Cutaneous reepithelialization and wound contraction after skin biopsies in rabbits: a mathematical model for healing and remodelling index

The objective of this study was to develop a standard operating procedure for the analysis of skin wound healing using histomorphometrical measurements and mathematical data analyses. The mathematical model is derived from observations of normal cutaneous healing in the rabbit. It is designed to allow a simple scoring of the major steps of healing and remodelling. Full-thickness punch biopsies were performed on the skin of the back of New Zealand-white rabbits and healing was analyzed by histopathological examination after 2, 5, 9 and 14 days, using different staining techniques. Histomorphological measurements were also made. The thickness of the epidermis and neo-epidermis were compared. Several indices relative to wound severity and contraction were computed in an attempt to defi ne a global healing index. A remodelling index was calculated based on a colorimetric analysis with Mallory Trichrome staining and hair migration. The changes in indeks values seemed to correlate with the histopathological analysis. No material flaws appeared when this model was applied to the natural healing process. This model was developed for scoring and accurate comparative evaluation of the effects of various treatments, biomaterials or pharmacological preparations on soft tissue healing and remodelling in rabbits. Although the healing of cutaneous wounds in rabbits differs from that in humans, this model may still be relevant for screening new wound healing preparations.
Cilj ovog istraživanja je razvijanje osnovne metode za analizu zaraštavanja kože služeći se histomorfometrijskim mjerenjima i matematičkom analizom podataka. Matematički je model nastao promatranjem fi ziološkoga zarastanja kože u kunića. Model je razvijen za jednostavno mjerenje osnovnih faza zarastanja i remodeliranja rane. Potpuna biopsija kože provedena je na leđnoj koži novozelandskih bijelih kunića te je analiza zarastanja promatrana histopatološki nakon drugoga, petoga, devetoga i četrnaestoga dana rabeći različite metode bojenja. Također su izvršena histomorfološka mjerenja. Uspoređene su vrijednosti debljine fi ziološkoga i novonastaloga epidermisa. Nekoliko indeksa povezanih sa zarastanjem i kontrakcijom kože pribrajani su s pokušajem utvrđivanja potpunoga indeksa zaraštavanja. Kolometrijska analiza s Mallory trichrome bojenjem korištena je za izračun remodelirajućega indeksa i promatranja migracije dlačnoga folikula. Promjene u vrijednosti indeksa mogu se povezati s histopatološkom analizom. Prirodni proces zarastanja promatran je bez utjecaja čimbenika koji mogu doprinijeti ishodu samoga zarastanja. Taj je model razvijen kako bi se moglo promatrati i uspoređivati različita liječenja, biomaterijali i farmakološki pripravci za zarastanje i remodeliranje mekoga tkiva u kunića. Unatoč razlici u zarastanju kože kunića i čovjeka, ovaj model može biti koristan za promatranje novih pripravaka za zaraštavanje rana.