Studies reviewed consistently demonstrated the ability of laser or monochromatic light to photobiomodulate wound healing processes in experimental wounds in rats and mice, and strongly support the case for further controlled research in humans.

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Findings from studies of cells in culture clearly demonstrate the ability of laser irradiation to modulate (typically stimulate) cellular proliferation. The relevance of some irradiation parameters remains occult and represents an important area for further research.

Findings from the reviewed studies clearly demonstrate the ability of laser irradiation to modulate gene expression and the release of growth factors and cytokines from cells in culture. Further work is indicated at the clinical level to elucidate the putative clinical relevance of these cellular-level effects.

Reconstituted keratin has potential as a raw material for orthopaedic applications. The aim of this study was to investigate the in vivo biocompatibility and osseointegration of keratin materials in an ovine model. Six different modifications of the keratin polymer, based on porous or dense constructs, regenerated by either neutral or acidic treatment, with or without hydroxyapatite, were made as small rods and inserted into drilled round defects in the femur and tibia of sheep. Histology was carried out on samples taken at different time points up to 24 weeks postsurgery. All keratin implants showed similar histological profiles, which included granulation tissue surrounding and infiltrating the implants, followed by new bone formation radiating from the existing bone. By 8 weeks, new bone had grown to within a short distance of the implant surface, and in some places was in direct apposition to the keratin implant. In the 12 to 24-week period, there was peripheral resorption and infiltration of bony trabeculae with regard to the porous constructs only. The tissue reaction appeared to model that of a fairly inert material. Further work on improving the extent of osseointegration and acceleration of the biodegradation rate of reconstituted keratin is underway.