RESUMO
The effect of a lyophilized cell lysate prepared from cultured human keratinocytes on the healing of full-thickness wounds was evaluated in an impaired healing model. Full-thickness wounds (8 mm in diameter) were made on the dorsal areas of female genetically diabetic mice C57 BL/KsJ (db/db) and their normal (db/+) littermates. Wounds were covered with an occlusive polyurethane film dressing and were treated for 5 days either with the lyophilized cell lysate from cultured human keratinocytes prepared in phosphate-buffered saline solution or with phosphate-buffered saline solution. In normal (db/+) mice, all wounds were closed 16 days after wounding, and more than 90% of the wound closure was due to wound contraction. Wound contraction accounted for a similar extent of wound closure in both lyophilized cell lysate-treated and phosphate-buffered saline solution-treated wounds. In contrast, in the diabetic (db/db) mice, after histologic examination of the wounds 32 days after wounding, four of ten lyophilized cell lysate-treated wounds and four of seven phosphate-buffered saline-treated wounds were found to be closed. Moreover, applications of lyophilized cell lysate from cultured human keratinocytes to full-thickness wounds in diabetic db/db mice significantly decreased the contribution of contraction to wound closure. Day 32 after wounding, contraction contribution to wound closure amounted to 57.7%+/- 4.7% and 80.4%+/- 3.2% (mean +/- standard error of the mean, p < 0.005) of the initial wound areas, respectively, for lyophilized cell lysate-treated and phosphate-buffered saline solution-treated wounds. At this time of wound healing, the thickness of the dermis was increased 1.7-fold by the keratinocyte cell lysate treatment, but neither epithelial migration from the wound edges nor the thickness of the regenerated epithelium were significantly affected. In conclusion, in diabetic (db/db) mice the application of lyophilized cell lysate from cultured human keratinocytes influenced the healing of the dermis and wound contraction, but had no effect on reepithelialization.
