ESOPHAGEAL PYLORIC LIGATION ENHANCES DEVELOPMENT OF THE MURINE FETAL STOMACH IN ORGAN-CULTURE/

Purpose: The authors hypothesized that increased intraluminal pressure in the fetal stomach would enhance development in a murine organ cult ure model. Methods: Gestation day 14 (Gd14) fetal stomachs from time-d ated pregnant CD-1 mice (term, 20 days) were maintained in organ cultu re for 7 days. Some stomachs were ligated at the gastroesophageal (GE) and pyloroduodenal (PD) junctions. Others were left unligated. Gd14, Gd16, and Gd18 stomachs were taken as well to compare organogenesis in vivo. Tissues were processed for histological, morphometric, and immu nohistochemical analysis, as well as total protein and DNA determinati on. Results: The ligated stomachs were visibly distended compared with unligated stomachs in organ culture after 7 days. The length and widt h of the 7-day in vitro ligated stomachs were significantly increased compared with unligated (2.97 +/- 0.04 mm v 2.48 +/- 0.05 mm and 2.14 +/- 0.04 mm v 1.57 +/- 0.08 mm, respectively, P<.05). Mucosal epitheli al cells showed nuclear polarization, and there was a distinct outer m uscle layer in the ligated stomachs, but not in he unligated stomachs, which demonstrated pseudostratified epithelial cells in the mucosa. T he ligated stomachs had increased in mucosal thickness compared with u nligated (31.4 +/- 1.3 um vs 24.9 +/- 0.9 mu m, p < 0.05). The ligated stomachs also had significantly increased protein and DNA con tent wh en compared with unligated stomachs (65.8 +/- 3.1 mu g and 23.3 +/- 1. 2 mu g v 55.0 +/- 2.7 mu g and 19.0 +/- 1.2 mu g, respectively, P< .05 ). However, there were no significant differ ences noted between the p rotein to DNA ratios. Immunohistochemical staining for proliferating c ell nuclear antigen (PCNA), a marker for cell proliferation, demonstra ted increased proliferative activity of the mucosal epithelial cells i n the ligated stomachs. Conclusions: Esophageal and pyloric ligation e nhanced the development of the fetal stomach in vitro in comparisen wi th unligated stomachs cultured under similar conditions. Developmental characteristics of the ligated stomachs paralleled that of Gd16 stoma chs in vivo. Copyright (C) 1998 by W.B. Saunders Company.