17beta estradiol ameliorates neuroinflammation driven neuropathic pain in chronic constriction injury – induced peripheral neuropathy in rats

Abstract

Background. Accumulating evidence illustrates that peripheral nerve injuries activate glial components of the peripheral and central cellular circuitry which contributes to neuroinflammation and neuropathic pain. Epidemiological surveys suggest that for women the prevalence of pain increases with age with more frequent pain than men. Recently, several studies have found that pain generation, transmission and modulation are under hormonal regulation. To this end, 17beta oestradiol was used to investigate the modulatory actions on nociceptive thresholds in neuroinflammation driven neuropathic pain conditions. Methods. Adult female Wistar rats were divided into four groups: Ovariectomised neuropathic untreated and neuropathic 17 beta oestradiol treated groups. sham operated and intact control groups. Results. In treated rats, the results validate an anti-inflammatory action of 17 beta oestradiol against chronic constriction injury (CCI) induced neuropathic pain by attenuating complement C3 fractions and anti-neutrophil cytoplasmic auto-antibodies (ANCAs) intensity plasma level, an anti-nociceptive action by attenuating ipsilateral, contralateral allodynia and hyperalgesia developed in treated animals after chronic con-striction injury and at the last day of treatment by increasing the tail flick latency at the last day of treatment. Conclusions. We conclude that 17beta oestradiol might exhibit beneficial effects on peripheral nerve injury consequences.

Keywords

• bilateral ovariectomy
• chronic constriction injury
• allodynia
• hyperalgesia
• up and down order method
• 17beta oestradiol therapy