Fibroblast migration and collagen deposition during dermal wound healing: mathematical modelling and clinical implications,

The extent to which collagen alignment occurs during dermal wound healing determines the severity of scar tissue formation. We have modelled this using a multiscale approach, in which extracellular materials, for example collagen and fibrin, are modelled as continua, while fibroblasts are considered as discrete units. Within this model framework, we have explored the effects that different parameters have on the alignment process, and we have used the model to investigate how manipulation of transforming growth factor-β levels can reduce scar tissue formation. We briefly review this body of work, then extend the modelling framework to investigate the role played by leucocyte signalling in wound repair. To this end, fibroblast migration and collagen deposition within both the wound region and healthy peripheral tissue are considered. Trajectories of individual fibroblasts are determined as they migrate towards the wound region under the combined influence of collagen/fibrin alignment and gradients in a paracrine chemoattractant produced by leucocytes. The effects of a number of different physiological and cellular parameters upon the collagen alignment and repair integrity are assessed. These parameters include fibroblast concentration, cellular speed, fibroblast sensitivity to chemoattractant concentration and chemoattractant diffusion coefficient. Our results show that chemoattractant gradients lead to increased collagen alignment at the interface between the wound and the healthy tissue. Results show that there is a trade-off between wound integrity and the degree of scarring. The former is found to be optimized under conditions of a large chemoattractant diffusion coefficient, while the latter can be minimized when repair takes place in the presence of a competitive inhibitor to chemoattractants

Effect of Ficus hispida L. on normal and dexamethasone suppressed wound healing

Ethanolic extract of roots of Ficus hispida was investigated in normal and dexamethasone depressed healing conditions, using incision, excision and dead space wound models in albino rats. The root extract of Ficus hispida has shown the maximum breaking strength compared to control group. The rate of epithelialization and wound contraction in excision model was better as compared to control groups. There was significant increase in granulation tissue weight and hydroxyproline content in dead space model compared to control group. The antihealing effect of dexamethasone was also reverted by the administration of ethanolic extract of Ficus hispida in all the wound models .The results indicated that the root extract of Ficus hispida has a significant wound healing activity and also promotes healing in dexamethasone depressed healing conditions.O extrato etanólico de raízes de Ficus hispida foi ensaiado em ratos albinos normais e em condições de cicatrização deprimida por dexametasona, utilizando modelos de ferida por incisão, excisão e de espaço morto. O extrato da raiz de Ficus hispida mostrou a força máxima de tensão comparativamente ao grupo controle. A velocidade de epitelização e de contração da ferida no modelo de excisão foi melhor do que a dos grupos controles. Houve aumento significativo no peso do tecido de granulação e no conteúdo de hidroxiprolina no modelo de espaço morto comparativamente ao grupo controle. O efeito anticicatrizante da dexametasona foi, também, revertido pela administração do extrato etanólico de Ficus hispida em todos os modelos de feridas. Os resultados indicaram que o extrato de Ficus hispida tem atividade cicatrizante em feridas e, também, promove a cicatrização em condições de depressão de cicatrização pela dexametasona