Induction of chronic marginal periodontitis in an experimental sheep model: clinical, radiological and histological evaluation

AbstractDespite the high potential of healthy bone to regenerate, the reconstruction of large bone defects remains a challenge. Due to the lack of mechanical stability of existing bone substitutes, recently developed degradable metallic alloys are an interesting alternative providing higher load-bearing capabilities. Degradable iron-based alloys therefore might be an attractive innovation. To test the suitability of a newly-designed iron-based alloy for such applications, an animal experiment was performed. Porous iron-based degradable implants with two different densities and a control group were tested. The implants were positioned in the proximal tibia of Merino sheep. Over a period of 6 and 12 months, blood and histological parameters were monitored for signs of inflammation and degradation. In the histological evaluation of the implants` environment we found degraded alloy particles, but no inflammatory reaction. Iron particles were also found within the popliteal lymph nodes on both sides. The serum blood levels of phosphorus, iron and ferritin in the long term groups were elevated. Other parameters did not show any changes. Iron-based degradable porous bone replacement implants showed a good biocompatibility in this experiment. For a clinical application, however, the rate of degradation would have to be significantly increased. Biocompatibility would then have to be re-evaluated.

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Combined Nucleus Pulposus Augmentation and Annulus Fibrosus Repair Prevents Intervertebral Disc Degeneration After Discectomy

Neurosurgery ◽

10.1093/neuros/nyz310_816 ◽

2019 ◽

Vol 66 (Supplement_1) ◽

Author(s):

Sertac Kirnaz ◽

Stephen Sloan ◽

Christoph Wipplinger ◽

Franziska Anna Schmidt ◽

Roger Hartl ◽

...

Keyword(s):

Nucleus Pulposus ◽

Disc Degeneration ◽

Annulus Fibrosus ◽

Combined Treatment ◽

Disc Height ◽

Histological Evaluation ◽

Sheep Model ◽

Mri Scans ◽

The Individual

Abstract INTRODUCTION The objective of the current study is to assess the efficacy of combined annulus fibrosus (AF) using a high-density collagen (HDC) gel and nucleus pulposus (NP) repair using a hyaluronic acid (HA) gel in an in Vivo sheep model. METHODS We performed an anterolateral, retroperitoneal prepsoas approach to access the IVDs L1-6 in a total of 8 skeletally mature Finn sheep. IVDs were randomized into 5 groups: (1) intact, (2) injured via 3 × 10 mm box annulotomy and removal of 200 mg of NP, (3) injury and HDC gel patch for AF repair, (4) injury and injection of a HA gel into the NP, and (5) injury and HDC AF repair and NP HA replacement. At 6 wk postoperatively, sheep were sacrificed and underwent postmortem 3T-MRI scans as well as gross anatomical and histological evaluation. Disc height index (DHI) analysis and Pfirrmann grading (PG) were performed on each segment using MR images. RESULTS Intact control discs were not degenerated and had an average PG of 1 while injured, and untreated discs had a significant degeneration with an average PG of 3. Discs receiving the combined injection and collagen AF patch individually showed fewer signs of degeneration than injured alone, and the combined treatment resulted in the least amount of degeneration with PG not significantly different from the intact controls. DHI confirmed the trends seen in the PG, where injured discs lost 20% of the intact disc height, the individual NP and AF repairs restored 5% to 10% of intact disc height, and the combined repairs preserved 90% of the intact disc height. CONCLUSION PG and DHI results demonstrate that individual NP and AF repairs are able to prevent disc degeneration better than no treatment at all; however, the greatest preservation of disc health was seen with combined AF and NP repairs.

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Hybrid Chitosan Membranes Tested in Sheep for Guided Tissue Regeneration

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.361-363.1265 ◽

2007 ◽

Vol 361-363 ◽

pp. 1265-1268 ◽

Cited By ~ 3

Author(s):

P.P. Cortez ◽

Yuki Shirosaki ◽

C.M. Botelho ◽

M.J. Simões ◽

F. Gartner ◽

...

Keyword(s):

Inflammatory Response ◽

Tissue Regeneration ◽

Chitosan Solution ◽

Clinical Applications ◽

Histological Evaluation ◽

Sheep Model ◽

The Third ◽

Chitosan Membranes

Previous in vitro studies confirmed an improved cytocompatibility of chitosan-silicate hybrid membranes over chitosan membranes. The main goal of this study was to assess the in vivo histocompatibility of both membranes through subcutaneous implantations at different time periods, 1 week, 1, 2 and 3 months, using a sheep model. Chitosan membranes elicited an exuberant inflammatory response and were consequently rejected. The hybrid chitosan membranes were not rejected and the degree of inflammatory response decreased gradually until the third month of implantation. Histological evaluation also showed that these membranes can be resorbed in vivo. This study demonstrates that the incorporation of silicate into the chitosan solution improves its histocompatibility, indicating that the hybrid chitosan-silicate membranes are suitable candidates to be used in clinical applications.

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Evaluation of hydroxyapatite ceramic vertebral spacers with different porosities and their binding capability to the vertebral body: an experimental study in sheep

Journal of Neurosurgery Spine ◽

10.3171/spi.2007.6.5.431 ◽

2007 ◽

Vol 6 (5) ◽

pp. 431-437 ◽

Cited By ~ 8

Author(s):

Manabu Ito ◽

Yoshihisa Kotani ◽

Yoshihiro Hojo ◽

Kuniyoshi Abumi ◽

Tsuyoshi Kadosawa ◽

...

Keyword(s):

Bone Ingrowth ◽

Histological Study ◽

Biomechanical Testing ◽

Histological Evaluation ◽

Micro Computed Tomography ◽

Hydroxyapatite Ceramic ◽

Sheep Model ◽

Spinal Reconstruction ◽

Computed Tomography Scans ◽

The Ideal

Object The aim of this study was to evaluate the degree of bone ingrowth and bonding stiffness at the surface of hydroxyapatite ceramic (HAC) spacers with different porosities in an animal model and to discuss the ideal porous characteristics of these spacers for anterior spinal reconstruction. Methods Twenty-one adult sheep (age 1–2 years, mean weight 70 kg) were used in this experiment. Surgery consisted of anterior lumbar interbody fusion at L2–3 and L4–5, insertion of an HAC spacer (10 × 13 × 24 mm) with three different porosities (0, 3, and 15%), and single-rod anterior instrumentation. At 4 and 6 months postoperatively, the lumbar spines were harvested. Bonding conditions at the bone–HAC spacer interface were evaluated using neuroimages and biomechanically. A histological evaluation was also conducted to examine the state of bone ingrowth at the surface of the HAC spacer. Biomechanical testing showed that the bonding strength of HAC at 6 months postoperatively was 0.047 MPa in 0% porosity spacers, 0.39 MPa in 3%, and 0.49 MPa in 15% porosity spacers. The histological study showed that there was a soft-tissue layer at the surface of the HAC spacer with 0% porosity. Direct bonding was observed between bone and spacers with 3 or 15% porosity. Micro–computed tomography scans showed direct bonding between the bone and HAC with 3 or 15% porosity. No direct bonding was observed in HAC with 0% porosity. Conclusions Dense (0%) HAC anterior vertebral spacers did not achieve direct bonding to the bone in the sheep model. The HAC vertebral spacers with 3 or 15% porosity showed proof of direct bonding to the bone at 6 months postoperatively. The higher porosity HAC spacer showed better bonding stiffness to the bone.

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Arthroscopic Tenotomy of the Long Head of the Biceps Tendon and Section of the Anterior Joint Capsule Produce Moderate Osteoarthritic Changes in an Experimental Sheep Model

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18147471 ◽

2021 ◽

Vol 18 (14) ◽

pp. 7471

Author(s):

Umile Giuseppe Longo ◽

Francisco Forriol ◽

Vincenzo Candela ◽

Salvatore Maria Tecce ◽

Sergio De Salvatore ◽

...

Keyword(s):

Shoulder Joint ◽

Glenohumeral Joint ◽

Biceps Tendon ◽

Joint Capsule ◽

Quantitative Mri ◽

Degenerative Changes ◽

Histological Evaluation ◽

Sheep Model ◽

Long Head ◽

Development And Evolution

Osteoarthritis (OA) of the glenohumeral (GH) joint is a common cause of shoulder pain, resulting in considerable invalidity. Unfortunately, the study of its pathogenesis is challenging. Models of OA are necessary to identify specific targets for therapy and to be able to interfere with the development and evolution of OA. This study aims to assess the effect of an arthroscopic tenotomy of the long head of the biceps tendon (LHBT) and section of the anterior glenohumeral joint capsule on the ovine glenohumeral joint. In addition, the authors aim to validate and evaluate the reliability of a modified semi-quantitative MRI score to assess joint degeneration in a sheep’s shoulder. Eight skeletally mature sheep received an arthroscopic tenotomy of the LHBT and section of the anterior joint capsule and were euthanized four months after surgery. All animals tolerated the surgery well, and no complication was recorded for six weeks. Moderate degenerative changes to the ovine shoulder joint were found on MRI and histological evaluation. The arthroscopic tenotomy of the LHBT and the anterior glenohumeral joint capsule section caused moderate degenerative changes to the ovine shoulder joint.

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Histological Evaluation of a New Concept Eliminating the Need for Suture or Glue During Fallopian Tube Anastomosis in the Sheep Model

Geburtshilfe und Frauenheilkunde ◽

10.1055/s-2005-865811 ◽

2005 ◽

Vol 65 (7) ◽

pp. 682-686

Author(s):

H. Kaya ◽

O. Ozkaya ◽

M. Sezik ◽

A. R. Aydin ◽

R. Dittrich

Keyword(s):

Fallopian Tube ◽

Histological Evaluation ◽

Sheep Model

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Local and Systemic Inflammation After Implantation of a Novel Iron Based Porous Degradable Bone Replacement Material in Sheep Model

10.21203/rs.3.rs-138400/v1 ◽

2021 ◽

Author(s):

Bernd Wegener ◽

Maik Behnke ◽

Stefan Milz ◽

Volkmar Jansson ◽

Christian Redlich ◽

...

Keyword(s):

Mechanical Stability ◽

Bone Substitutes ◽

Histological Evaluation ◽

Control Group ◽

Blood Levels ◽

Porous Iron ◽

Sheep Model ◽

Bone Replacement Material ◽

Bone Replacement ◽

Iron Based

Abstract Despite a high regenerative potential of healthy bone, replacement of large bone defects is an currently ongoing medical challenge. Due to a lack of mechanical stability of existing bone substitutes, recently developed degradable metallic alloys are an interesting alternative providing higher load bearing properties. Degradable iron-based alloys are an attractive innovation. Therefore, a degradable iron-based bone replacement material has been developed.To test the suitability of a newly designed iron-based alloy, an animal experiment was performed. Porous iron-based degradable implants with two different densities and a control group were tested. The implants were positioned in the proximal tibia. Over a period of 6 and 12 months, blood and histological parameters were monitored for signs of inflammation and degradation. Even if degradation at the desired rate was not achieved, in the histological evaluation of the implants` environment we found degraded particles, but no inflammatory reaction. Iron particles were also found within the popliteal lymph nodes on both sides. The serum blood levels of phosphorus, iron and ferritin in the long term groups were elevated. Other parameters did not show any changes.Iron-based degradable porous bone replacement implants showed a good biocompatibility in this experiment. For a clinical application, however, the rate of degradation would have to be significantly increased. Biocompatibility would then have to be re-evaluated.

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