OBJECTIVETo observe the changes in the morphology and distribution of substance SP and calcitonin-gene related peptide nerves in the anterior pituitary of scalded rats.

METHODSThe rats inflicted 30% TBSA degree scalding of the back were employed as the model. The SP and CGRP peptide nerve fibres in the anterior pituitary were observed by immunohistochemistry staining during different postburn time points: 1, 2, 6, 10, 12, 24 and 72 postburn hours (PBHs). The areas of coverage of SP and CGRP nerve fibers were determined respectively in the anterior pituitaries by image analysis.

RESULTSThe morphology of the two peptide nerve fibers exhibited obvious changes under microscope. The numbers of SP and CGRP nerve fibers increased by 85.7% and 60.5%, respectively at 1 PBH when compared with those in control group. Moreover the varicosities and branches of the nerve fibers in scalded rats increased obviously at 1 PBH and decreased sharply at 2 PBH, bouncing back to near normal level at 24 PBH. reaching image analysis revealed that the changes in the areas of coverage of two peptide nerve fibers were correlated positively with each other. The basic trends of the changes were an increase at 1 PBH, a decrease thereafter, reaching the lowest level at 12 PBH with a rebound later.

CONCLUSIONThe morphology and distribution of SP and CGRP nerve fibers of anterior pituitary in scalded rats exhibited obvious change after injury. Therefore, they might be involved in the functional modulation of systemic stress.