Viability assessment of osteocytes using histological lactate dehydrogenase activity staining on human cancellous bone sections.

The assessment of viable osteocytes within bone tissue is of crucial importance. Osteocytes are the most abundant cells in bone. Due to their interconnectivity in the bone matrix they are hypothesised to play an important role in the maintenance of the extracellular matrix of bone. The death of osteocytes and the resulting disturbance of the osteocyte-canalicular network are responsible for the "loss of function" seen in several bone diseases. The lactate dehydrogenase (LDH) assay is a popular method to detect cell viability in bone sections. The major advantage of the LDH assay is the stability of the LDH enzyme for up to 36 h after cell death, eliminating any false negative viability results due to processing of the tissue. Here, we present a quick, reliable, and easy modification of the LDH assay using non-decalcified, thick, unfixed cancellous bone sections for the quantification of osteocyte viability.