[STUDY OF CHONDROCYTE PROLIFERATIVE ACTIVITY IN THE CANINE ARTICULAR CARTILAGE DURING LENGTHENING OF THE ADJACENT LIMB SEGMENT].

To assess the effect of orthopedic lengthening on proliferative activity of chondrocytes in the articular cartilage, dosed tibial lengthening by 28 mm was performed in 15 dogs at the rate of I mm/day divided into 4 sessions. Experiment time-points - 28 days of distraction, 30 days of fixation in the apparatus and 30 days after the apparatus removal. Methods of light microscopy of paraffin sections, immunohistochemistry, histomorphometry of semithin epoxide sections were used. At the end of distraction, the preferential concentration of Ki-67 marker was detected in the upper layers of the intermediate zone, while focal distribution was noted in the superficial and deep zones of articular cartilage of femoral condyles. Upon completion of lengthening, a stable increase in the number of chondrocytes was noted in the superficial and intermediate zones but not in the deep cartilage zone as com ared with the intact group (n=5).