Immunohistochemical study of the possible role of osteoprotegerin OPG in inhibition of otic capsule remodeling

Outcome objectivesTo recognize the differential expression of OPG in the otic capsule of adult male mice compared to other selected skeletal bones both in the nearby location as the temporal bone and in distant bones as the tibia.MethodsThe present experimental study was conducted in 2011 on 20 normal adult male albino mice with an average weight of 50–60 g. Animal housing at the Physiology department (Alexandria Faculty of Medicine) followed the rules of research ethics for experimental animals approved by the Faculty of Medicine, University of Alexandria, Egypt. The following bone specimens were harvested from normal adult male albino mice by microdissection: (1) temporal bone, (2) otic capsule bone surrounding the cochlea, and (3) tibia and stained immunohistochemically for anti-OPG monoclonal antibody. Positive staining was graded and analyzed using image softwares that measure the staining intensity as units of pixels/microscopic field examined at 400 magnification.ResultsOPG was detected as a brown DAB chromogen staining of tissue components expressing a positive OPG monoclonal antibody immune reactivity.Statistical analysis of the results revealed that high OPG level concentrations were found in the otic capsule followed by the temporal bone and finally the tibia.ConclusionThe findings highlight the role of OPG in inhibition of otic capsule remodeling.