Q Zhang, HQ Li, HL Zheng

The impact of intrauterine growth retardation (IUGR) on the gastrointestinal (GI) tract was examined. The effects of different timing and causes of IUGR were compared in newborn IUGR rats induced by two methods, maternal starvation from the 1st day (S1) or the 17th day (S17) of gestation until spontaneous delivery and uterine arterial ligation (HAL) on the 17th day of gestation. Tissue sections of the GI tract were made and analysed using a computerized image analyser. The absolute values for GI tissue weight and relative values for GI tissue weight per unit body weight, absolute and relative values for intestinal length, intestinal diameter, GI mucosal absolute values and relative values for GI mucosal volume and absorptive area were significantly reduced in IUGR rats. The S17 group were lighter, shorter, thinner and had less mucus volume in the GI tract compared with S1 IUGR rats matched for body weight and body length, although the absolute and relative values for intestinal mucosal absorptive area were similar. The GI tissue weight, mucosal volume and absorptive area were obviously higher in S17 IUGR rats than in HAL rats matched for body weight and length; they were also higher in the normal body length rats than in the short rats in these two groups. For all the IUGR rats together, GI tissue weight correlated with body weight but not with body length, while the absolute and relative values for intestinal length and relative GI tissue weight correlated with body length but not with body weight. These results demonstrate that late-occurring IUGR or the obviously decreased placenta-uterus perfusion predicts relatively severe GI damage in similarly somatically developed newborn IDGR rats. Also, body length predicts the extent of impairment of the GI tract more closely than does body weight.