Therapeutic evaluation of oral Spirulina platensis on glycemic control and pain modulation in streptozotocin-induced diabetic neuropathic Long-Evans rats

Open Access

Abstract

Background: Diabetic neuropathy, a major chronic complication of diabetes, results from hyperglycemia, oxidative stress, and neuroinflammation. Spirulina platensis, a nutrient-rich cyanobacterium, has antioxidant, anti-inflammatory, and potential blood sugar-lowering effects. This study evaluated Spirulina's effects on blood sugar and pain behavior in STZ-induced diabetic rats. Methods & Materials: Sixty Long Evans rats were allocated into six groups: control, Spirulina-treated, and sodium salicylate–treated for both non-diabetic and diabetic conditions. Diabetes was induced with STZ (60 mg/kg). Spirulina was given orally at 500 mg/kg/day for a month. Blood glucose and body weight were measured at baseline and week four. Nociceptive behavior was assessed using the formalin test, covering neurogenic (0–10 min) and inflammatory (15–60 min) phases. Results: Untreated diabetic rats developed marked hyperglycemia by week four (265.2 ± 28.13 mg/dL). Spirulina treatment significantly reduced fasting glucose (148.7 ± 25.47 mg/dL; P < 0.01), while non-diabetic groups remained normoglycemic. Body weight improved modestly in Spirulina-treated diabetic rats (200.8 ± 4.0 g to 212.9 ± 4.1 g), compared with minimal gains in diabetic controls. Formalin-induced nociceptive scores were highest in diabetic rats (1st phase: 2.18 ± 0.08; 2nd phase: 2.03 ± 0.07). Spirulina significantly attenuated nociception in both phases (1.67 ± 0.06 and 1.53 ± 0.05; P < 0.01), indicating both anti-neurogenic and anti-inflammatory effects. Sodium salicylate reduced pain predominantly in the late phase. Conclusion: Spirulina platensis exhibits strong antihyperglycemic, metabolic, and antinociceptive effects in STZ-induced diabetic rats. Its combined antioxidant, anti-inflammatory, and insulin-modulating activities suggest promising therapeutic potential for managing diabetic neuropathy and associated metabolic disturbances. Further mechanistic and clinical studies are warranted to validate its translational applicability.