Expression of aquaporin 2 following facial nerve crush in rats.

CONCLUSION: We demonstrated an early increase in aquaporin 2 (AQP2) expression in a motor nerve (extratemporal facial nerve, FN) following acute peripheral compression (crush), concomitant to effective development of motor dysfunction (facial palsy). The early increase in AQP2 expression that occurred concomitantly with the appearance of a deficit in a peripheral motor nerve suggests that this protein is involved in the physiological events associated with post-injury edema, similar to the already demonstrated behavior of AQP4 in the central nervous system (CNS). OBJECTIVE: The aim of this study was to assess the expression of AQP2 in the FN of rats up to 7 days after crush. METHODS: The extratemporal trunk of the right FN of rats was subjected to mechanical crush, and the expression of AQP2 in the affected (right) and non-affected (left) FN was measured by means of western blotting at days 1, 3, and 7 after injury. Behavioral analysis of the development of facial palsy was also performed over the same time period. RESULTS: Increased expression of AQP2 was shown in the affected FN compared with its corresponding control at day 1 after compression, simultaneously with the appearance of facial palsy.