ABSTRACT
Introduction ....................................................................................................... 186 Structure-Function Relationship of Tissues and Cells ...................................... 186
Articular Cartilage: Chondrocytes ............................................................... 187 Ligament: Fibroblasts................................................................................... 188 Meniscus: Inner and Outer Meniscus Cells ................................................. 188 Synovial Membrane: Type B Synoviocytes/Synovial Mesenchymal Stem Cells (sMSCs) ..................................................................................... 188 Bone: Osteoblasts and Osteoclasts ............................................................... 189
Galvanotaxis...................................................................................................... 189 Chondrocytes .................................................................................................191 Ligament Fibroblasts .................................................................................... 192 Inner and Outer Meniscus Cells ................................................................... 193 Synovial Mesenchymal Stem Cells .............................................................. 194 Osteoblasts and Osteoclasts ......................................................................... 194
Mechanisms Involved in Galvanotaxis ............................................................. 194 Tissue Regeneration and Future Directions ...................................................... 196 References ......................................................................................................... 197
Injuries to soft tissues such as ligaments, tendons, and the knee meniscus can lead to concomitant injury to surrounding joint tissues, eventually resulting in osteoarthritis. Arthritis today is the leading cause of disability among adults in the United States, according to the U.S. Centers for Disease Control and Prevention (CDC Data and Statistics, 2009). Thus, the development of strategies to aid in the repair or regeneration of injured tissues is paramount to minimize and delay joint degeneration. A popular method of tissue regeneration is to use bioreactors that attempt to mimic in vivo conditions for generating new tissues de novo (Abousleiman and Sikavitsas, 2006). In certain instances, however, tissue repair may be a more feasible option, and this is usually performed through invasive surgery or by the body’s own intrinsic defense mechanisms, such as migration of healthy cells into the damaged area. Cell migration may be an important component of soft tissue repair, as previous work has shown that meniscal allografts (Jackson and Simon, 1993) and devitalized meniscal plugs (Kambic et al., 2000) can be repopulated with cells when placed in vivo. One possible stimulus to enhance and direct cell migration is electric šelds, which have been shown to induce galvanotaxis. In vivo, endogenously generated electric šeld gradients are known to guide cell migration during wound healing and embryonic development (Robinson, 1985); thus, they may provide a similar benešt for damaged soft tissue (see Chapters 3-8 and 10).
