Regeneration of nerve fibres in the maxillary sinus mucosa after experimental surgery. An immunocytochemical double-labelling study in the rabbit.

Nerve fibre regeneration in the maxillary sinus mucosa after surgery was studied in 10 New Zealand White rabbits. Four and 8 weeks following unilateral removal of the mucosa, the animals were fixed by perfusion, and the nose-sinus complexes were frozen and cut on a cryostat equipped with a tungsten-hardened knife. A double-labelling immunocytochemical procedure was developed with commercially available antibodies to protein gene product (PGP) 9.5 and tyrosine hydroxylase (TH) or neuropeptide Y (NPY). The study revealed that the maxillary sinus mucosa in rabbit is reinnervated at 4 and 8 weeks postoperatively. Furthermore, the regenerated lamina propria showed increased TH immunoreactivity (TH-IR) and NPY-IR, compared with the contralateral, non-operated side. Many of the fibres were seen in close proximity to newly formed vessels. These findings add further to the explanation of the altered vasoreactivity found earlier in regenerated sinus mucosa 1 month after surgery. This study also showed that demineralization of the nose-sinus complexes is not necessary if a hardened metal knife is used.