Catch-up growth in intrauterine growth retarded rats: its correlation with histomorphometric changes of the pituitary somatotrope cells

ABSTRACT

The aim of the present study was to examinethe long-term effects of prenatal injure onbody and craniofacial growth in intrauterinegrowth retarded (IUGR) animals and its correlationwith histomorphometric changes ofthe pituitary somatotrope population. IUGRmodel was carried out by means of uterine vesselsligation in pregnant rats at 14th day ofpregnancy. Control and sham-operated animalswere also included. The animals were Xrayedat 1, 21, and 84 days of age. Bodyweight, neural and facial variables were measured.Pituitaries were processed for lightmicroscopy and immunolabeled with anti-GH sera. Morphometry was performed bymeans of an image-analysis system. Data wereprocessed by ANOVA, and Wilcoxon tests.Body weight was significantly lower in newbornIUGR rats compared with that of theircontrol counterparts, even during postnatalgrowth. Both neurocranium and face weresimilarly affected at birth and weaning. At 84days of age, despite facial growth exhibited apartial recovery, cranial volumes remainedsmaller in IUGR animals. Quantitativeimmunohistochemistry revealed a significantdecrease in the volume and cell densities inIUGR compared to control age peers. Adequatenutritional and environmental conditionswere insufficient to reverse the effects ofa reduced uteroplacental blood supply on fetalgrowth. The timing and duration of thegrowth insult seem to be crucial for the occurrenceof catch-up body weight and cranialgrowth in the rat. The lack of complete catchupin these IUGR animals may be associatedto an alteration in the GH production (AU)

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