RESUMO
Malnutrition is one of the most important causes of normal growth disruption. Anthropometric methods are highly valuable in clinic pediatric diagnosis to determine the nutritional status of children and as recovery monitoring. In previous studies, we have demonstrated that the standards weight-age, height-age and weight-height of growing rats had similar distribution to those in normal children. However, to improve the diagnostic effectiveness of anthropometric information, statistical analysis to normally and non-normally distributed variables should be applied. One hundred Wistar rats (50 male and 50 female rats) from weaning (day = 25, weight = 35-40 g) to 70 days of age were fed with a commercial diet. Water and diet were offered "ad libitum". Body weight and height were recorded every two or four days, respectively. Percentiles of weight vs age, height vs age and weight vs height were plotted for male and female rats. The statistical criterion for classifying the anthropometric measurements into nutritional categories was based on percentiles cutoff and Z-score. The Z-score was calculated according to: Z = (standard mean value-subject value/standard deviation of standard). The statistical anthropometric categories of growing rats were similar to those obtained in children. This evidence suggest that the rat can be used as an experimental model to infer and predict the nutritional response in children.
Assuntos
Antropometria/métodos , Crescimento/fisiologia , Ratos Wistar/crescimento & desenvolvimento , Animais , Peso Corporal , Feminino , Masculino , Estado Nutricional , RatosRESUMO
Erythropoietin (EPO) is a glycoprotein which appears as the primary regulator of erythropoiesis under either normal or most of the pathologic conditions. In the rat with experimentally-reduced erythropoiesis, daily administration of 1.3 IRP units can restore the function and maintain steady-state conditions of red cell formation. This important information for the programming of both physiologic and pharmacologic studies is lacking for the mouse, in spite of the fact that most of the experiments performed on the regulation of erythropoiesis have been conducted in this species. In the present study, designed to determine EPO requirement for maintenance of steady-state erythropoiesis in the adult mouse under standard laboratory conditions, adult females of the CF#1 strain were exposed to hypobaria (18 h/day) during a 3-week period for induction of polycythemia (P). At the end of the hypoxic period. P mice were maintained at sea level conditions, as were normocythemic (N) mice during the entire experimental period. P mice were daily injected with 0, 0.5, 1.0, 1.5, or 2.0 IRP units of rHu-EPO during the 4-day period that followed the hypoxic one. The rate of erythropoiesis in N and P mice were measured by RBC-59Fe uptake. The plasma 59Fe half-clearance time was also measured in other groups of N and P mice similarly treated. One-way ANOVA showed that the only non-significant difference (P > 0.05) between N and EPO-injected P mice was established for the 1.0 unit dose group. It is thus suggested that approximately 1.0 unit of EPO should be synthesized daily in an adult mice to maintain a normal rate of erythropoiesis.
Assuntos
Eritropoese/fisiologia , Eritropoetina/fisiologia , Animais , Feminino , CamundongosRESUMO
The erythroid response to Erythropoietin (EPO) is highly dependent on dietary protein. Its operating mechanism, however, remains unsettled. The mouse spleen is an erythropoietic organ which contains an EPO-responsive cell population that can be easily amplified by administration of the hormone. The present study was performed to determine the effect of a protein-free diet offered freely to mice up to two days after injection of r-Hu EPO (1000mU/200 ul) on the response of the above population. Splenic cell suspensions from control and experimental mice were prepared in microwells containing 400 mU r-Hu EPO and appropriate medium. The response to EPO was evaluated in terms of 3H-thymidine uptake. The results obtained indicate that acutely induced protein restriction suppressed the response of the EPO-responsive splenic cell population to EPO when it was imposed on mice immediately after hormone injection, and suggest the appearance of deficient rates of differentiation of erythropoietic units by protein restriction.
Assuntos
Eritropoetina/farmacologia , Deficiência de Proteína/fisiopatologia , Baço/citologia , Animais , Diferenciação Celular/efeitos dos fármacos , Eritropoese/efeitos dos fármacos , Feminino , Camundongos , Camundongos Endogâmicos , Baço/efeitos dos fármacos , Timidina/metabolismo , TrítioRESUMO
The present study was designed to provide direct information on the protein requirement of 12-month-old-female rats for maintenance of the circulating red cell mass (RCM). Different groups (7) of rats were fed during 30 days one of seven isocaloric diets containing graded levels of casein, from 0% to 10%. RCM was determined by the radio-iron-labelled red cell dilution method at the end of experimental period. Casein requirement level for maintenance of RCM, predicted as the point on the regression line where the value of the dependent variable (delta RCM/100 g body wt) was 0, was 3.6%. This value was identical to that predicted for the maintenance of body weight, which suggests that both are interrelated and that RCM is a function of the body weight. The relation also suggests that the anaemia developing in the adult rat in response to protein depletion could be a type of physiologic adaptation between the body oxygen transport system and the body mass.