Effect of Acidosis and Hypoxia on Intestinal Blood Flow of Sheep Fetus

Abstract

In sheep fetuses 110–130 days of age acidosis (blood pH 6.95; produced by infusion with 1.1 M lactic acid) significantly lowered blood flow (ml/min/100 g) to the full thickness wall of the jejunum from 135 ± 11 to 93 ± 14 and in the full thickness wall of the ileum from 122 ± 13 to 95 ± 11. The decrease was mainly due to the decline in blood flow to mucosa of the segment, where flow decreased from 182 ± 20 to 83 ± 14 in the jejunum and from 130 ± 10 to 107 ± 9 in the ileum. Fetal hypoxemia (PaO₂ of 14.9 mm Hg; induced by allowing ewes to breath 11.1% O₂ and 88.9 % nitrogen) reduced blood flow only to the jejunal mucosa from 142 ± 14 to 99 ± 16. The reduction in blood flow to the full thickness wall of the jejunum and the ileum did not change significantly from the control period, when PaO₂ was 25 mm Hg.

Small Intestinal Development in Growth‐Retarded Fetal Sheep

“…It is known, for instance, that organ weights are disproportionately affected in IUGR (15), but its effects on the structural development of specific organs have received little attention. The development of the gastrointestinal tract is likely to be affected by placental insufficiency, as the blood supply to the gut is known to be reduced during fetal hypoxia (16)(17)(18) , and it has been shown that mucosal blood flow is affected most (19). Intrauterine growth retardation induced by restriction of maternal protein intake has been shown to result in retarded gastrointestinal development in rats (10,20,21), and it was of interest to determine if similar changes accompanied growth retardation induced by restriction of placental function in fetal sheep.…”