Análise dos parâmetros bioquímicos de camundongos submetidos a diferentes períodos de jejum

Abstract

The fasting time preceding most biochemical assays aims to obtain a more reliable result, minimizing the chances of dosing an analyte at concentrations that do not represent the physiological values found in animal’s plasma or serum. The objective of this study was to analyze the plasma concentrations of various biochemical parameters in mice under different fasting periods. The experiment was done by dividing 30 Swiss male mice into 5 groups (n = 6), J4, J8, J12, J19, J24 (relative to fast for 4, 8, 12, 19 and 24 hours respectively). After the fasting period specified to each group, the animals were anesthetized and blood collection was performed by infra orbital plexus. After centrifugation, plasma was obtained and proceeded to the biochemical measurement of glucose, total cholesterol, triglycerides, albumin, total protein, urea, AST, ALT. The results were plotted in GraphPad Prism 5.0 software and analyzed statistically according to ANOVA test followed by Tukey post-test. The protocol was submitted to the Ethics Committee for Animal Research (CEPA) with the number 061/12. The results showed significant reduction in glucose levels in all groups compared to J4, it was higher (54.25%) in J19; cholesterol levels increased slightly in comparison to J4, which increase was 15,64% in J24; a significant increase of triglyceride levels in all groups from J12, which was higher (532.4%) in J24, and there was 100% increase in AST levels in J19 compared to J4; ALT levels have increased 114.44% in relation to J4. Prolonged fasting depletes the levels of plasma glucose, and then the body starts to use its lipid energy reserves to cover the deficit glucose. Concomitantly, the process of gluconeogenesis occurs in the liver, in part by transamination reactions of amino acids from skeletal muscle by ALT and AST. Thus, the fasting time affects variably the levels of biochemical parameters in mice, and optimal fasting time should be as short as possible to avoid suffering to animals.