The effect of fetal stabilization using morphine hydrochloride on neonatal rats.

We previously showed that fetal stabilization (FS) could improve the prognosis of congenital diaphragmatic hernia (CDH) patients. The aim of this study is to elucidate the effect of FS in normal neonatal rats. Pregnant Sprague-Dawley rats were treated by experimental protocols on day 21 of gestation. In the FS-group, they received morphine hydrochloride via the placenta before undergoing a caesarean section. In the control group (C-group), they received no morphine hydrochloride. All neonatal rats were managed under mechanical ventilation. We collected the blood samples and bronchoalveolar lavage fluid (BALF) at birth and at 4 h after birth in both groups and the cytokine levels in those samples were measured. The specimens obtained from the right lung were stained with anti-TNF-alpha antibody. The levels of serum TNF-alpha at birth and IL-6 at 4 h after birth in the FS-group decreased, in comparison to those in the C-group. The staining intensity of anti-TNF-alpha antibody in the FS-group was weaker than that in the C-group. FS reduced the production of inflammatory cytokines on neonatal rats, which was controlled by mechanical ventilation. This effect may beneficially reduce the occurrence of persistent pulmonary hypertension of neonate (PPHN), which is induced by stress in CDH patients.