Introduction: Neuropathic pain is a chronic pain caused by sensory neural system defects. This type of pain disrupts life because it is non-responsive to the common pain killers and takes a long time if repairs. Vitamin K2 by its antioxidant activity, inhibition of oxidative stress and inhibiting bradykinin and dynorphin effects, is expected to inhibits neuropathic hyperalgesia. Materials and Methods: This experimental study was performed using 42 male rats weighing 200-250 g. Neuropathic hyperalgesia was created by the Sciatic nerve closure model. Animals were randomly divided into 6 groups (n=7), positive control group, negative control group with sciatic nerve closure, chronic groups receiving peritoneal vitamin K2 at 25, 50, 100 mg / kg in 14 days post-surgery and sham group receiving (1% v/v DMSO) as vitamin K2 vehicle within 14 days after surgery, mechanical (pin prick) and thermal (hot plate) hyperalgesic tests on day zero (before surgery) and days 3, 7, 14, 21 and 28 after surgery were performed. Results: Chronic Intraperitoneal injection of vitamin K2 at the doses of 25, 50, and 100 mg/kg significantly reduced mechanical and thermal hyperalgesia on the days 3, 7, 14, 21 and 28 after surgery (p <0.05). The most effective dose was 100 mg/kg which reduced both thermal and mechanical hyperalgesia (p <0/01). Conclusion: Regarding the effects of oxidative stress reduction and inhibition of bradykinin and dynorphin, which is reported for vitamin K2, it is possible that the same mechanisms, inhibited the changes leading to the neuropathic hyperalgesia following nerve injury.

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