Connective tissue reactions to lambda-carrageenan in the rat: Lambda-Carrageenan-Collagen Interaction

The development of the λ-carrageenan granuloma in the rat has been quantitatively examined. The wet weight, weight after freeze-drying and ether extraction, and the amount of DNA per granuloma reached a maximum twice: the first one within three days, the second maximum at the sixth day. They probably represent the maximal nonproliferative and proliferative response to λ-carrageenan, respectively. Through labeling of the collagen of young rats with 3H-proline it was shown that after 12 days about 45% of the acid insoluble collagen, preexisting in the granuloma at the third day, was no longer present in the gelatin fraction, while simultaneously new acid insoluble collagen was formed. The total amount of collagen increased from 3 up to 30 days. This finding contrasts with the rapid decrease in the amount of collagen starting at about the 15th day in guinea pig granulomata provoked by commercial carrageenan preparations. In vitro, native acid soluble collagen from rat skin was precipitated with λ-carrageenan. From this precipitate the collagen was only partially extractable by gelatinization. Its implications for the figures on collagen extracted from the granuloma were discussed.