Serum and synovial fluid protein electrophoretic profiles reveal systemic-articular inflammatory associations in goats with SRLV-associated arthritis

Small ruminant lentiviruses (SRLV) are chronic progressive infections associated with persistent inflammation, with arthritis representing one of the main clinical manifestations in goats. Despite the immunomediated nature of SRLV-associated joint disease, integrated evaluations of systemic and local protein alterations remain limited. This cross-sectional observational study aimed to characterize serum and synovial fluid protein electrophoretic profiles in goats naturally infected with SRLV presenting chronic arthritis and to investigate associations with clinical joint parameters. Fifty adult lactating Saanen goats were allocated into two groups: SRLV-positive goats with chronic arthritis (n = 25) and SRLV-negative healthy controls (n = 25). Clinical evaluation included the clinical articular index (CAI), carpal circumference, and estimated carpal volume, followed by blood and synovial fluid collection. Protein fractions were determined by polyacrylamide gel electrophoresis (PAGE), quantifying albumin, α1-, α2-, β1-, β2-, and γ-globulin fractions. SRLV-positive goats showed significant increases (p < 0.05) in serum α1-, α2-, β1-, and β2-globulins, while all synovial protein fractions were significantly altered compared to controls. The most pronounced synovial alteration was observed in the γ-globulin fraction, which was approximately 3.1-fold higher in infected goats. Moderate positive correlations were observed between serum α2-globulin and synovial γ-globulin (r = 0.56; p < 0.01), as well as between synovial β1-, α1-, and γ-globulins and clinical indicators of joint disease severity (r = 0.52–0.64; p < 0.05). These findings indicate that SRLV-associated arthritis in goats is characterized by a systemic-articular inflammatory axis involving sustained acute-phase activation and marked local humoral immune activity. Serum and synovial fluid protein electrophoresis may provide a useful complementary approach for inflammatory profiling and for identifying protein fractions with potential as candidate biomarkers of articular disease activity in SRLV-infected goats.