Morphology of canine pancreas in electron microscopy following truncal and highly selective vagotomy.

The purpose of the study was evaluation of morphological changes in canine pancreas on days 30, 90 and 180 after truncal vagotomy (VT) and highly selective vagotomy (HSV). On the 30th day after VT in some cells zymogen granules and lysosomes were disintegrated, vacuolization was moderately expressed, and fibrosis was present in the exocrine part. On the 30th day after HSV the structure of the exocrine part showed no important changes, but in the endocrine part in about one-third of cells in the islets deformed nuclei and trinucleated cells were found, along with changes of mitochondrial structure. beta cells contained very numerous insulin-containing granules. On the 90th day some changes observed on the 30th day after VT or HSV were no longer seen. On the 180th day after HSV the EM changes were negligible, less intense than after VT. The electron microscopic changes after VT and HSV were most pronounced early after the operation, particularly after VT. In later stages of the experiment a part of the changes regressed, but then more structural changes were seen after VT than after HSV.