A transparent chamber for the dorsal skin fold of athymic mice.

A transparent chamber designed for insertion in the dorsal skin fold of athymic mice is described. The chamber is based on ingrowth of a layer of granulation tissue from the surrounding subcutis of the animals. The thickness of the tissue layer in the chamber is accurately given by an exchangeable chamber component and the construction allows repetitive access to the tissue inside the chamber. A freely movable skin flap is prepared surgically on the back of the animals, and the chamber is inserted in this flap in a second operation about 2 weeks later. In the absence of air bubbles, infectious foci and excessive adipose tissue in the chamber, ingrowth of granulation tissue is completed 2-4 weeks after the insertion. When infections of the skin enclosing the chamber and atrophy of the skin flap are prevented, the functioning time of the transparent chamber is determined by the life span of the animals. In the present study the athymic mice remained healthy for 4-5 months after insertion of the chamber although they were kept under conventional conditions, but were given antimicrobial covering. Since athymic mice accept some human xenografts, both normal tissues and neoplasms, vital microscopical studies of such xenografts implanted into the chamber can be performed. Preliminary results of such studies on a human malignant melanoma are presented.