Effects of running and swimming on pain relief in male rats with type 2 diabetes-induced peripheral neuropathy

Abstract Type 2 diabetes (T2D) is the most prevalent type of diabetes and can lead to painful peripheral neuropathy (PN). Exercise can alleviate PN-related pain, but the comparative effects of running and swimming remain underexplored. Methods: Forty-eight male Wistar rats were randomly divided into: control (C), swimming (Sw), running (Run), diabetes (D), D-Sw, and D-Run. T2D was induced by high-fat-diet (60%) and streptozotocin (35 mg/kg). Rats underwent individualised swimming or running (8-weeks, 5 days/week, 60 min/day). Body weight gain (BWG), FBG, HOMA-IR, lipid profiles, and neuropathy tests: PWT (paw-withdrawal-threshold), LT (licking-time), FN (flinching-number), MSCP (cold-plate-mean-speed), EI (escape-index), CPE (cold-plate-entries) were measured. Data analysed using repeated measures ANOVA and equivalent non-parametric tests ( ). Results: Diabetes worsened BWG ( ; 95% CI: −71.96 to −8.76; −14.05 ± 6.47% from baseline), FBG (day-86: ; 95% CI: 383.53 to 464.06; −18.5 ± 5.18% from baseline), insulin ( ; 95% CI: 2.68 to 3.23), HOMA-IR ( ; 95% CI: 2.53 to 3.68), lipid profiles ( ), right PWT (day-84: mean ± SEM: 10.60 ± 1.16; ), LT (day-56: 2.10 ± 0.48; ), and (day-84: 5.78 ± 0.78; ). FN (day-56: 2.64 ± 0.36; ) and (day-84: 5.24 ± 0.79; ) differed. Final MSCP (7.88 ± 0.88; ), EI (3.83 ± 0.68; ), and CPE (3.40 ± 0.50; ) were worsened. Similarly, D-Sw improved FBG ( ; 95% CI: 137.63 to 157.16; −69.87 ± 3.13% from baseline), insulin ( ; 95% CI = 2.68 to 3.23), HOMA-IR ( , 95% CI = 0.76 to 0.92), TG ( ; 95% CI: 59.63 to 82.76), VLDL (95% CI = 11.92 to 16.55), final PWT (51.00 ± 9.00, ), LT (2.10 ± 0.48; ), MSCP (4.44 ± 0.38, ), EI (1.37 ± 0.12, ), and CEP (9.00 ± 1.22, ). The analyses revealed large effect sizes in BWG (η 2 = 0.73), FBG (η 2 = 0.96), insulin (η 2 = 0.86), HOMA-IR (η 2 = 0.73), and TCH (η 2 = 0.82), TG (η 2 = 0.89), HDL (η 2 = 0.84), LDL (η 2 = 0.78), and VLDL (η 2 = 0.89). Neuropathy behavioural metrics showed varying effect sizes: PWT (Kendall’s W = 0.256), LT (W = 0.29), FN (W = 0.39), MSCP (W 0.05), EI (W = 0.16), and CPE (W = 0.23). Conclusion: These findings demonstrated that both modalities were effective, but swimming seemed better in alleviating T2D-related PN pain.