Histological and functional aspects of young rats, adult and elderly: a comparative study

Abstract

Aging is recognized as a progressive, gradual, and variable process characterized by increasing loss of functional reserve, and consequences of morphological, physiological, biochemical, and psychological alterations. This comparative study was proposed with the aim of checking the histological and functional muscle and bone tissue in young, adult, and elderly rats. Upon approval of this study in the Ethics Committee on Animal Experiments of the Faculty of Dentistry of Araraquara - UNESP, will be used 35 rats (Rattus norvegicus albinos, Holtzman) with body weight ranging from 120g to 650g. The animals will be divided into three groups, 10 older animals with 120 days of age (4 months), 10 adult animals with 180 days of age (6 months), and 15 aged animals with 540 days of age (18 months). After blood collection will be carried out blood tests (cholesterol, triglycerides, blood glucose, serum calcium, urea, and creatinine), the analysis of muscle mass (weight) and mass of the femur (the left gastrocnemius muscle is fixed at 10% buffered formalin for 72 hours and processed for paraffin embedding, stained with HE and Masson's trichrome for histological analysis), analysis of bone calcium, analyzing the amount of calcium per gram of ash and protein analysis of the gastrocnemius muscle. From each animal, 200g of the gastrocnemius muscle will be extracted and digested in perchloric acid. The digestion product is then centrifuged and the supernatant is diluted and analyzed for protein content. For knowledge of the differences between the groups will be used analysis of variance - ANOVA - test of multiple comparisons followed by Bonferroni.(AU)