Methods: Neuroma-in-continuity specimens were obtained from patients undergoing surgical repair of a damaged lingual nerve. The specimens were categorised pre-operatively according to the presence or absence of dysaesthesia, and visual analogue scales (VAS) were used to record the degree of pain, tingling and discomfort. Indirect immunofluorescence using antibodies raised against S-100 (a Schwann cell marker) and P2X7 was employed to quantify the percentage area of S-100 positive cells that also expressed P2X7.
Results: The results demonstrated that P2X7 is expressed in Schwann cells of lingual nerve neuromas. No significant difference was found between the level of P2X7 expression in patients with or without symptoms of dysaesthesia. Furthermore, no relationship was observed between P2X7 expression and the VAS scores for pain, tingling or discomfort. There was also no correlation between P2X7 expression and the time after the initial injury that the specimen was obtained.
Conclusion: These data show that P2X7 is expressed in human lingual nerve neuromas from patients with or without dysaesthesia. It therefore appears that the level of expression of P2X7 at the injury site does not play a principal role in the development of neuropathic pain after lingual nerve injury.