Curcumin liposomal nanoparticles provide superior neuroprotection by attenuating neuropathic pain, neuroinflammation and anxiety in chronic sciatic nerve injury in rats.

Abstract

Background: Chronic constriction injury (CCI) of the sciatic nerve induces neuropathic pain, inflammation, oxidative stress and neurodegenerative changes, impairing sensory and emotional function. While curcumin is well recognised for its anti-inflammatory and neuroprotective properties, its therapeutic use is limited by poor bioavailability. Curcumin liposomal nanoparticles (CLNs) offer improved delivery and stability.

Methods: Male rats (n = 24) were randomly assigned to control, CCI, CCI + curcumin (60 mg/kg) and CCI + CLNs (40 mg/kg) groups. CCI was induced through sciatic nerve ligation, followed by 14 days of treatment. Behavioural assessments included thermal and mechanical pain sensitivity, anxiety-like behaviour (elevated plus maze), and sciatic nerve function (SFI). Serum inflammatory (tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6)) and oxidative stress markers (malondialdehyde (MDA), total antioxidant capacity (TAC), superoxide dismutase (SOD) and reduced glutathione (GSH)) were measured, alongside histological analysis.

Results: Compared to curcumin, CLNs showed superior efficacy in improving pain thresholds, anxiety-like behaviours and SFI scores. CLNs significantly lowered TNF-α and IL-6 levels and enhanced SOD activity, with no intergroup differences in MDA, TAC or GSH. Histology confirmed nerve regeneration and reduced neurodegeneration.

Conclusions: CLNs effectively alleviated neuropathic pain, reduced neuroinflammation and improved functional recovery after sciatic nerve injury, while mitigating anxiety-like behaviours.