Structural features of ghrelin-producing endocrine cells and their reactive changes after experimental stress
The work is devoted to the analysis of reactive changes in ghrelin-producing endocrine cells (HPEC) in the main areas of production of this regulatory peptide - in the stomach and hypothalamus during modeling of psycho-emotional stress and after replacement therapy. Reactive HPECs in experimental post stress disorder models have not previously been specifically studied. Meanwhile, the practice of modeling stress to establish the effectiveness of therapeutic interventions suggests the feasibility of obtaining new and informative criteria for assessing the degree of its impairment and therapeutic effect. The purpose of the study was to establish quantitative features and reactive changes in the GPEC of the stomach and hypothalamus in a model of psychogenic stress. Material and methods. We studied paraffin sections of the hypothalamus and the mucous membrane of the cardial part of the stomach in four groups of mature male rats. The first group (n=5) consisted of intact rats. The rest of the animals were subjected to a single emotional stress. In the nostrils of animals of two experimental groups (n=5 in each), 12 hours after stress, 20 μg of a solution of ghrelin (GHRL, Tocris, Gr. Brit.) and a peptide antagonist of ghrelin receptors ([D-Lys3]-GHRP-6, Tocris, Gr. Brit.). On the 4th day, animals were selected for the main control group (n=5). The number of endocrinocytes in the lateral part of the nuclei of the arcuate complex was counted over an area of 0,01 mm<sup>2</sup>, in the fundic glands of the stomach - over an area of 0,015 mm<sup>2</sup>; the area of endocrinocyte bodies was determined using the Imagescope program (Electronic analysis, Russia). The median, upper and lower quartiles, and the significance of their differences in the compared groups (using the nonparametric Mann-Whitney test) were measured using the GraphPad PRISM 6.0 program (GraphPad Software, USA). Differences were considered significant at p<0,01. Results. During a short-term experience of psychogenic stress, the number of viable gastric and hypothalamic HPECs decreased by 2,5 and 3,8 times (respectively; p<0.001), and their body area decreased by 1,5 and 1,6 times (p<0,001). Pharmacological methods of correction did not significantly affect these parameters of HPEC (p>0,05).