A Novel Optimized Silver Nitrate Staining Method for Visualizing and Quantifying the Osteocyte Lacuno-Canalicular System (LCS)

The osteocyte lacuno-canalicular system (LCS) plays a crucial role in maintaining bone homeostasis and mediating cellular mechanotransduction. Current histological techniques, particularly the Ploton silver nitrate staining method, face challenges such as variations in solution concentrations and types as well as a lack of standardization, which limits their broader application in osteocyte research. In this study, we present a simplified and more effective silver nitrate staining protocol designed to address these issues. Our method utilizes a 1 mol/L silver nitrate solution combined with optimized gelatin-formic acid solutions at varying concentrations (0.05%-0.5% type-B gelatin and 0.05%-5% formic acid, or 1%-2% type-B gelatin and 0.1%-2% formic acid). Staining is performed for 1 h under 254 nm ultraviolet light or 90 min under room light, followed by washing with Milli-Q water to terminate staining. This novel optimized method yields consistent and distinct staining of the osteocyte LCS across multiple species, demonstrating superior efficiency and reliability compared to the Ploton method. It will significantly advance research in osteocyte biology and provide a valuable tool for exploring the adaptive evolution of osteocyte LCS morphology and function across various taxa. Key features • A novel optimized silver nitrate method using a 1 mol/L silver nitrate solution with type-B gelatin-formic acid solution effectively stains the osteocyte LCS. • The novel optimized method is more efficient for staining the osteocyte LCS across different species. • The novel optimized method is simpler to perform and more cost-effective than conventional methods. Graphical overview <b>Overview of the silver nitrate staining method for staining and qualifying osteocyte lacuno-canalicular system (LCS).</b> Created in BioRender. Libo, W. (2024) https://BioRender.com/c10z002.