Abstract:

Objective  To test expression of carbonic anhydrase Ⅱ（CaⅡ） mRNA in osteoclasts which were applied with fluid shear stress. Methods  The bone marrow cells of Sprague-Dawley rats were cultured with the presence of 1,25-（OH） 2D3 and dexamethasone. The osteoclast-like cells were identified by tartrate-resistant acid phosphatase（TRAP） staining and scanning electron microscope（SEM） observation, then purified with trypsin/ethylenediamine tetraacetic acid （EDTA）. Different values and lasting time of steady fluid shear stress were exerted on the osteoclasts with parallel plate flow system. The CaⅡ expression of osteoclasts were detected by real time reverse transcription-polymerase chain reaction（RT-PCR） and nested polymerase chain reaction（PCR）. Results  The levels of CaⅡ mRNA were down-regulated correspondingly with the increase of stress and time（P＜0.05）. Conclusion  It’s indicated that steady fluid shear stress within a certain range may down-regulate the expression of CaⅡ in osteoclasts.

Key words:  osteoclast, fluid shear stress, bone resorption, carbonic anhydrase Ⅱ, polymerase chain reaction