Cellular activation following injury of the kidneys

Summary

On the third day after partial unilateral extirpation of the kidneys, there was a rise of mitotic activity, hypertrophy of the cells and their nuclei and a rise of the RNA and DNA content in the cells. Cellular activation during healing of the kidney wound occurred not only in the regenerating organ, but also in the intact one on the contralateral side. Activation of the cells in wound healing is connected with the action of products of tissue protein disintegration. Administration of a renal tissue extract caused a marked increase of mitotic activity, hypertrophy of the cells and a rise of nucleic acid content. This reaction is organ specific in character. The renal extract stimulated the mitotic activity of the kidney alone, whereas hepatic and pancreatic extracts had no effect on this activity in the kidney.

The second factor involved in cellular activation during wound healing was the compensatory increase of the organ function. With complete removal of one of the kidneys, an increase of mirotic activity and cellular hypertrophy and a rise of the RNA and DNA content were noted in the intact kidney. The effect of the second activation factor was manifested at a later stage, when the function of the injured organ was retuming. With complete removal of one of the kidneys, a rise of mitotic activity in the intact kidney became manifest only on the 7th day after the operation.