Changium smyrnioides, an endangered herb known for its medicinal roots, contains essential amino acids that are vital for human health but cannot be synthesized by the body. However, wild populations of this species have been steadily declining due to the combined impacts of climate change and anthropogenic activities. In this study, we employed an optimized MaxEnt model to predict the potential distribution of C. smyrnioides under different climate scenarios and to evaluate its responses to climate change. Our findings demonstrated that the MaxEnt model achieved optimal performance with a regularization multiplier of 0.5 and a feature combination of linear and quadratic terms. Among the environmental variables, three emerged as the most critical factors shaping the species’ potential distribution: elevation, precipitation of the driest month (bio14), and isothermality (bio2/bio7 × 100, bio3). Currently, the primary suitable habitats for C. smyrnioides are concentrated in Jiangsu Province, with an estimated 21,135 km² classified as highly suitable. The analysis further indicated that, in response to rising temperatures, C. smyrnioides is likely to shift its distribution northeastward across China. Notably, the results suggested that the total area of suitable habitats would increase over time under projected climate scenarios. Based on the predicted centroid migration of suitable habitats, Anhui Province was identified as a critical future conservation zone for C. smyrnioides. This region could serve as a vital refuge, ensuring the long-term survival of the species under changing climatic conditions. Overall, this study provides key insights into the ecological responses of C. smyrnioides to climate change, offering evidence-based guidance for the development of effective conservation strategies aimed at safeguarding this endangered herb.

The reconstruction of extreme long bone defects after malignant tumor resection remains challenging. Short-stem intramedullary implants offer a solution but are often limited by mechanical instability from suboptimal extramedullary fixation. This study assessed how extramedullary low elastic modulus versus high elastic modulus fixation affects osseointegration of these implants by using animal experiments, providing evidence to refine reconstruction techniques. Twenty four rabbits were randomized into LF (low elastic modulus fixation) and HF (high elastic modulus fixation) groups. All received 3D-printed custom short-stem intramedullary implants, differing only in the elastic modulus of the extramedullary fixation component. Weekly x-rays monitored implant stability and complications. Animals were euthanized at 6 and 12 weeks for CT and histological analysis to quantitatively assess callus formation and bone ingrowth into implant threads. X-rays confirmed stable fixation in all animals throughout the observation period. Subsequent CT quantification at 12 weeks demonstrated that the LF group exhibited a significantly greater percentage of callus length relative to total prosthesis length (LF: 55.7 ± 11.4% vs HF: 32.9 ± 8.8%, p < 0.05) and percentage of prosthesis surface wrapped by external callus (LF: 60.8 ± 5.4% vs HF: 31.0 ± 4.7%, p < 0.001). Histological analysis at 12 weeks further confirmed superior osseointegration in the LF group, as evidenced by significantly higher percentage of new bone area in callus relative to predefined thread gap area (LF: 51.8 ± 9.6% vs HF: 7.3 ± 4.1%; p < 0.001), greater percentage of callus-thread edge contact length relative to total thread edge length (LF: 54.1 ± 17.1% vs HF: 7.4 ± 5.7%; p < 0.001), and increased callus penetration depth (LF: 1.637 ± 0.169 mm vs HF: 0.635 ± 0.447 mm; p < 0.05). The Intra-Extramedullary Combined Reconstruction Technique is a reliable method for major bone defect reconstruction. This study provides direct comparative evidence that low elastic modulus extramedullary fixation, unlike its high modulus counterpart, significantly enhances peri-implant callus formation and osseointegration. This represents a novel and important refinement in reconstruction strategy, contributing directly to the potential for long-term implant stability.