Effects of saffron [Crocus sativus L.] stigma extract and its active constituent crocin on neuropathic pain responses in a rat model of chronic constriction injury

ABSTRACT

This study was designed to investigate the therapeutic effects of saffron [Crocus Sativus L] and its main constituent crocin on neuropathic pain behavioral responses induced by chronic constriction injury [CCI] in rats. Adult male Wistar rats [200 to 250 g] were randomly assigned into 5 groups Sham + saline, CCI + saline, CCI+ saffron [30 mg/kg], CCI +crocin [15 mg/kg] and CCI + crocin [30 mg/kg]. CCI was induced by applying 4 loose ligatures around the sciatic nerve. Two weeks after nerve lesion, injections of saline, saffron or crocin were started and continued until 26th day post-surgery. Pain behavioral responses including mechanical allodynia [von Frey filament testing] and thermal hyperalgesia were measured in 14, 17, 20, 23, 26, and 40th days after CCI. CCI significantly increased pain behavioral responses. Saffron and crocin [30 mg/kg] decreased thermal hyperalgesia and mechanical allodynia on day 26, and this effect continued until the day 40. Crocin at lower dose [15 mg/kg] was ineffective. These findings indicate that treatment of saffron and crocin after CCI may have a therapeutic effect against neuropathic pain, suggesting that these substances may offer new strategies for the treatment of this highly debilitating condition