THE MORPHOLOGICAL CHARACTERISTICS OF MOUSE HAIR FOLLICLES DURING RADIATION DAMAGE

The epidermis and its derivatives, including hair follicles, as highly radiosensitive structures, serve as markers of the course of reparative histogenesis, which allows assessing the degree of tissue damage and their regenerative potential. The aim of the work was to conduct a comparative morphological analysis of reactive changes in the hair follicles of mouse skin in various experimental models. The object of the study was white outbred male mice aged 12 weeks and weighing 25-30 g. The animals were divided into two experimental groups corresponding to different irradiation models. Mice of the first group (n=20) were irradiated once with an absorbed dose of 14 Gray. Animals of the second group (n=20) were repeatedly exposed to X-ray irradiation of 1 Gray for 30 days, followed by a 20-day period without irradiation (18 Gray in total). Skin fragments taken on the 25th and 50th days were fixed in 10% buffered neutral formalin solution and processed according to the standard method for light microscopy. To count the number of hair follicles per unit area, the method for determining the degree of skin damage was adapted taking into account the phases of mouse hair growth. Visually, skin damage in all experimental animals is characterized by varying degrees of hyperemia and hair loss. In the animals of the first experimental model, significant disorganization of epidermal cells and hair follicles is detected. The number of hair follicles decreases by 33.1% compared to the initial value. Epithelial cells of the outer and inner root sheaths are deformed, the cells of the epithelial matrix of the hair are almost not visualized. The degree of damage to hair follicles is 100%. The morphological picture of the skin in mice of the second experimental group is characterized by less pronounced changes, the shape of the keratinocytes of the epidermis and hair follicles is preserved, the degree of one type histogenesis cells heteromorphy expression is reduced. The number of follicles decreases by 24.3% compared to the initial values, and the degree of their damage is 37.8%. The conducted study confirms the primary lesion of the most radiosensitive tissue elements of the skin with the further development of its complex damage. The study of changes in hair follicles showed the clarity and accessibility of assessing the degree of expression of reactive changes in the epithelial structures of the skin.

1. Danilov RK. Ranevoy protsess: gistogeneticheskie osnovy. Sankt-Peterburg: VMedA im. S.M. Kirova; 2008.– 219s. In Russian

2. Jang WH, Shim S, Wang T et al. In vivo characterization of early-stage radiation skin injury in a mouse model by two-photon microscopy. Sci Rep.2016;6:1-9. https://doi.org/10.1038/srep19216

3. Pryakhin EA, Tryapitsyna GA, Shaposhnikova IA i dr. Vliyanie liposomal'nykh preparatov, soderzhashchikh rekombinantnye belki cheloveka al'fa-fetoprotein i granulotsitarny koloniestimuliruyushchiy faktor, na techenie luchevogo ozhoga kozhi IIIA stepeni u myshey. Radiatsionnaya biologiya. Radioekologiya. 2019;59(2):205-213. In Russian. https://doi.org/10.1134/S0869803119020115

4. Deev RV, Eremin PS, Chekmareva IA i dr. Strukturnye i ul'trastrukturnye osobennosti rannego povrezhdeniya tkaney kozhi pri mestnom luchevom vozdeystvii v vysokoy doze. Klin. eksp. morfologiya. 2021;10(3):55-64. In Russian. https://doi.org/10.31088/CEM2021.10.3.55-64

5. Gushchin YaA, Kovaleva MA. Sravnitel'naya morfologiya kozhi cheloveka i laboratornykh zhivotnykh (kratkoe soobshchenie). Laboratornye zhivotnye dlya nauchnykh issledovany. 2029;2:6. In Russian. https://doi.org/10.29296/2618723X-2019-02-06

6. European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes (18 March 1986). URL: http://www.worldlii.org/int/other/treaties/COETSER/1986/1.html

7. Kolchanova GM, Liberman AN, Bronshteyn IE i dr. Sposob opredeleniya chisla radiatsionnykh povrezhdennykh volosyanykh follikulov. Avtorskoe svidetel'stvo № 1197191 A1 SSSR, MPK A61N 5/00. RU № 3576756. 30.03.1991. In Russian

8. Danilov RK. Rukovodstvo po gistologii v 2 t. 2-e izd., ispr. i dop. T. 2.- Sankt-Peterburg: SpetsLit, 2011.- 831s. In Russian

9. Myadlets OD, Adaskevich VP. Morfofunktsional'naya dermatologiya. M.: Medlit. 2006.- 752s. In Russian

10. Mil'to IV. Funktsional'naya morfologiya cheloveka. Uchebnik v 3 tomakh. T. 1: Vistserologiya. M.: Logosfera, 2022.- 664s. In Russian

11. Zakharova MK, Okolitenko MS, Gorbulich AV. Morfometricheskaya kharakteristika stepeni povrezhdeniya volosyanykh follikulov pri odnokratnom rentgenovskom obluchenii/ V kn.: Mater. mezhvuz. nauch.-prakt. konf. molod. uch., posvyashch. 95-letiyu so dnya rozhd. prof. A.A. Klishova «Gistogenez, reaktivnost', regeneratsiya tkaney»: elektr. nauchn. izdanie. Sankt-Peterburg: VMA im. S.M. Kirova. 2025.- In Russian. URL: https://elibrary.ru/item.asp?id=80303796&pff=1

12. Balter S, Hopewell JW, Miller DL et al. Fluoroscopically guided interventional procedures: a review of radiation effects on patients' skin and hair. Radiology. 2010 Feb; 254(2):326-341. https://doi.org/10.1148/radiol.2542082312

13. Kotenko KV, Moroz BB, Nasonova TA et al. Experimental model of severe local radiation injuries of the skin after X-rays. Patol Fiziol Eksp Ter. 2013;(4):121-123. In Russian

14. Kharchenko MA. Korrelyatsionny analiz: Uchebnoe posobie dlya vuzov. Voronezh: Izd-vo VGU. 2008.- S. 31.- In Russian

15. Gayduk VA. Sravnitel'naya morfometricheskaya kharakteristika reaktivnykh izmeneniy krovenosnykh sosudov kozhi pri razlichnykh povrezhdeniyakh/V kn.: Innovatsionnye tekhnologii izucheniya gistogeneza, reaktivnosti i regeneratsii tkaney (Trudy Voenno-meditsinskoy akademii). 2024;263:144-147. In Russian

16. Iismaa SE, Kaidonis H, Nicks AM et al. Comparative regenerative mechanisms across different mammalian tissues. NPJ Regen Med. 2018;3(6):1-20. DOI: 10.1038/s41536-018-0044-5

17. Goryachkina VL i dr. Fiziologiya volosyanykh follikulov. Rossiysky zhurnal kozhnykh i venericheskikh bolezney. 2015;3:53-56. In Russian. https://doi.org/10.17816/dv36995

18. Sugaya K, Ishihara Y, Inoue S et al. The effects of gamma rays on the regeneration of hair follicles are carried over to later hair cycles. Int J Radiat Biol. 2015;91(12):957-963. https://doi.org/10.3109/09553002.2015.1101647

19. Shapovalova EYu, Marukyan AKh, Vadyukhin MA i dr. Immunogistokhimicheskaya otsenka proliferatsii i apoptoza keratinotsitov posle odnokratnogo fraktsionnogo ioniziruyushchego oblucheniya. Morfologicheskie vedomosti. 2023;31(3):23-29. https://doi.org/10.20340/mv-mn.2023.31(3).775. In Russian. https://doi.org/10.20340/mv-mn.2023.31(3).775

20. Shlyapkina VI, Kulikov OA, Balashov VP i dr. Morfologicheskie izmeneniya kozhi vyzvannye emul’sionnym fotosensibilizatorom na osnove furanokumarinov borshchevika sosnovskogo. Morfologicheskie vedomosti. 2023;31(2):40-48. In Russian. https://doi.org/10.20340/mv-mn.2023.31(2).757.

21. Petrov VD, Mirgorodskaya EE. Fiziologicheskaya i reparativnaya regeneratsiya epiteliotsitov kornya volosa. Izvestiya Rossiyskoy voenno-meditsinskoy akademii. 2020;39(1-2):131-133. In Russian. https://doi.org/10.17816/rmmar43396