THE ORIGIN AND MODE OF FIBROBLAST MIGRATION AND PROLIFERATION IN GRANULATION-TISSUE

The factors which regulate the properties of granulation tissue remain uncertain. The key cells in granulation tissue are fibroblasts and th eir role was investigated in rat skin excisional wounds. Full thicknes s wounds in 28 Hooded Lister rats were made and traced. On days 1 to 7 , animals in groups of 4 received colchicine 1 mg/kg subcutaneously, 4 h before being killed. Wound sections were stained to locate and coun t mitotic cells. All wounds healed with a normal coefficient of contra ction. The fibroblasts' mitotic indices (% of mitotic cells) were calc ulated. Dermis: 0.1% vs. 2.9% (control vs. test P < 0.001, paired t-te st); fascia; 0.07% vs. 5.6% (control vs. test P < 0.001); granulation tissue: 9.7%. Granulation tissue fibroblasts come mainly from the adja cent fascia although the dermis may have an initial role. Once they ar e in the wound replication is extremely rapid. This study highlights f or the first time the rapidity of fibroblastic migration and prolifera tion in excisional wounds, and suggests that future therapeutic interv entions to control granulation tissue should consider these kinetics.