Patterns of activation and inhibition of fibrinolysis in the normal skin of rat, guinea pig, and rabbit.

The distribution and intensity of fibrinolytic activity and of inhibitors of fibrinolysis in the normal skin of the rat, guinea pig and rabbit were studied with histochemical techniques. Rat skin exhibited the highest overall fibrinolytic activity and rabbit skin the lowest, with guinea-pig intermediate. The distribution of fibrinolytic areas differed in the different species. The fibrinolytic activity was caused by an activator of plasminogen related to the blood vessels or in some instances (mainly in the rabbit) to the epidermis. The ability to inhibit plasmin was highest in guinea pig skin and lowest in rat skin, with rabbit skin intermediate. In all 3 species the inhibition was related chiefly to the muscular layer. Epidermis was an additional source of inhibition.