Evaluation of immunohistochemical expression of collagen type I in bone defect treated by local application of collagen and beta-tricalcium phosphate in rats.

Objective: Aims: This study aimed to estimate outcome of combined application of collagen/β-tricalcium phosphate (Coll /β- TCP) on bone defect healing by immuno-histochemical localization of collagen type I.

Patients And Methods: Materials and Methods: A total of 20 adult male rats (albino rats) were used in this study. Four intra bony defects were created in both femurs of each rat, three defects were treated with Coll, β- TCP and combination of Coll /β- TCP while forth defect left to heal spontaneously as control. Scarif i cation of animals was done after 2- and 4-weeks healing periods (10 rats for each). Immunohistochemical localization of collagen type I (COL1) monoclonal antibody was done for all bone specimens.

Results: Results: Immunohistochemical results showed positive expression of (COL1) by bone cells osteoblast (OB), osteocyte (OC), osteoclast (OCL) and bone marrow stromal cells (BMSCs) at 2- and 4-week duration for all examined groups with variable rates of intensity. Mean values of immunoreactive score (IRS) decreased with time for bone cells and for BMSCs except for OC where values increased with time as the highest values were recorded in combination group at 4 weeks.

Conclusion: Conclusions: Combined application of (Coll /β- TCP) was ef f ective in accelerating bone healing process through elevating the IRS of (COL1) noticed by osteo-blast, osteocyte and bone marrow stromal cells.