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  RESEARCH ACTIVITY > Department of Human Anatomical Sciences and Physiopathology of Locomotor apparatus  
Department of Human Anatomical Sciences and Physiopathology of Locomotor apparatus
Research Group
Maria Macciocca PhD Student

University of Bologna - Division of Human Anatomy
Department of Human Anatomical Sciences and Physiopathology of Locomotor apparatus
Via Irnerio, 48 - 40126 Bologna

Background and specific aims
1) Fibrous connective tissue collagen under normal and paraphysiological conditions
During muscle stretching the muscle-tendon unit is subjected to unidirectional tensional forces. Many studies have investigated muscle tissue subjected to stretching but none have tackled the morphological and functional adaptation of tendinous tissue.
The goals of the in vivo experimental study on animals are:
a) To disclose any structural and biochemical changes to the cellular and extracellular components of tendons periodically subjected to stretching under conditions and techniques similar to those of static stretching;
b) Ascertain whether such changes already appear after a first application of stretching force or after repeated stretching over time (training);
c) Determine whether such changes are reversible by suspending periodic stretching exercises.

2) Collagen microfibrils and fibrils: morphofunctional correlations
The microfibrillar organization of collagen fibrils in different body districts and tissues appears to be closely correlated to the different biomechanical demands of different tissues. Three groups of tissues including two types of collagen fibrils with a different microfibrillar organization have been identified to date:
a) Tendons in which collagen fibrils, termed type T, are arranged in parallel fibre bundles and subjected to mainly unidirectional tensional forces. On average these fibrils are large calibre, plurimodal and include microfibrils oriented at 5° to the fibrillar axis.
b) The skin, blood vessels, nerve and tendon sheaths, mucous membranes in which type C collagen fibrils have a variable trend and are subjected to multidirectional forces. The fibrils are small calibre, unimodal and have a helicoidal arrangement at 17°.
c) Different ligaments comprising both type T and type C fibrils.
The goal of the study is to shed light on the structural organization of connective tissues in different anatomical sites.

3) Metal implant surfaces and biological integration
Primary mechanical stability, the basic requirement for final implant osteointegration is soon followed by the development of a biological fixation of the implant which is achieved by the formation of a blood clot and subsequent tissue scarring and peri-implant bone tissue repair. In order to determine which implant surfaces boost the early stages of implant tissue integration, small titanium plates with different implant surfaces are inserted into the bone marrow of animals to examine the cell types adhering to the surface and follow their evolution in vitro cultures using different factors favouring osteogenetic activity.
The goal of the study is to identify the best implant surfaces and biological factors favouring early osteointegration.

Research projects
- Morphofunctional changes to Achilles’ tendon after static stretching and following physical exercise;
- Effects of motor activity on tendons during aging;
- Structure and structural changes to human tendons and ligaments used for surgical replacement techniques;
- Role of surface morphology and the biological microenvironment in the osteointegration of endosseous implants.
Facilities and equipment
Light Microscopy Laboratory with light microscopes and fluorescence and polarized light microscopes, microtomes, cryostat, saw and grinding system; Electron Microscopy Laboratory housing: ultramicrotomes, freeze-etching, TEM, SEM, high resolution SEM, metallizers and critical point drying apparatus.
Figure 1: Polarized light microscope picture of longitudinally sectioned rat Achilles tendon. Collagen fiber bundles show a crimping pattern characterized by alternating periodic dark and light bands. These structures corresponds to the tendon crimps.

Figure 2: Light microscopy. The gap between an implant surface and the host bone is completely filled with immature early new trabecular bone. These trabeculae lead to a good biological fixation which is already evident two weeks after surgery. Bar:100 mm.

Recent pubblications
Crimp morphology in relaxed and stretched rat Achilles tendon. - Franchi M., Fini M., Quaranta M., De Pasquale V., Raspanti M., Giavaresi G., Ottani V., Ruggeri A. - J. Anat. 210, 1-7. ( 2007 )
Self-aggregation of fibrillar collagens I and II involves lysine side chains. - Tenni R., Sonaggere M., Viola M., Bartolini B., Tira ME., Rossi A., Orsini E., Ruggeri A.,Ottani V. - Micron 37, 640-7. ( 2006 )
Biological fixation of endosseous implants. - Franchi M., Fini M., Martini D., Orsini E., Leonardi L., Ruggeri A., Giavaresi G., Ottani V. - Micron 36, 665-71 ( 2005 )
The 3D structure of crimps in the rat Achilles tendon. - Raspanti M., Manelli A., Franchi M., Ruggeri A. - Matrix Biology 24, 503-507. ( 2005 )
Early detachment of titanium particles from various different surfaces of endosseous dental implants. - Franchi M., Bacchelli B., Martini D., De Pasquale V., Orsini E., Ottani V., Fini M., Giavaresi G., Giardino R., Ruggeri A. - Biomaterials 25, 2239-46. ( 2004 )
Hierarchical structures in fibrillar collagens. - Ottani V., Martini D., Franchi M., Ruggeri A., Raspanti M. - Micron, 33, 587-96. ( 2002 )

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