Avaliação de biomarcadores fisiológicos em ratos Wistar tratados com diferentes regimes de redução de Prednisona

Abstract

Prednisone is a glucocorticoid synthetic to cortisol, being the most frequently used in clinical practice due to its anti-inflammatory and immunosuppressive action. Even in the face of its benefits, its use should be done with caution as it is not free of adverse effects such as changes in the metabolism, which may suffer variations concerning the dose and duration of treatment. Currently, there is no consensus on the best way to discontinue treatment, due to existing limitations in human research, it is of great interest to study the different prednisone withdrawal schemes in an animal model. Thus, this study aims to evaluate physiological and immunological biomarkers in Wistar rats submitted to different prednisone reduction regimens. For this, 28 male Wistar rats were used, which were divided into four groups and submitted to a daily treatment of Prednisone and/or its vehicle (Syrspend®) for 28 days. The PRED group (n = 7) received prednisone 5mg/kg for 28 days; RET (n = 7) received prednisone 5mg/Kg for 14 days and then the treatment was replaced by Syrspend®; RED+RET 1 (n = 7) received prednisone 5mg/Kg for 14 days, from the 15th the dose was reduced to 2.5mg/Kg and on the 21st day it was replaced by Syrspend®; RED+RET 2 (n = 7) received prednisone 5mg/Kg for 14 days and on the 15th day a 50% dose decrease was started every three days and on the 27th day the dose was replaced by Syrspend®. Body weight, water and food consumption in 24 hours were evaluated weekly. The total and differential leukogram was performed on days 0, 14 and 28. At the end of the study, the rats were euthanized so that the organs were surgically collected to estimate their relative weight. The results were considered statistically significant when p<0.05. There were no statistical differences between the experimental groups regarding the total and differential leukogram, relative organ weight, and body weight. Regarding water consumption, there was a decrease on day 14 of the RED+RET 1 group compared to the RED group, the RET and RED+RET 2 groups on day 28 had increased consumption when compared to day 7. on day 28 the RET and RED+RET 2 groups had an increase in consumption compared to day 0. On day 28, all experimental groups had an increase in consumption when compared to days 7 and 14, in groups RET, RED+RET 1 and RED+RET 2, on day 28 there was an increase in food consumption compared to day 21. Therefore, it is concluded that the RED+RET 1 group had fewer alterations, but based only on the results of the analyzed parameters, it is not possible to state which is the best Prednisone reduction regimen.