Cartilage damage by a granulomatous reaction in a murine species

The encapsulation of intact rat femoral head cartilage or discs of bovine nasal cartilage with cotton-gauze before implantation in the subcutaneous tissues of mice, results in an accelerated loss of cartilage proteoglycan. Loss of proteoglycan from bovine nasal cartilage occurred later than rat femoral head cartilage, but eventually brought about complete dissolution of the cartilage. Freeze-thaw killing of bovine nasal cartilage did not alter the amount of proteoglycan lost. Destruction of both femoral and nasal cartilage was related to the mass of cotton implanted and to the growth of connective tissue within the implanted cotton. Mice previously implanted with femoral head cartilage were able to show enhanced degradation to new implants; this was even greater if the original implants were encapsulated with cotton. Presoaking of cotton-cartilage implants with the non-specific irritant, carrageenan inhibited the breakdown of cartilage. Autoradiographs of 35sulphate pulsed femoral cartilage following implantation with cotton showed reduced incorporation of radiolabel by chondrocytes.