Increased lability of lung collagen crosslinks

Lung parenchymal collagen is highly insoluble, contributing to the architecture and tensile strength of the lung. Insufficient quantities of collagen are extractable by conventional procedures to permit detailed analyses of collagen types and elucidation of injury to the lung. Sonic bursts at low power release monomer collagen chains from purified tropocollagen fibers. This communication describes sonication procedures at pH 5.2 and 3.0 which release approximately 4 and 15%, respectively, of soluble collagen from lung parenchymal tissue. These quantities are approximately 40 and 140 times greater than are obtained by conventional dilute acid solubilization. The soluble chains are apparently intact and suitable for sensitive determinations which will enable investigators to elucidate the composition of lung collagen fibers.