administered DEX either 1h before (n=17) or after (n=7) lipopolysaccharide. In a first set of experiments animals were monitored to record perinatal outcomes. In another set of experiments, the remaining animals were sacrificed eight h after interventions. Fetuses were homogenized to measure tumor necrosis alpha in supernatants. Maternal splenocytes were isolated and stimulated for cytokine production. Serum of mice was incubated with donor cells from healthy pregnant and non-pregnant animals to induce apoptosis. LPS induced preterm labor but treatment or pretreatment with DEX delayed parturition exerting a favorable impact on survival of delivered fetuses. DEX inverted the increase of fetoplacental tumor necrosis alpha levels. Serum of LPS-stimulated mice induced apoptosis of splenocytes of either pregnant or non-pregnant healthy mice; this was reversed after incubation of splenocytes with serum coming from DEX pre-treated mice. The presented findings suggest that DEX administered either as pre-treatment or treatment prolonged gestation and promoted neonatal survival in a sterile murine model of preterm labor. These favorable outcomes were closely linked to alterations in both immune and apoptotic responses of animals.

Alterations in the cellular component of the maternal immune system in a murine preterm delivery model.

OBJECTIVE: Investigate changes in the cellular component of maternal immune system in a murine preterm delivery (PTD) model. METHODS: C57BL/6 J mice were mated and on day 14.5 after plugging either whole blood was harvested or Escherichia coli lipopolysaccharide (LPS) was intraperitoneally injected. PTD resulted within 24 h. Ten to twelve hours after LPS injection (initiation of labor), whole blood was harvested. Annexin-V, CD3, CD4, CD8, CD80 and CD86 were counted after running through flow cytometer with gating for mononuclear cells. Control group consisted of non-pregnant mice. RESULTS: Rate of apoptosis of monocytes and lymphocytes and expression of CD80(+) and CD86(+) was increased in non-pregnant mice after LPS injection (p = 0.009, p = 0.002, p < 0.001 and p = 0.005, respectively), but remained unaltered in pregnant mice. Expression of CD3(+)/4(+) and CD3(+)/8(+) on lymphocytes was increased after LPS injection in both pregnant (p = 0.001, p = 0.011, respectively) and non-pregnant mice (p = 0.008, p < 0.001, respectively). CONCLUSIONS: Cellular component of maternal non-specific immune system is remain suppressed in pregnant mice, whereas specific immune responses of pregnant mice to infection are similar to these of non-pregnant mice.