Study of the liver of laboratory rats under chronic inhalation exposure to lead oxide nanoparticles

Introduction. Long-term inhalation exposure to lead nanoparticles may increase health risks for workers. The liver is one of their target organs due to its detoxifying function.

The aim of the study is to evaluate hepatotoxic effects of lead oxide nanoparticles following chronic inhalation exposure in an “in vivo” experiment on rats.

Materials and Methods. Female rats were subjected to chronic inhalation exposure to lead oxide nanoparticles at a concentration of 0.2 mg/m³ for 4 hours per day, 5 times a week for 4 months. After cessation of exposure, we evaluated serum biochemical parameters, liver histomorphology and cytogram, nuclear-cytoplasmic ratio and mitochondrial profile of hepatocytes, and apoptotic gene expression.

Results. Increased levels of malondialdehyde, catalase, and C-reactive protein were observed based on blood biochemistry. Inflammatory and degenerative changes in liver tissue were registered. The mitochondrial profile of hepatocytes shifted toward a vesicular swollen morphotype. Elevated expression of the apoptotic bax gene and a trend toward an increasing bax/bcl-2 ratio were detected in rat liver tissue.

Limitations. Laboratory animals used in the experiment belonged to the same species and sex.

Conclusion. Inhalation exposure to PbO NPs at the concentration of 0.2 mg/m³ induced complex hepatotoxic effects in female rats, the key mechanisms of which include oxidative stress, inflammation, and apoptosis.

Compliance with ethical standards. The study was approved by the local Ethics Committee of the Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers (protocol No. 4 of June 12, 2022).

Contributions:
Sutunkova M.P., Minigalieva I.A. – study conception and design;
Shabardina L.V., Gertan N.A. – draft manuscript preparation;
Gavrilova K.A., Sakhautdinova R.R. – data collection and processing;
Shelomentsev I.G., Bereza I.A., Shaikhova D.R., Kikot A.M. – data collection and processing, statistical analysis.
All authors are responsible for the integrity of all parts of the manuscript and approval of its final version.

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

Funding. The study had no sponsorship.

Received: February 4, 2026 / Revised: April 24, 2026 / Accepted: June 18, 2026 / Published: July 31, 2026

1. Shah M.A. Lead oxide (PbO) nanoparticles prepared by a new technique for biomedical applications. Int. J. Biomed. Nanosci. Nanotechnol. 2010; 1(1): 3–9. https://doi.org/10.1504/IJBNN.2010.034121

2. Raj K., Das A.P. Lead pollution: Impact on environment and human health and approach for a sustainable solution. Environ. Chem. Ecotoxicol. 2023; 5: 79–85. https://doi.org/10.1016/j.enceco.2023.02.001

3. Sukhanova A., Bozrova S., Sokolov P., Berestovoy M., Karaulov A., Nabiev I. Dependence of nanoparticle toxicity on their physical and chemical properties. Nanoscale Res. Lett. 2018; 13(1): 44. https://doi.org/10.1186/s11671-018-2457-x

4. Amiri A., Mohammadi M., Shabani M. Synthesis and toxicity evaluation of lead oxide (PbO) nanoparticles in rats. Electronic J. Biol. 2016; 12(2): 110–4.

5. Schindler M., Santosh M., Dotto G., Silva L.F.O., Hochella M.F. Jr. A review on Pb-bearing nanoparticles, particulate matter and colloids released from mining and smelting activities. Gondwana Res. 2022; 110: 330–46. https://doi.org/10.1016/j.gr.2021.07.011

6. Smutna T., Dumkova J., Kristekova D., Lastovickova M., Jedlickova A., Vrlíkova L., et al. Macrophage-mediated tissue response evoked by subchronic inhalation of lead oxide nanoparticles is associated with the alteration of phospholipases C and cholesterol transporters. Part. Fibre Toxicol. 2022; 19(1): 52. https://doi.org/10.1186/s12989-022-00494-7

7. Lebedova J., Novakova Z., Vecera Z., Buchtova M., Dumkova J., Docekal B., et al. Impact of acute and subchronic inhalation exposure to PbO nanoparticles on mice. Nanotoxicology. 2018; 12(4): 290–304. https://doi.org/10.1080/17435390.2018.1438679

8. Alya A., Ines D.B., Montassar L., Najoua G., Saloua E.F. Oxidative stress, biochemical alterations, and hyperlipidemia in female rats induced by lead chronic toxicity during puberty and post puberty periods. Iran. J. Basic Med. Sci. 2015; 18(10): 1034–43.

9. Wan H., Wang Y., Zhang H., Zhang K., Chen Y., Chen C., et al. Chronic lead exposure induces fatty liver disease associated with the variations of gut microbiota. Ecotoxicol. Environ. Saf. 2022; 232: 113257. https://doi.org/10.1016/j.ecoenv.2022.113257

10. Yang C., Li Y., Ding R., Xing H., Wang R., Zhang M. Lead exposure as a causative factor for metabolic associated fatty liver disease (MAFLD) and a lead exposure related nomogram for MAFLD prevalence. Front. Public Heal. 2022; 10: 1000403. https://doi.org/10.3389/fpubh.2022.1000403

11. Sakhautdinova R.R., Sutunkova M.P., Minigalieva I.A., Bushueva T.V. A cytological study of imprint smears (touch preparation cytology) to evaluate the toxicity of metal-containing nanoparticles in experimental animals. Gigiena i Sanitaria (Hygiene and Sanitation, Russian journal). 2020; 99(1): 120–4. https://elibrary.ru/xnxbbx (in Russian)

12. Sun M., Williams J., Munoz-Pinedo C., Perkins G., Brown J., Ellisman M., et al. Correlated three-dimensional light and electron microscopy reveals transformation of mitochondria during apoptosis. Nat. Cell Biol. 2007; 9(9): 1057–65. https://doi.org/10.1038/ncb1630

13. Bereza I.A., Shaikhova D.R., Amromina A.M., Ryabova Yu.V., Minigalieva I.A., Sutunkova M.P. Induction of apoptosis at the molecular genetic level exposed to lead oxide nanoparticles in a chronic animal experiment. Gigiena i Sanitaria (Hygiene and Sanitation, Russian journal). 2024; 103(2): 152–7. https://doi.org/10.47470/0016-9900-2024-103-2-152-157 https://elibrary.ru/pgujba (in Russian)

14. Dumkova J., Smutna T., Vrlíkova L., Docekal B., Kristekova D., Vecera Z., et al. A clearance period after soluble lead nanoparticle inhalation did not ameliorate the negative effects on target tissues due to decreased immune response. Int. J. Mol. Sci. 2020; 21(22): 8738. https://doi.org/10.3390/ijms21228738

15. Bakhtiari M., Hassan N.U., Parveen R., Shahnaz G. Nanoparticles induced oxidative stress: a review based approach. Glob. Drug Des. Dev. Rev. 2021; 6(4): 57–66. https://doi.org/10.31703/gdddr.2021(VI-IV).05

16. Sheinenzon A., Shehadeh M., Michelis R., Shaoul E., Ronen O. Serum albumin levels and inflammation. Int. J. Biol. Macromol. 2021; 184: 857–62. https://doi.org/10.1016/j.ijbiomac.2021.06.140

17. Li Y., Cai W., Ai Z., Xue C., Cao R., Dong N. Protective effects of sinomenine hydrochloride on lead-induced oxidative stress, inflammation, and apoptosis in mouse liver. Environ. Sci. Pollut. Res. 2023; 30(3): 7510–21. https://doi.org/10.1007/s11356-022-22386-1

18. Mansour L.A.H., Elshopakey G.E., Abdelhamid F.M., Albukhari T.A., Almehmadi S.J., Refaat B., et al. Hepatoprotective and neuroprotective effects of naringenin against lead-induced oxidative stress, inflammation, and apoptosis in rats. Biomedicines. 2023; 11(4): 1080. https://doi.org/10.3390/biomedicines11041080

19. Aleksiichuk V., Omelchuk S., Sokurenko L., Kaminsky R., Kovalchuk O., Chaikovsky Y. The influence of lead nanoparticles on the morpho-functional changes of rat liver during the postexposure period. Microsc. Res. Tech. 2018; 81(7): 781–8. https://doi.org/10.1002/jemt.23036

20. Alobaidi F.J., Thaker A.A., Ramizy A. The toxic effect of Pb nanoparticles prepared by laser ablation on some biochemical aspects in rats. Iraqi. J. Phys. 2021; 19(48): 107–14. https://doi.org/10.30723/ijp.v19i48.637

21. Dumkova J., Smutna T., Vrlíkova L., Le Coustumer P., Vecera Z., Docekal B., et al. Sub-chronic inhalation of lead oxide nanoparticles revealed their broad distribution and tissue-specific subcellular localization in target organs. Part. Fibre Toxicol. 2017; 14(1): 55. https://doi.org/10.1186/s12989-017-0236-y

22. Allison D.B., Borzik D., Li Q.K. Liver cytology. In: Jing X., Siddiqui M., Li Q., eds. Atlas of Non-Gynecologic Cytology. Atlas of Anatomic Pathology. Cham: Springer; 2018: 173–98. https://doi.org/10.1007/978-3-319-89674-8_7

23. Fadda L.M., Attia H.A., Al-Rasheed N.M., Ali H.M., Al-Rasheed N.M. Roles of some antioxidants in modulation of cardiac myopathy induced by sodium nitrite via down-regulation of mRNA expression of NF-κB, Bax, and Flt-1 and suppressing DNA damage. Saudi Pharm. J. 2018; 26(2): 217–23. https://doi.org/10.1016/j.jsps.2017.12.008

24. Liu H., Chen C., Wang Q., Zhou C., Wang M., Li F., et al. The oxidative damage induced by lead sulfide nanoparticles in rat kidney. Mol. Cell. Toxicol. 2023; 19(4): 691–702. https://doi.org/10.1007/s13273-022-00296-0

25. Alarifi S., Ali H., Alkahtani S., Alessia M.S. Regulation of apoptosis through bcl-2/bax proteins expression and DNA damage by nano-sized gadolinium oxide. Int. J. Nanomedicine. 2017; 12: 4541–51. https://doi.org/10.2147/IJN.S139326