Prostatic tumor (R3327) skeletal metastasis.

Male Copenhagen rats were inoculated with monodispersed R3327-MatLyLu prostate tumor cells via the tail vein under concomitant temporal occlusion of the inferior vena cava to develop an animal model for skeletal metastasis of prostate cancer. This procedure reproducibly resulted in metastatic tumor growth in the lumbar region of the vertebral column. Microscopically, tumor growth became visible in the fifth and sixth lumbar vertebrae within 4 days after inoculation. Clinical signs of nerve function disablement (hind leg paresis and paralysis) followed within 14 days of such a procedure. Cell culture technique confirmed the presence of a viable, proliferating tumor cell population within the spinal canal of the fifth and sixth lumbar vertebrae. Histologically, a clear response of osteoclastic and concomitant osteoblastic activities was observed in the lumbar spinal column. In the serum, a transient phase of hypercalcemia could be demonstrated. The development of skeletal metastases in these animals was not reflected by significant alteration in serum levels of acid phosphatase, prostatic-specific antigen, or osteocalcin. These observations support the concept of the vertebral venous plexus being involved in the dissemination of prostate tumor cells. The surgical procedures described permit experimental investigations of bone metastasis of prostatic cancer.