HISTOLOGICALLY DEMONSTRABLE BOUND LIPID APPARENTLY ASSOCIATED WITH RELATIVELY STABLE MATURE COLLAGEN FIBRES

An extracellular material of connective tissues, having properties of bound lipid, can be stained by a saturated solution of Sudan black dissolved in acetone, following prior extraction in a solution of chlorofrom, methanol and hydrochloric acid for 24-48 h at 20°C or 37°C. This material cannot be demonstrated histologically in young, developing, soft connective tissues, but it is intensely Sudanophilic, and of widespread occurrence, in mature fibrous, connective tissues. In contrast to this, it is restricted to collagen fibres in areolar connective tissue, its distribution is patchy in fibrous connective tissues known to have a high rate of turnover, and it cannot be demonstrated in areas from which connective tissues have been resorbed. It is strongly stained in immature and mature bone, and in cemcntum and dentine. The role of this material in connective tissues is unknown, but it appears to be associated with mature, relatively stable, collagen fibres. © 1969 S. Karger AG, Basel.