A rapid silver nitrate histological staining technique for studying the osteocyte lacunocanalicular system

The Ploton silver method employs a 50% silver nitrate solution (w/v; 2.943 mol/L) for staining and quantitative analysis of the osteocyte lacuno-canalicular system (LCS). We previously demonstrated that lower silver nitrate concentrations (0.5-1 mol/L) stain the LCS more effectively, revealing a greater number of LCS than the Ploton silver method. However, the staining duration of our initial modified method (60 minutes) remained comparable to that of the Ploton silver method (55 minutes), limiting its broader adoption. Here, we developed a rapid silver nitrate staining method by systematically evaluating the effects of temperature on staining efficacy. We found that incubation at 50-70 degrees Celsius for 10 minutes with a 1 mol/L silver nitrate solution produced optimal results. This rapid high-temperature method achieved excellent LCS visualization in bone samples from multiple animal species and in mouse pathological models. Moreover, high-temperature staining mitigated the LCS damage and insufficient staining associated with the 50% silver nitrate solution used in the Ploton silver method. This rapid 10-minute silver staining technique, designated the Wu-Wang silver method, provides a more accurate and efficient approach for LCS staining and quantitative analysis. Its adoption will facilitate systematic characterization of LCS morphological variations across vertebrate species, thereby advancing our understanding of osteocyte morphogenesis and the pathogenic mechanisms underlying bone and joint diseases.