4 resultados para Resistência à insulina Teses
em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo
Resumo:
Background: In the literature, there are several experimental models that induce scoliosis in rats; however, they make use of drugs or invasive interventions to generate a scoliotic curve. Objectives: To design and apply a non-invasive immobilization model to induce scoliosis in rats. Methods: Four-week old male Wistar rats (85 +/- 3.3 g) were divided into two groups: control (CG) and scoliosis (SG). The animals in the SG were immobilized by two vests (scapular and pelvic) made from polyvinyl chloride (PVC) and externally attached to each other by a retainer that regulated the scoliosis angle for twelve weeks with left convexity. After immobilization, the abdominal, intercostal, paravertebral, and pectoral muscles were collected for chemical and metabolic analyses. Radiographic reports were performed every 30 days over a 16-week period. Results: The model was effective in the induction of scoliosis, even 30 days after immobilization, with a stable angle of 28 +/- 5 degrees. The chemical and metabolic analyses showed a decrease (p<0.05) in the glycogenic reserves and in the relationship between DNA and total protein reserves of all the muscles analyzed in the scoliosis group, being lower (p<0.05) in the convex side. The values for the Homeostatic Model Assessment of Insulin Resistance indicated a resistance condition to insulin (p<0.05) in the scoliosis group (0.66 +/- 0.03), when compared to the control group (0.81 +/- 0.02). Conclusions: The scoliosis curvature remained stable 30 days after immobilization. The chemical and metabolic analyses suggest changes in muscular homeostasis during the induced scoliosis process.
Resumo:
OBJETIVOS: Comparar os parmetros metablicos, a composio corporal e a fora muscular de mulheres com Sndrome dos Ovrios Policsticos (SOP) em relao a mulheres com ciclos menstruais ovulatrios. MTODOS: Estudo caso-controle com 27 mulheres com SOP e 28 mulheres controles com ciclos ovulatrios, com idade entre 18 e 37 anos, ndice de massa corprea entre 18 e 39,9 kg/m, que no praticassem atividade fsica regular. Nveis sricos de testosterona, androstenediona, prolactina, globulina carreadora dos hormnios sexuais (SHBG), insulina e glicemia foram avaliados. ndice de andrgeno livre (FAI) e resistência insulina (por HOMA) foram calculados. As voluntrias submetidas avaliao de composio corporal por dobras cutneas e absorciometria de raio X de dupla energia (DEXA) e testes de fora muscular mxima de 1-RM em trs exerccios aps procedimento de familiarizao e de fora isomtrica de preenso manual. RESULTADOS: Os nveis de testosterona foram mais elevados no grupo SOP em relao ao CO (68,020,2 versus 58,212,8 ng/dL; p=0,02), assim como o FAI (282,5223,8 versus 127,077,2; p=0,01), a insulina (8,47,0 versus 4,02,7 uIU/mL; p=0,01), e o HOMA (2,32,3 versus1,00,8; p=0,01). O SBHG foi inferior no grupo SOP comparado ao controle (52,543,3 versus 65,127,4 nmol/L; p=0,04). No foram observadas diferenas significativas na composio corporal com os mtodos propostos entre os grupos. O grupo SOP apresentou maior fora muscular no teste de 1-RM nos exerccios supino reto (31,24,75 versus 27,83,6 kg; p=0,04) e cadeira extensora (27,96,2 versus 23,44,2 kg; p=0,01), assim como nos testes de fora isomtrica de preenso manual (5079,61035,7 versus 4477,369,6 kgf/m; p=0,04). Ser portadora de SOP foi um preditor independente de aumento de fora muscular nos exerccios supino reto (estimativa (E)=2,7) (p=0,04) e cadeira extensora (E=3,5) (p=0,04). Assim como o IMC no exerccio de fora isomtrica de preenso manual do membro dominante (E=72,2) (p<0,01), supino reto (E=0,2) (p=0,02) e rosca direta (E=0,3) (p<0,01). Nenhuma associao foi encontrada entre HOMA-IR e fora muscular. CONCLUSES: Mulheres com SOP apresentam maior fora muscular, sem diferena na composio corporal. A RI no esteve associada ao desempenho da fora muscular. Possivelmente, a fora muscular pode estar relacionada aos nveis elevados de andrognios nessas mulheres.
Resumo:
Insulin resistance is a metabolic disorder in which target cells fail to respond to normal levels of circulating insulin. Insulin resistance has been associated with presence of acanthosis nigricans and acrochordons. It is known that early diagnosis and early initial treatment are of paramount importance to prevent a series of future complications. These dermatoses may represent an easily identifiable sign of insulin resistance and non-insulin-dependent diabetes.
Resumo:
LLong-chain fatty acids are capable of inducing alterations in the homoeostasis of glucose-stimulated insulin secretion (GSIS), but the effect of medium-chain fatty acids (MCFA) is poorly elucidated. In the present study, we fed a normoenergetic MCFA diet to male rats from the age of 1 month to the age of 4 months in order to analyse the effect of MCFA on body growth, insulin sensitivity and GSIS. The 45% MCFA substitution of whole fatty acids in the normoenergetic diet impaired whole body growth and resulted in increased body adiposity and hyperinsulinaemia, and reduced insulin-mediated glucose uptake in skeletal muscle. In addition, the isolated pancreatic islets from the MCFA-fed rats showed impaired GSIS and reduced protein kinase Ba (AKT1) protein expression and extracellular signal-related kinase isoforms 1 and 2 (ERK(1/2)) phosphorylation, which were accompanied by increased cellular death. Furthermore, there was a mildly increased cholinergic sensitivity to GSIS. We discuss these findings in further detail, and advocate that they might have a role in the mechanistic pathway leading to the compensatory hyperinsulinaemic status found in this animal model.
