Ki-67 immunohistochemical staining with heat-induced epitope retrieval in rat tibial and femoral growth plates

Abstract

Proliferation is an important assessment in both clinical and research applications. Ki-67 has been shown to be a reliable immunohistochemical marker for actively dividing cells, but challenges exist for performing the staining on delicate or difficult tissues. Bone is one of these difficult tissues because the retrieval protocol required to detect the Ki-67 antigen often results in loss of tissue from the slide. We propose a new method for clear immunohistochemical labeling of rat tibial growth plate with Ki-67. This new method includes using thinner sections, decreasing sectioning artifact and increasing primary antibody incubation time. These changes, paired with optimal baking time of slides before staining, result in quantifiable nuclear labeling within the rat tibial and femoral growth plates.