Volume 29, Issue 4, 2020
DOI: 10.24205/03276716.2020.854
Effects of Vitamin D on Infection-Induced Premature Delivery in Rats
Abstract
Objective: To explore the neuroprotective effects of vitamin D on premature rats with intrauterine infection of white matter damage (WMD).
Methods: A total of 27 pregnant rats were randomly divided into normal group (n=9), model group (n=9) and experimental group (n=9). At 7 d after pregnancy, the rats in experimental group were gavaged with vitamin D (800 IU/d, 7 d in total), while those in normal group and model group were gavaged with an equal amount of normal saline. At 14 d after pregnancy, lipopolysaccharide (LPS, 400 μg/kg) was intraperitoneally injected in model group and experimental group to replicate the infection-induced premature delivery model. Then the content of serum transforming growth factor-β1 (TGF-β1), and amniotic fluid tumor necrosis factor-α (TNF-α) and vitamin D-binding protein (VDBP) was detected by ELISA. At 7 d after birth, neonatal rats in the 3 groups were perfused with formaldehyde to harvest the brain, and the levels of cluster of differentiation 68 (CD68) and glial fibrillary acidic protein (GFAP) in brain tissues were detected using immunofluorescence staining. The neurological behaviors were observed through open field test, suspension test, slope test and anti-capture reaction test at 30 d after birth.
Results: The hippocampal pyramidal cells were arranged neatly and had clear layers in normal group. In model group, the cells had unclear boundaries and disordered layers, and the number of cells declined. In experimental group, the cellular layer was clearer than that in model group. Model group had higher content of amniotic fluid TNF-α and VDBP, and lower content of serum TGF-β1 than normal group (P<0.05). In model group and experimental group, the levels of CD68 and GFAP in brain tissues significantly rose compared with those in normal group (P<0.05). The levels of CD68 and GFAP in brain tissues significantly declined in experimental group compared with those in model group (P<0.05). At 30 d after birth, the neurological behavior score of neonatal rats was significantly lower in model group than that in normal group (P<0.05), while it was significantly higher in experimental group than that in model group (P<0.05). The content of amniotic fluid TNF-α was lower in experimental group than that in model group (P<0.05), while the content of amniotic fluid VDBP and serum TGF-β1 had no statistically significant differences between the two groups (P>0.05).
Conclusion: Vitamin D, through inhibiting the pro-inflammatory factor TNF-α, can improve the nervous system development and cognitive function of premature rats with intrauterine infection of WMD.
Keywords
vitamin D; infection-induced premature delivery; CD68; GFAP; TNF-α