[Morphological observation of nerve fibers at different periods in full-thickness burn wound]

To observe the change in quantity and morphology of nerve fibers in different periods in granulation tissue in full-thickness burn wound.

The granulation tissue samples were harvested from 40 patients with full-thickness burn in our unit at 1st, 2nd, 3rd and 4th post burn week (PBW), 10 samples were obtained at each time point. Donor site tissues from 10 burn patients were used as normal control. Immunofluorescent staining technique with anti-neurofilament (NF) monoclonal antibody was employed to examine the expression of nerve fibers in granulation tissue and normal skin. The morphology of nerve fibers was observed with fluorescence microscope and laser scanning confocal microscope.

Fluorescence microscopy showed: nerve fibers were short and rare at 1 PBW, the ratio of nerve fibers positive area was (0.14 +/- 0.08)%. Nerve fibers increased slightly and were in single filament without branches, and the positive area ratio of nerve fibers (0.40 +/- 0.09)% was much lower than that of normal control [(0.62 +/- 0.12)%, P < 0.05]. Nerve fibers increased significantly and were arranged like a mesh with more branches and sproutings, and the positive area ratio of nerve fibers was (0.73 +/- 0.16)% at 3 PBW. The quantity of nerve fibers at 4 PBW was similar to that of 3 PBW, and the positive area ratio of nerve fibers was (0.66 +/- 0.13)%. Observations under LSCM: the nerve fibers were short at 1, 2 PBW; was irregular at 3 PBW, among them some were swollen and distorted, and fragmentation and vacuolation were observed. They became aggregated at 4PBW with less branches, similar to that at 3 PBW. The structures of nerve fibers in normal control were intact, without obvious pathological changes.

The change in quantity and morphology of nerve fibers in burn wound is related to the time of granulation tissue development.