[Induction of granulomatous liver inflammation by noninfectious particles]

A single intravenous injection of 0.1 mg/g of zymosan led to the formation of granuloma-type clusters of mononuclears in the liver of CBA mice or (CBA X C57B1)F1 hybrid mice. The area occupied by the granulomas grows for 3 to 9 days and then gradually diminishes so that the granulomas disappear practically in one month. Hydrocortisone injected in a dose of 125 mg/kg 2 and 24 hours before or 2 and 24 hours after zymosan inhibited the initiation of granulomas but, at the same time, led to their slower involution. Mice with zymosan-induced granulomas became hypersensitive to the derivate of an endotoxin--prodigiosin, a polysaccharide obtained from S. marcescens. After intravenous infusion of a preparation of corpuscular alkaline phosphatase (CAP) granuloma-like structures also appear in the liver of rats. In distinction from zymosan-induced granulomas they persist for a much longer time (up to 27 weeks). The first signs of CAP-induced granulomas appear in 3 days. The liver per cent by volume occupied by the granulomas gradually doubles by the 15th week and then reduces. At the same time, the number of granulomas per 1 mm3 of hepatic tissue remains practically constant for 3 to 21 weeks from the moment of the induction by CAP. Their average size grows slowly and reaches maximum by the 15th week, with significant variations. Desmine and reticular fibres accumulate in the granulomas, which is evidence of active involvement of hepatic fat-accumulating cells in their formation. The results show that resident macrophages are the triggers of granulomatous inflammation of the liver.