Objective To investigate the toxic effects of combined yttrium and lead exposure on liver and kidney functions in male Sprague-Dawley (SD) rats. Methods Adult male specific pathogen-free SD rats were randomly divided into four groups. Rats in the low-, medium-, and high-dose groups were co-administered with yttrium acetate (10.0, 50.0, and 100.0 mg/kg body weight, respectively) and lead acetate (4.0, 20.0, and 40.0 mg/kg body weight, respectively) by intragastric gavage, once per day for 28 consecutive days. Rats in the control group received an equal volume of deionized water. Yttrium and lead levels in whole blood, liver, and kidney tissues of the rats were measured using inductively coupled plasma mass spectrometry. Serum index of liver and kidney function were measured by a double reagent method, and histopathological changes in the liver and kidney were observed. Results The body weights of rats in all the three exposure groups were lower than those in the control group from day 14 of exposure until the end of exposure (all P<0.05). Body weight gain of rats was observed only in the low-dose group at day 28, whereas no body weight gain was observed throughout the exposure period in the medium- and high-dose groups. Histopathological examination showed dose-dependent liver and kidney injuries in rats of the three exposure groups compared with the control group. Specifically, the liver exhibited widening of intercellular spaces and increased inflammatory cell infiltration, while the kidney showed increased tissue hemorrhage and increased damage to glomeruli and renal tubules. Lead levels in whole blood, liver, and kidney tissues of the rats were higher than yttrium levels in all the three exposure groups (all P<0.05). Blood yttrium levels in rats of the high-dose group were higher than those in the other three groups (all P<0.05), and yttrium levels in the liver and kidney tissues of the three exposure groups were higher than those in the control group (all P<0.05). Lead levels in whole blood, liver, and kidney tissues of the rats increased with increasing exposure dose (all P<0.05). At the end of exposure, the kidney organ coefficient of rats in the high-dose group was higher than those in the other three groups (all P<0.05). The serum alanine aminotransferase (ALT)/aspartate aminotransferase (AST) ratio of rats in the high‑dose group was lower than that in the control group (P<0.05). The serum urea and uric acid levels in the medium‑ and high‑dose groups were lower than those in the control group (both P<0.05). The serum cystatin C level in the high‑dose group was higher than that in the control group (P<0.05). Blood yttrium and blood lead levels were each negatively correlated with serum ALT/AST ratio, serum urea nitrogen, and uric acid levels (both P<0.05). Both yttrium and lead levels in liver tissue were each negatively correlated with serum ALT/AST ratio (all P<0.05). Both yttrium and lead levels in kidney tissue were each negatively correlated with both serum urea nitrogen and uric acid levels (all P<0.05), and each positively correlated with serum cystatin C levels (both P<0.05). Conclusion Co-exposure to yttrium and lead induces dose‑dependent hepatotoxicity and nephrotoxicity in male SD rats. Lead exhibits a more pronounced accumulation effect and contributes more substantially to the observed toxicity.

Objective To analyze the status of teaching occupational health and occupational medicine course under the background of new medical science, and to construct a semantic knowledge graph to realize the digital teaching reform of the course. Methods i) The literature on teaching research of occupational health and occupational medicine courses published between January 1, 2005 to December 31, 2025 was retrieved through the China National Knowledge Infrastructure. CiteSpace 6.4.R2 and VOSviewer 1.6.20 were used for bibliometric visualization. ii) A knowledge graph system based on Web front-end was constructed using the textbook of Occupational Health and Occupational Medicine (9th ed.), published by People's Medicine Publishing House, as the core data source. Results i) A total of 240 publications related to the teaching in occupational health and occupational medicine courses were included. The overall number of publications showed an upward trend. The research focused on curriculum teaching reform, curriculum-based political education, and digital technology-empowered teaching, forming an interdisciplinary and multi-dimensional research system. The evolution of keywords included three stages: the foundation period (2005-2015), the growth period (2016-2020), and the innovation period (2021-2025). ii) The constructed semantic knowledge graph realizes structural visualization and a dual-mode intelligent question answering agent. A total of four independent navigation modules, including chapter overview, core concept exploration, learning progress details, and relationship network visualization, were used to achieve multidimensional learning pathways. The system requires no installation and supports cross-platform operation, meeting the needs of both teachers and students. It effectively helps students establish systematic knowledge frameworks and enhances interdisciplinary integration ability and learning initiative. Conclusion In the context of new medical science, research on teaching in occupational health and occupational medicine has evolved from a niche field into a research hotspot and entered a stage of high-quality development. The constructed semantic knowledge graph for the Occupational Health and Occupational Medicine course facilitates digital teaching reform in this field and lays a solid foundation for cultivating high-level interdisciplinary occupational health professionals.