Evaluation of oxidative stress and antioxidant defense biomarkers in healthy and colic horses: correlation with type of colic and outcome

Background: Colic is a major cause of morbidity and mortality in horses, with oxidative stress implicated in its pathophysiology. Hypothesis/Objectives: Evaluate biomarkers (BIOs) of oxidative stress and antioxidant defense in healthy horses and those with non-strangulating colic (NSC) and strangulating colic (SC) and assess correlations with survival. Animals: Seventy-one adult horses: 10 healthy and 61 colic-affected (42 NSC, 19 SC) admitted to 3 veterinary teaching hospitals. Methods: Prospective, multicenter cohort study. Blood samples were collected at admission (T0) and up to 96 h post-admission. Biomarkers measured included arylesterase (AREase), paraoxonase (POase), lipid peroxidation (LPO), superoxide dismutase (SOD), butyrylcholinesterase, total antioxidant capacity (TAC), glutathione S-transferase (GST), and glutathione peroxidase (GPx). Data were analyzed using nonparametric statistics and generalized linear mixed models. Results: Compared with healthy horses, colic-affected horses had higher AREase (P = .01), GST (P = .001), and GPx (P = .001), and lower POase (P < .001) and TAC (P = .02). Survival was associated with higher AREase (coefficient [coef.] 106.65 kU/L; 95% confidence interval [CI], 24.70-188.60; P = .01), lower SOD (coef. -0.38 U/mL; 95%CI, -0.76 to -0.06; P = .03), and lower TAC (coef. -3.37 mu mol/mL; 95%CI, -5.49 to -1.25; P = .01). Colic type also influenced results, with NSC (vs SC) associated with lower LPO (coef. -1.24 malondialdehyde [MDA]/mu L; 95%CI, -2.81 to -0.32; P = .01), higher SOD (coef. 0.42; 95%CI, 0.03-0.81; P = .04), and higher TAC (coef. 1.21; 95%CI, 0.10-2.98; P = .04). Conclusions and clinical importance: Results emphasize the association between oxidative stress BIOs and colic in horses, suggesting that specific BIOs, particularly AREase, may have prognostic utility.