Enhanced healing of cartilaginous injuries by N-acetyl-D-glucosamine and glucuronic acid

We investigated the restorative effect of orally administered glucose, N-acetyl-D-glucosamine (GlcNAc) and glucuronic acid (GlcUA) on the experimentally produced cartilaginous injuries in rabbits. A total of three holes in the left stifle joint, including one in the medial trochlear ridge, and two in the trochlear sulcus (proximal and distal) of articular cartilage were made surgically using a drill. For the control group, only tap water was administered daily and for the glucose, GlcNAc, GlcUA groups, a water based solution (1 g/head/day) of glucose, GlcNAc, glucuronolactone was administered daily, respectively. We observed the clinical symptoms daily and the condition of the injured part was observed macroscopically and histologically at 3 weeks after the operation. There was no difference in body weight or general conditions among each group. With respect to medial trochlear injury, 1/3 holes were not cured in the control, but all were cured in the glucose, GlcNAc and GlcUA groups, respectively. With respect to the proximal hole, 4/6 in the control group, 3/3 in the glucose and 2/3 in the GlcNAc were not cured. However, 2/3 in the GlcUA were cured. There was significant difference (p < 0.05) in the proximal holes between the control and the GlcUA. On the total points, there was significant difference (p < 0.05) between the control and GlcNAc or GlcUA. On histological examination, the injured parts were covered by fibrous connective tissues in the control and the glucose, whereas in the GlcNAc and GlcUA groups, the massive proliferation of matured cartilaginous tissues was observed, and the regenerated cartilaginous tissues were surrounded by the proliferation of chondroblast cells. In the regenerated tissue, matured cartilage substrate was also observed. Safranin O and Alcian blue stains marked a more significantly dense in the GlcNAc and GlcUA group than in the control (p < 0.01) in injured parts as well as in non-injured joint cartilage. (C) 2003 Elsevier Ltd. All rights reserved.