Morphological and morphometric indicators of structural components of the exocrine part of the pancreas after withdrawal of administration of monosodium glutamate to rats

The aim of the study was to determine the morphological and morphometric features of structural changes in the components of the exocrine part of the pancreas of male rats after withdrawal of the food additive sodium glutamate and their transfer to a normal diet. Materials and methods. 4 series of experiments were conducted. The 1st series – male rats were given 70 mg/kg of sodium glutamate daily for 8 weeks to enhance their taste; the 2nd series – rats were transferred to a standard diet 8 weeks after the use of monosodium glutamate and withdrawn from the experiment after 8 weeks (at week 16); the 3rd series – control group rats up to 8 weeks, the 4th series – control rats up to 16 weeks of the experiment. The pancreas was examined morphologically with morphometric analysis after the rats were withdrawn from the experiment, the material was paraffin-embedded and sections were made, stained with hematoxylin and eosin and azan. Results. In the 1st and 2nd series of the experiment, atrophic and degenerative changes of the acini were preserved, which were discomposed due to edema of the organ, and had small sizes. Connective tissue and areas of adipose tissue, diffuse and focal infiltrates were visualized between the lobules and around the lobular ducts. The ducts were dilated. As in the 1st series, there was edema of the organ parenchyma, vessel walls and ducts with fluid leakage into the intercalated spaces, and exocrinocyte apoptosis. The morphometric study of the exocrine part of the pancreas revealed that the average size of acini was statistically significantly reduced in the 1st and 2nd experimental series by 1.4 and 1.6 times, and the area by 1.2 and 1.5 times compared to control animals of the 3rd and 4th series. In the 1st and 2nd series, acini ranging in size from 71 μm to 90 μm prevailed, accounting for 38 % and 34 %, respectively, in the 1st and 2nd control series – 91–100 μm (46 % and 42 %) and from 111 μm to 149 μm (36 % and 38 %), respectively. In the study of the number of cells in acini in the 1st series, exocrinocytes were present in the amount of 5.52 ± 0.58 vs. control 8.05 ± 0.32 (p < 0.001), in the 2nd series – 5.24 ± 0.47 vs. control 7.33 ± 0.43 (p < 0.001) The area of exocrinocytes in the 2nd series 61.95 ± 1.91 μm2 vs. 78.99 ± 0.98 μm2 (p < 0.05) were reduced. The diameter of the insertional, intra-lobular and inter-lobular ducts was enlarged. Conclusions. After 8 weeks of feeding rats with monosodium glutamate and after its withdrawal and transfer of rats to the standard diet of the rat vivarium in the next 8 weeks, no improvement in the state of the pancreas was recorded, which was confirmed by morphological and morphometric studies.