The effect of distraction rate on bone histological and histomorphometrical properties in an ovine mandible model

Vol. 52 No. 3 Suppl., 2011
This supplement was not sponsored by Outside Organizations.

ROMANIAN JOURNAL of MORPHOLOGY and EMBRYOLOGY

C. Dinu, W. Kretschmer, Mihaela Baciut, H. Rotaru, Sorana Daniela Bolboaca, D. Gheban, A. Muste, C. Catoi, C. Pestean, G. Baciut

Lengthening the mandible by distraction osteogenesis (DO) is nowadays a well-recognized technique in maxillofacial surgery. This study compared two different distraction rates and evaluated histological and histomorphometrical properties of the distracted bone in an experimental ovine mandible model with the goal of elaborating a universally accepted distraction protocol. Study Design: Tissue blocks of regenerated bone were harvested from twelve young adult sheep. DO was performed on the mandibular midline after five days of latency period. The sheep were divided into two groups. The first group underwent activation of 0.8 mm/day during 12 days resulting in 9.6 mm of new bone while the second group followed a geometric rate pattern of 0.2 mm - three days, 0.4 mm - three days, 0.8 mm - three days and 1.6 mm - three days resulting in 9 mm of new bone. The regenerated bone was histologically and histomorphometrically analyzed after 30, 45 and 60 days of consolidation. The relative osteoid volume (OV/TTV) was significantly increased in the geometric rate distraction group (p=0.015) comparing with linear distraction group while the relative bone volume (BV/TTV) was significantly increased in the linear distraction group (p=0.019) compared to the geometric distraction group.

Corresponding author: Cristian Dinu, Teaching Assistant, e-mail: dinu_christian@yahoo.com; Mihaela Baciut, Professor, e-mail: mbaciut@yahoo.com

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ROMANIAN JOURNAL of MORPHOLOGY and EMBRYOLOGY

F. R. Bob, Gh. Gluhovschi, Diana Herman, Gh. Bozdog, Cristina Gluhovschi, Silvia Velciov, Elena Potencz, Ligia Petrica

Introduction: Glomerular cells (mesangial, endothelial, epithelial) are activated during glomerulonephritis, a process indicated by the expression of the immunohistochemical marker alpha-smooth muscle actin (SMA). Many growth factors participate in the above-mentioned processes, among them of great importance is the transforming growth factor beta (TGF-beta). The result of these changes is represented by active lesions (mesangial matrix increase, mesangial cell proliferation) and chronic fibrotic lesions (glomerulosclerosis). Methodology: We studied a group of 41 patients with primary and secondary glomerulonephritis (24 males, 17 females, mean age 45.5+/-12.9 years), which underwent kidney biopsies, processed in light microscopy. We performed immunohistochemistry procedures with monoclonal antibodies (performed with the LSAB2-HRP system: anti-alpha-SMA, and anti-TGF-beta), which were assessed using a semiquantitative score, that was correlated with the histological and biological data. In order to quantify the histological changes and to assess the extent of active-inflammatory and chronic-sclerotic/fibrotic lesions, we adapted a scoring system initially used only for lupus nephritis, and ANCA-associated vasculitis. Results: TGF-beta expression in glomerular endothelial cells correlated with mesangial matrix increase (r=0.28, p<0.05), total activity index (r=0.29, p<0.05) and total chronicity index (r=0.34, p<0.05). Glomerular epithelial cell TGF-beta correlates with mesangial proliferation (r=0.29, p<0.05), mesangial matrix increase (r=0.4, p<0.01) and total activity index (r=0.28, p<0.05). We observed a strong correlation between endothelial immunolabeling of SMA and the mesangial proliferation score (r=-0.96, p<0.005) and also an indirect correlation with the glomerulosclerosis score (r=-0.35, p<0.05) and the total chronicity index (r=-0.39, p<0.05). Concerning biological data there was a correlation between mesangial SMA expression and serum creatinine (r=0.60, p<0.001) and an indirect correlation with GFR (r=-0.37, p<0.05). Conclusions: We conclude that TGF-beta has a key role in determining glomerulosclerosis especially through mesangial matrix increase, but possibly also through mesangial cells proliferation. Another role of this growth factor is related to transdifferentiation, not only epithelial-mesenchymal, but also endothelial-mesenchymal.

Corresponding author: Flaviu Raul Bob, MD, e-mail: flaviu_bob@yahoo.com

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