Parietal cell regeneration in rat gastric mucosal wounds a quantitative light and electron microscopical study

Abstract: The aims of the study were to obtain a method with which it would be possible to produce standardized wounds in the gastric mucosa, and to follow the regeneration of the acid producing parietal cells in those lesions during different experimental conditions. Quantitative methods applied to light and electron microscopy were used.Wounds were cauterized in the corpus mucosa in Sprague-Dawley rats and in addition, pyloroplasty, truncal vagotomy with pyloroplasty or ant- rectoiriy were performed. Other groups of rats with wounds were given long-term treatment with pentagastrin or cimetidine. Stimulation tests were carried out in two groups of wound operated rats.After different periods of time the animals were perfusion fixed and specimens from the wounds and normal mucosa beside the wounds were pre­pared for light and electron microscopy. By means of stereological techniques, different mucosal and cellular structures were then measur­ed.Parietal cells were found in 90 days old wounds. At this stage they were immature with large nuclei and few specialized cell organelles. In spite of this appearance they were able to respond morphologically to stimulation and to secrete acid. With further healing the morphology of the parietal cells became normal, but their volume fraction in the mucosa remained subnormal. The fraction of mucosa occupied by epithel­ial cells also stayed lower than normal.Pyloroplasty resulted in decreased cell and nuclear size of both normal and regenerating parietal cells. In the latter, there was also a de­crease in the mitochondrial volume density. If a truncal vagotomy was added to the pyloroplasty these changes disappeared and, in addition, an increase in parietal cell volume density was noticed in the normal mucosa.Antrectorny produced smaller parietal cells, and their maturation was delayed. Furthermore, mucosal thickness decreased. If pentagastrin was given to rats with wounds an increase in the number of parietal cells was noted, but maturation and morphology remained unaffected.Cimetidine treatment did not affect the parietal cell volume density in wounds or normal mucosa. However, a large increase in the secretory surface density was noticed when the effect of the last dose had ceas­ed.