Anti-inflammatory and antioxidative effects of fluoxetine on neuropathic pain responses in a Rat model of chronic constriction injury

One of the most important side effects after neural injury is neuropathic pain. Increasing levels of inflammatory cytokines and oxidative stress play an important role in causing pain. Fluoxetine is one of the most important drugs used in the treatment of depression, which has been shown to have anti-inflammatory and anti-oxidative effects. In this study, we investigated the anti-inflammatory and antioxidant effects of fluoxetine in a Rat model of chronic constriction injury (CCI).

40 male Wistar rats were used in this study (230-250 g, n=10). Animals randomly individual in 4 groups such as: Sham, CCI, CCI + Fluoxetine (2 mg/kg, IP injection, for 14 days) and CCI + Fluoxetine (5 mg/kg, IP injection, for 14 days). Rats were tested behavioural tests (heat hyperalgesia, heat and mechanical Allodynia) on the days of 1, 7 and 14 after induced CCI. After 14 days, spinal cord was collected to measure tissue concentration of anti-inflammatory and antioxidative enzymes including tumor necrosis factor-α (TNF- α) interleukin-6 (IL-6), malonedialdehyde (MDA) and superoxide (SOD).

The results of behavioral tests revealed that administration of fluoxetine reduced the symptoms of neuropathic pain. Fluoxetine administration also decreased levels of TNFα, IL-6 and MDA and increased SOD levels.

Findings of this study showed that that fluoxetine has protective effects in an experimental model of neropathic pain and this effect might be mediated via its anti-inflammatory and antioxidant effects.