Innervation of recurrent aphthous ulcers.

Abstract

Specimens from nonkeratinized oral mucosa were obtained from diseased and clinically healthy mucosa from 7 patients with minor recurrent aphthous ulcers. The innervation of the specimens was visualized using antibodies to neuron-specific intermediate cytoskeletal neurofilament fiber, the cytoplasmic protein gene product 9.5 and a 38 kDa integral membrane protein of synaptic vesicles applied in avidin-biotin-peroxidase staining. Mapping with these 3 antibodies revealed dense and basically similar pattern of innervation in the specimens of the clinically healthy oral mucosa. In recurrent aphthous ulcers, all 3 general markers disclosed peripheral nerve fibers also in the lesions, apart from the necrotic area, among the inflammatory cells without signs of retraction from the diseased area. Synaptophysin staining suggested that these peripheral nerve fibers in the inflammatory areas still contained synaptic vesicles. Accordingly, they were shown to contain substance P and calcitonin gene-related peptide, which are known to be released upon stimulation of the nerve and can exert potent paracrine actions, possibly on the local inflammatory cells as suggested by a close spatial relationship between neuropeptide-containing nerves and inflammatory cells.