Effects of intrauterine growth retardation on development of the gastrointestinal tract in neonatal pigs.
BACKGROUND
Intrauterine growth retardation (IUGR) is a common problem in human and other species and increases the risk of death of the fetus and newborn during the perinatal period.


OBJECTIVE
This study was conducted to examine the influences of intrauterine growth retardation (IUGR) on development of the gastrointestinal tract in newborn pigs.


METHODS
Ten animals from five litters were divided into five piglets with IUGR and five with normal birth-weight (NW). The IUGR category comprised animals with a birth weight 2 SD below the mean birth weight of the total population, while the NW category included animals with a birth weight within one SD of the mean birth weight in the total population. Animals were anesthetized and sampled within 2-4 h after birth and without suckling. The morphological changes of intestine and stomach of IUGR piglets were compared with NW ones. The expressions of IGF-I and receptors for growth hormone and insulin in intestinal mucosa were semiquantified using reverse transcription PCR.


RESULTS
The results of our study indicated that the weights of the stomach, small intestine and small intestinal mucosa were significantly lower in IUGR compared with NW piglets (p<0.01). In addition, the lengths of the small intestine and colon in IUGR pigs were also significantly less than those of NW (p<0.05). Furthermore, insulin-like growth factor-I (IGF-I) mRNA level in intestinal mucosa of IUGR piglets was increased significantly (p<0.05), and the expression mRNA levels of insulin receptor and growth hormone (GH) receptor in the mucosa in IUGR piglets showed a tendency to be lower (p=0.17 and p=0.11, respectively) than those of the NW animals.


CONCLUSIONS
We conclude from the data that IUGR affects intestinal growth and morphology and is in associated with altered gene expression of growth-related proteins. We speculate that the morphological change and associated altered endocrine homeostasis contribute to lower growth rates of pigs affected by IUGR.
Wang
Tian
T
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China. tianwang@njau.edu.cn
Huo
Yong Jiu
YJ
Shi
Fangxiong
F
Xu
Ruo Jun
RJ
Hutz
Reinhold J
RJ
D000818:Animals; D000831:Animals, Newborn; D001724:Birth Weight; D005317:Fetal Growth Retardation / Q000378:metabolism / Q000473:pathology*; D041981:Gastrointestinal Tract / Q000254:growth & development* / Q000473:pathology / Q000648:ultrastructure; D015870:Gene Expression; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D009929:Organ Size; D012313:RNA / Q000737:chemistry / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000737:chemistry / Q000235:genetics; D017526:Receptor, IGF Type 1 / Q000235:genetics / Q000378:metabolism; D011972:Receptor, Insulin / Q000235:genetics / Q000378:metabolism; D011986:Receptors, Somatotropin / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine / Q000254:growth & development*
D012337:RNA, Ribosomal, 18S; D011986:Receptors, Somatotropin; D012313:RNA; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1; D011972:Receptor, Insulin