Maturity of the myenteric plexus is decreased in the gastroschisis rat model.

BACKGROUND

Amniotic fluid (AF) and its components, such as fetal urine and meconium, may lead to intestinal alterations in gastroschisis, which cause immaturity of the myenteric plexus and consequent intestinal hypomotility and malabsorption. In this study we identified morphological and histological alterations of the intestine and the myenteric plexus with two different times of exposure to AF.

METHODS

The experimental gastroschisis was achieved at two different gestational ages, on day 18.5 (E18.5) and day 19.5 (E19.5) of gestation, in fetal rats which were divided into 3 subgroups: control, sham and gastroschisis. We measured fetal body weight (BW), intestinal weight (IW) and intestinal length (IL). The layers of intestinal wall and myenteric plexus were evaluated by hematoxylin and eosin staining (HE staining) and immunofluorescence (alpha-internexin), respectively.

RESULTS

BW was not significantly different among the control, sham and gastroschisis groups at both ages. IW and IL were larger and shorter, respectively, in the gastroschisis fetuses (p < 0.001) at both ages. Intestinal diameters and wall layers presented significant differences among control, sham and gastroschisis fetuses at both ages (p < 0.001), but the time of exposure to AF compromised the serous membrane, D-II (diameter II, p < 0.001) and IL (p = 0.001). alpha-Internexin presented more intensive immunoreactivity in gastroschisis fetuses at E18.5.

CONCLUSIONS

In gastroschisis, the longer the time of exposure to AF, the more severe bowel impairment will be, especially with regard to IL and the serous layer, and the more immature the myenteric plexus will be.