Introduction. A promising direction of nanotoxicology is the study of the effect of gadolinium nanoparticles on the body, which is possible using high-molecular compounds, for example, Siberian larch arabinogalactan, which has a stabilizing effect on nanoparticles.

Materials and methods. As part of experimental studies, subacute (within 10 days) intragastric effects were carried out on outbred sexually mature male white rats (sixty four individuals) of gadolinium nanocomposite encapsulated in a natural polymer matrix of arabinogalactan at a dose of 500 µg/kg body weight and 5000 µg/kg body weight, respectively. The examination took place in 2 stages: immediately after the end of the seed (early period) and 6 months after the end of the exposure (long-term period). The work used a set of studies aimed at determining gonadotoxicity – histological examination of the tissues of the spermatogenic epithelium, morphometrically determined the general indicator of functional activity of the testes – the index of spermatogenesis.

Results. Based on the conducted experimental studies, there has been established gonadotoxic effect of gadolinium nanoparticles on the reproductive system in male rats, expressed in the destruction of the germinal epithelium of the seminal tubules with a violation of the normal process of spermatogenesis with the administration of both doses of the studied nanocomposite, while in the long term the indicators do not return to normal. Also gadolinium nanoparticles have been established to be able to penetrate the hemato-testicular barrier, accumulating in testicular tissues.

Limitations. The number of animals and the set of techniques is sufficient to study the effects of gadolinium nanoparticles encapsulated in the polysaccharide arabinogalactan on the structural and functional state of testicular tissue.

Conclusion. With subacute exposure to gadolinium nanoparticles encapsulated in an arabinogalactan matrix, there has been established their gonadotoxic effect on the male reproductive system, expressed by structural and functional changes in testicular tissue.

Compliance with ethical standards. The work was carried out in accordance with the protocol of experimental research, the principles set out in the European Convention for the Protection of Vertebrate Animals Used for Experiments or Other Scientific Purposes ETS No. 123, GOST 33215-2014 “Guidelines for the care and care of laboratory animals. Rules of equipment of premises and organization of procedures”, Recommendations for euthanasia of experimental animals: Part 1, Part 2. Permission was obtained from the Local Ethics Committee to conduct research (Protocol No. 8 dated 12/15/2023).

Contribution: Novikov M.A. – concept and design of research, data processing, editing, writing text; Titov E.A. – concept and design of research, editing; Pankova A.A. – collection of material and data processing; Lisetskaya L.G. – data processing; Sosedova L.M. – concept and design of research, editing, writing text. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.

Acknowledgment. The team of authors would like to thank Yu.Y. Titova, Head of the Laboratory of functional nanomaterials of the Federal Research Center “A.E. Favorsky Irkutsk Institute of Chemistry’, the Siberian Branch of the Russian Academy of Sciences for her help in conducting research to determine the dimensional characteristics of gadolinium nanoparticles.

Conflict of interest. The authors declare no conflict of interest.

Funding. The study was carried out within the framework of the state assignment of the East Siberian Institute of Medical and Environmental Research.

Received: September 12, 2025 / Accepted: November 3, 2025 / Published: December 19, 2025