Investigation of the intra-abdominal oesophagus and hiatus in fetal rats with oesophageal atresia and tracheo-oesophageal fistula

After surgical management of their oesophageal atresia (OA) and tracheo-oes ophageal fistula (TOF), most patients exhibit evidence of gastrooesophageal reflux (GOR) and many have oesophagitis. However, the aetiology of the GOR is still controversial. This study was undertaken to document whether ther e are congenital abnormalities in the intra-abdominal oesophagus and the hi atus in the fetal rat with OA and TOF following exposure to adriamycin (ADR ). Time-pregnant rats were injected daily with either saline or 2 mg/kg ADR intraperitoneally on gestational days (GD) 6-9. The fetuses (n = 56) from 8 litters were harvested on GD 21 for examination. The length of the oesoph agus between the diaphragmatic crura and the gastro-oesophageal junction (G OJ) and the sizes of the stomach and the oesophageal hiatus were measured u nder a dissecting microscope. The length of the oesophagus between the diap hragmatic crura and the GOJ in the ADR-treated fetuses (0.85 +/- 0.37 mm) w as significantly shorter than in control fetuses (2.41 +/- 0.32 mm) (P < 0. 0001). The size of the stomach in ADR-treated fetuses (5.30 <plus/minus> 1. 01 mm) was significantly smaller than in the controls (8.07 +/- 0.49 mm) (P < 0.001). Moreover, the size of the oesophageal hiatus in ADR-treated fetu ses (1.16 <plus/minus> 0.43 mm) was markedly larger than in the controls (0 .32 +/- 0.1 mm) (P < 0.0001). These results showed that the congenital abno rmalities in ADR-treated rat fetuses may account for the oesophageal functi onal disorders seen after surgical correction in patients who have OA and T OF.