STUDIES ON GRANULATION TISSUE

Abstract

A morphological and biochemical study of granulation tissue in wound healing was reported, using the circular excised wound of the dorsal skin of male adult mice.Argyrophilic fibrils appeared first on the 6th day after the excision. After the 8th and subsequent days, prominent fibrogenesis was marked. Ribonucleic acid was most intensely demonstrated on the 8th and the 10th day. Alkaline phosphatase was observed only in the fibrotic area after the 8th day.Neutral salt soluble collagen may not integrate in the newly deposited argyrophilic collagen fibrils in the 8th day granulation tissue. The neutral salt soluble collagen would exist in a dispersed or submicroscopic fibrillar state in the granulation tissue.Acid soluble collagen might represent the bulk of newly deposited col-lagen fibrils.PAS positivity of collagen fibers gradually decreased with maturation of fibers.Biochemical study revealed that the neutral salt soluble collagen already appeared on the 6th day in considerable amounts. All collagen fractions gradually increased thereafter, and remarkable accumulation of insoluble collagen was recognized on the 10th and the 12th day. The ratio of neutral salt soluble and insoluble collagen to the total collagen changed inversely. Acid soluble collagen showed no remarkable change.The content of desoxyribo- and ribonucleic acid increased up to the 8th day and then gradually decreased in the granulation tissue.It has been shown that the incorporation of radioactive phosphorus into the nucleic acids made two peaks. The first was noted on the 4th day, when the leucocytic infiltration was prominent, and the second was on the 8th and the 10th day, when the active proliferation of fibroblasts and synthesis of collagen precursor were remarkable.The possible significance of these results is discussed.