TOPOGRAPHY OF FORMING AND RESORBING CELLS ON ENDOSTEAL SURFACES OF THE RABBIT HUMERUS BY DOUBLE-STAINING WITH IN-SITU HYBRIDIZATION AND TARTRATE-RESISTANT ACID-PHOSPHATASE REACTION - A NEW MODEL TO STUDY THE BONE REACTION TO LOADING

Since the first investigations made by Wolff, it has been known that b one adapts to mechanical load. The mechanisms which guide the reaction of osteoblasts and osteoclasts to load are still insufficiently known . In situ hybridization (ISH) allows the detection of intracellular ge ne transcripts. Therefore, the ISH technique was further developed to allow the detection of pro-alpha 1 (I) collagen gene transcripts on un decalcified bone surfaces. Additionally, this new technique was combin ed with the tartrate resistant acid phosphatase technique. The combina tion of the two methods allows the detection of forming and resorbing cells on the same undecalcified bone surface. In addition, a new anima l model was developed to study the reaction of bone to mechanical load . This model mimics the situation of bone implants (e.g. hip prosthese ), which is a static situation which is dynamically loaded by the acti on of the patient.