Study of genetic and protein expression of myoglobin and cytoglobin in rat model with subclinical hypothyroidism

• Grant number: 13/11910-8
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): September 01, 2013
• Effective date (End): August 31, 2014
• Field of knowledge: Health Sciences - Medicine - Pathological Anatomy and Clinical Pathology
• Principal researcher: Gisele Giannocco
• Grantee: Micaela Frasson Montero
• Home Institution: Faculdade de Medicina do ABC (FMABC). Organização Social de Saúde. Fundação do ABC. Santo André , SP, Brazil

Abstract

Subclinical hypothyroidism (SH) is associated with an increased risk of cardiovascular disease. Myoglobin (Mb) and cytoglobin (Cygb) are proteins that work as reservoirs of oxygen and protect against reactive oxygen species in the cardiac muscle of rats with SH, however, the mechanisms that regulate its expressions are still unclear. Objectives: to investigate levels of gene and protein expressions of Mb and Cygb, and evaluate gene expression of antioxidant defense proteins: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) in rats with HS.Methods: Male Wistar rats, 8 weeks old, will be divided into the following groups (n=8, each group): (a) Control (C): rats that received saline ip and euthanasia 20 days after sham surgery; (b) hypothyroid (Tx): rats underwent total thyroidectomy and treated with methimazole (0.01%) + saline ip for 20 days and euthanasia after this period; (c ) hyperthyroid (Tx + T4): Tx rats that received T4 (0.8 ¼g/100g dose, ip) for 5 days and euthanized after this period; (d) subclinical hypothyroidism (SH): rats undergoing partial thyroidectomy treated with saline ip for 15 days and euthanasia after this period; (e) subclinical hypothyroidism treated with thyroxine (T4 + HS): rats underwent partial thyroidectomy treated with T4 (dose 0, 8 ¼g/100g, ip) for 5 days and euthanasia after this period. After established periods, the animals will be anesthetized and blood collected for subsequent measurement of T3, T4, and TSH serum. Euthanasia will be performed by exsanguination and surgical removal of the heart with the animal under anesthesia. The ventricle will be removed, frozen in liquid nitrogen, and stored at -80°C and subsequently processed for the gene and protein expression of Mb and Cytb by Real-Time Polymerase Chain Reaction (qPCR) and western blot, respectively. The data from both the Real-Time PCR and densitometry results of the western blot will be analyzed in Excel, Microsoft Office, and the samples to be studied will be normalized by their corresponding controls. The data will be analyzed by analysis of variance (Way ANOVA) with post-test Student Newman Keuls. Differences will be considered significant for values of P <0.05. (AU)