Growth deceleration and bone metabolism in nutritional dwarfing rats

Nutritional status as well as energy and protein intake are critical regula tors of IGF-1 and IGFBP-3 and contribute to the modulation of bone remodeli ng and formation. The purpose of this study was to investigate on an experi mental model with nutritional dwarfing (ND), whether the alterations on bod y growth velocity, energy metabolism and body composition could affect seru m concentrations of IGF-1 and IGFBP-3 and bone (tibiae and mandible) histol ogy and histomorphometry. Twenty-one male weanling Wistar rats (body weight = 38.20 +/- 0.94 g) were randomized to three groups: seven of them were ki lled at day = 0 (CO, n = 7); control (C, n = 7); and experimental 80 (E80, n = 7). During 4 weeks, C was fed ad libitum with a 1: 1 carbohydrate to fa t diet. E80 was being underfed with the same diet by 80% and the following parameters were measured: weight (Wt) for length (L) ratio z-score; oxygen consumption (VO2); body composition (BC) by EM-SCAN SA 3000. At t = 28, E80 and C were killed. Serum IGF-1 and IGFBP-3 and bone histology and histomor phometry were performed on C0, E80 and C. E80 showed Wt for L z-score betwe en lean and adequate, a decrease in VO2 according to body proportions, a BC of a delayed puberty individual, IGF-1 and IGFBP-3 decreased by 56 and 53% , respectively. Tibiae's hematopoyetic and adipose bone marrow areas were c ombined, with sealing trabeculae on metaphyseal areas. This study suggests that there is a relationship among growth deceleration in ND rats and struc tural alterations on tibiae.