Application of serum and urinary electrophoresis as an aid tool for evaluating dogs at different stages of chronic kidney disease

Chronic kidney disease (CKD) is a common, progressive, and irreversible disease in dogs. Inflammation and proteinuria are related to the process of CKD progression. The search for early markers and indicators of the degree and location of renal inflammation to aid in diagnosis and prognosis is very important. The aim of this study was to evaluate the applicability of serum and urinary electrophoresis as an aid tool in the diagnosis of dogs with chronic kidney disease according to the stage of CKD (IRIS 2019b). For this, 27 canine patients from routine clinical practice were evaluated and divided into five groups: C (control), G1 (CKD—stage 1), G2 (CKD—stage 2), G3 (CKD—stage 3), and G4 (CKD—stage 4). Samples were evaluated by serum and urine biochemistry, urinalysis, and serum and urine polyacrylamide gel electrophoresis (SDS-PAGE). In serum electrophoresis, difference was observed between the C and the CKD group, with a decrease in 40.76 (P = 0.017), 33.96 (P = 0.025), and 25.79 kDa (P = 0.049) serum proteins caused by the loss of protein in the urine in dogs affected with CKD. The urinary electrophoresis showed an important difference between groups in the evaluation of the lesion pattern, and in the glomerular and tubular lesion score, there was a difference in the glomerular lesion score of C in relation to G2 (P = 0.007), G3 (P = 0.016), and G4 (P = 0.000). Regarding the tubular lesion score, there was a difference between C and G2 (P = 0.029), G3 (P = 0.000), and G4 (P = 0.000), and between G4 and G2 (P = 0.037), with a higher score in G4. Based on these results, the application of urinary electrophoresis can be indicated as an aid tool in the diagnosis of CKD, proving useful in the evaluation of the site and the severity of renal disease.