Changes in Somatostatin-Like Immunoreactivity in the Sympathetic Neurons Projecting to the Prepyloric Area of the Porcine Stomach Induced by Selected Pathological Conditions

Abstract

The aim of the present study was to define changes in the expression of somatostatin (SOM) in the sympathetic perikarya innervating the porcine stomach prepyloric area during acetylsalicylic-acid-induced gastritis (ASA) and experimentally induced hyperacidity (HCL) and following partial stomach resection (RES). On day 1, the stomachs were injected with neuronal retrograde tracer Fast Blue (FB). Animals in the ASA group were given acetylsalicylic acid orally for 21 days. On the 22nd day after FB injection, partial stomach resection was performed in RES animals. On day 23, HCL animals were intragastrically given 5 ml/kg of body weight of a 0.25 M aqueous solution of hydrochloric acid. On day 28, all pigs were euthanized. Then, 14-μm thick cryostat sections of the coeliac-superior mesenteric ganglion (CSMG) complexes were processed for routine double-labelling immunofluorescence. All pathological conditions studied resulted in upregulation of SOM-like (SOM-LI) immunoreactivity (from 14.97 ± 1.57% in control group to 33.72 ± 4.39% in the ASA group, to 39.02 ± 3.65% in the RES group, and to 29.63 ± 0.85% in the HCL group). The present studies showed that altered expression of SOM occurs in sympathetic neurons supplying the prepyloric area of the porcine stomach during adaptation to various pathological insults.

Figure 1

Representative images of the CSMG neurons projecting to the prepyloric region of the porcine stomach. Fluorescent micrographs showing FB-labelled neurons (a, e, i, m) displaying immunoreactivity to somatostatin (SOM) and tyrosine hydroxylase (TH) in animals of control (b, c), ASA (f, g), RES (j, k), and HCL (n, o) groups (neurons are indicated with arrows). Photographs (d, h, l, and p) have been created by digital superimposition of three colour channels.

Figure 2

Representative images of the SOM-LI perikarya in the population of the CSMG neurons. Fluorescent micrographs showing SOM-LI neurons in the population of the CSMG neurons in animals of control (a), ASA (d), RES (g), and HCL (j) groups (neurons are indicated with arrows). Photographs (c, f, i, and l) have been created by digital superimposition of three colour channels.

Figure 3

Gastroscopic examination. The gastric mucosa without lesions before ASA-treatment (a) and before HCL infusion (c). Hyperaemia (arrowheads) and superficial erosion (arrow) caused by ASA-treatment (b) and hyperacidity (d).

Figure 4

Histopathological examination. Histopathological changes in the gastric mucosa induced by long-term ASA-supplementation: superficial erosion (arrows) (a), hyperaemia (arrows) (b, c), and proliferation of lymphatic cells (arrows) (d).