Therapeutic N-Acetyl-Cysteine (Nac) Following Initiation of Maternal Inflammation Attenuates Long-Term Offspring Cerebral Injury, as Evident in Magnetic Resonance Imaging (MRI)

Abstract

Maternal infection/inflammation may induce fetal inflammatory responses, which have been associated with long-term offspring cerebral injury. We previously demonstrated that prophylactic N-Acetyl-Cysteine (NAC), administered prior to and following maternal lipopolysaccharide (LPS), reduced offspring cerebral injury as evident on MRI. In the present study, we used MRI to examine the effect of therapeutic NAC following maternal LPS-induced inflammation on neonatal brain injury. Pregnant Sprague-Dawley dams (n = 6) at day 18 of gestation received either intraperitoneal injection of LPS or saline (Control) at time 0. Animals were randomized to receive intravenous injection (tail vein) of NAC or saline at time +30 min. Pups were delivered spontaneously and allowed to mature until postnatal day 25. Male offspring (6-8 per group) were examined by MRI and analyzed using voxel-based analysis. Diffusion Tensor Imaging (DTI), an advanced MRI technique, was performed and quantitative parameters extracted (mean and radial diffusivity) and used to assess white and gray matter brain injury. Offspring of LPS-treated dams exhibited significantly increased mean, axial and radial diffusivity (RD) levels in white and gray matter consistent with cerebral injury. In contrast, offspring of NAC-treated LPS PS dams demonstrated reduced mean, axial and RD levels in most regions; similar to the saline group. Maternal NAC treatment following maternal inflammation significantly influenced brain micro-structure integrity as demonstrated by MRI-DTI scans. These findings suggest that maternal NAC therapy may be effective in human pregnancies associated with maternal/fetal inflammation, such as preterm rupture of membranes and chorioamnionitis.

Keywords: N-Acetyl-Cysteine; brain injury; inflammation; therapy.