Editorial: New insight into immune cells in the development of nontraumatic osteonecrosis of the femoral head Provisionally Accepted

Yu Zhou¹ Jinhui Ma¹ Qingyu Zhang^2* Bailiang Wang^1*

• ¹China-Japan Friendship Hospital, China
• ²Shandong Provincial Hospital, China

. Osteonecrosis of the femoral head (ONFH) is a challenging condition characterized by compromised subchondral microcirculation and osteocyte apoptosis (Mont et al., 2020).Currently, the pathogenesis of ONFH remains incompletely elucidated, but recent researches highlight the crucial role of immune factors in the onset and progression of this condition. Under normal circumstances, a balance is maintained between osteoblasts and osteoclasts, with immune cells playing a significant role in preserving this equilibrium. When ONFH occurs, locally damaged cells release a substantial amount of chemotactic and cytokine factors, disrupting immune balance. The growth factor-cytokine imbalance needs to be corrected. If not corrected, osteoclasts will become more active than osteoblasts over time, which would make bone repair difficult and eventually lead to irreversible collapse of the femoral head. If this imbalance is challenging to correct, osteoclasts gradually become more active than osteoblasts, making bone repair difficult and eventually leading to irreversible collapse of the femoral head. This research project comprises four articles that delve deeper and strengthen our understanding of non-traumatic femoral head necrosis (Wang et al., 2022;Ma et al., 2019).With the evolution of microfluidic systems, organ-on-chip has become a trending topic. (Fan et al., 2023).Femoral head collapse is a crucial signal of the deterioration of ONFH, associated with alterations in the trabecular structure within the femoral head. He et al. employed techniques such as immunohistochemistry, micro-CT, nanoindentation, acid-etched scanning electron microscopy, and others to assess and compare the ultrastructural changes in bone cell morphology and nanomechanical features in different regions of necrotic femoral heads (He et al., 2023). Their research findings are of paramount importance for our understanding of the microstructural and macro-mechanical alterations in the progression of femoral head necrosis.Currently, magnetic resonance imaging remains the gold standard for early diagnosis of femoral head necrosis, but it is expensive and time-consuming. Xu et al. utilized Phase-contrast imaging (PCI) with synchrotron hard X-ray to observe the impact of icariin, the primary bioactive compound found in the traditional Chinese herb Epimedium brevicornum known for "strengthening bone and tonifying kidney", on the early glucocorticoid-induced osteonecrosis of the femoral head rabbit model. The reliability of this technique was confirmed through bone tissue morphological observations and HE staining. PCI with synchrotron hard X-ray demonstrated the capability to visualize the microstructure of the femoral head, which is comparable to Micro-CT and HE staining (Yang et al., 2023). It could potentially serve as a noninvasive alternative for histological examination in the early diagnosis of ONFH.