Collagen type I prevents glyoxal-induced apoptosis in osteoblastic cells cultured on titanium alloy.
Advanced glycation end products (AGEs) irreversibly cross-link proteins with sugars and accumulate at a higher age and in diabetes, processes which can interfere with the integration of implants into the tissue. Glyoxal is a highly reactive glycating agent involved in the formation of AGEs and is known to induce apoptosis, as revealed by the upregulation of caspase-3 and fractin (caspase-3 being a key enzyme activated during the late stage of apoptosis and fractin being a caspase-cleaved actin fragment). In this study, we investigated the influence of collagen type I coating on the cytotoxic effect of glyoxal on rat calvarial osteoblastic cells and on human osteosarcoma cells (Saos-2) grown on titanium alloy, Ti6Al4V. Activation of caspase-3 and fractin was measured by counting immunohistochemically stained cells and by flow cytometry with propidium iodide (detection of the apoptosis indicating a sub-G1 peak). Our results showed an increased number of apoptotic osteoblasts after incubation with glyoxal on Ti6Al4V discs. However, the number of apoptotic cells on collagen-coated titanium was significantly smaller than on uncoated titanium after the same treatment. The present findings demonstrate that osteoblasts treated with glyoxal undergo apoptosis, whereas collagen type I coating of titanium alloys (used for implants) has an antiapoptotic function.
Tippelt
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Department of Anatomy, Technical University, Dresden, Germany. Sonja.Tippelt@mailbox.tu-dresden.de
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Witt
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Bierbaum
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Funk
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D000497:Alloys / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D018929:Cell Culture Techniques / Q000379:methods; D002460:Cell Line; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism; D024042:Collagen Type I / Q000502:physiology*; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D017127:Glycation End Products, Advanced / Q000378:metabolism; D006037:Glyoxal / Q000494:pharmacology*; D006801:Humans; D007150:Immunohistochemistry; D008856:Microscopy, Fluorescence; D010006:Osteoblasts / Q000378:metabolism / Q000473:pathology*; D012516:Osteosarcoma / Q000378:metabolism; D051381:Rats; D013997:Time Factors; D014025:Titanium / Q000494:pharmacology*; D015854:Up-Regulation
D000497:Alloys; D002843:Chromatin; D024042:Collagen Type I; D003432:Cross-Linking Reagents; D017127:Glycation End Products, Advanced; D006037:Glyoxal; D014025:Titanium; C505407:CASP3 protein, human; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases