Ameliorative potential of Vernonia cinerea on chronic constriction injury of sciatic nerve induced neuropathic pain in rats.

Venkata R.K Thiagarajan,Palanichamy Shanmugam,Arunachalam Muthuraman,Uma M Krishnan

doi:10.1590/0001-3765201420130404

Abstract

The aim of the present study is to investigate the ameliorative potential of ethanolic extract of whole plant of Vernonia cinerea in the chronic constriction injury (CCI) of sciatic nerve induced neuropathic pain in rats. Behavioral parameters such as a hot plate, acetone drop, paw pressure, Von Frey hair and tail immersion tests were performed to assess the degree of thermal, chemical and mechanical hyperalgesia and allodynia. Biochemical changes in sciatic nerve tissue were ruled out by estimating thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) and total calcium levels. Ethanolic extract of Vernonia cinerea and pregabalin were administered for 14 consecutive days starting from the day of surgery. CCI of sciatic nerve has been shown to induce significant changes in behavioral, biochemical and histopathological assessments when compared to the sham control group. Vernonia cinerea attenuated in a dose dependent manner the above pathological changes induced by CCI of the sciatic nerve, which is similar to attenuation of the pregabalin pretreated group. The ameliorating effect of ethanolic extract of Vernonia cinerea against CCI of sciatic nerve induced neuropathic pain may be due to the presence of flavonoids and this effect is attributed to anti-oxidative, neuroprotective and calcium channel modulator actions of these compounds.

Highlights

Pain is initiated or caused by a primary lesion or dysfunction in the peripheral nervous system
Chronic constriction injury of the sciatic nerve is the common model for the evaluation of anti-neuralgic agents and CCI is clinically resemble to Complex Regional Pain Syndrome (CRPS) (Kramer et al 2009, Nagler 2010, Muthuraman et al 2008b)
Chronic constriction injury (CCI) of sciatic nerve resulted in significant development of noxious thermal hyperalgesia, indicated by decrease in left hind paw withdrawal threshold, after 3rd day of surgery as compared to sham control

Summary

Introduction

Pain is initiated or caused by a primary lesion or dysfunction in the peripheral nervous system. AIDS, diabetes, leprosy, multiple sclerosis, and stroke are associated with neuropathic pain. Traumatic injury due to lumbar disc syndrome, traumatic spinal cord and brain injury and occu pational nerve entrapment (i.e., computer typing work) injury are associated with neuropathic pain (Alston and Pechon 2005, Koltzenburg and Scadding 2001). Chronic constriction injury of the sciatic nerve is the common model for the evaluation of anti-neuralgic agents and CCI is clinically resemble to Complex Regional Pain Syndrome (CRPS) (Kramer et al 2009, Nagler 2010, Muthuraman et al 2008b). Adverse effects have been reported for these medicaments which limit their full clinical exploitation in the management of painful neuropathy (Hammersla and Kapustin 2012). Pharmacotherapy requires newer drug molecules from alternative medicine for effective management of neuropathy in CRPS

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