GLYCOSAMINOGLYCAN CHANGES IN REGENERATIVE MENISCI OF THE IMMATURE RABBITS — HISTOLOGICAL AND SPECTROPHOTOMETRIC QUANTITATION

Abstract

Purpose: This study was conducted primarily to compare the contents and distribution of Glycosaminoglycan (GAG) in the normal and regenerated menisci, and partly to elucidate the role of GAG in the meniscus to fulfill its function. Method: A total of 60 immature rabbits, weighing 300–400 gm and aged 4 weeks, were used for the study. Total medial meniscectomy in the right knee joint was performed in all rabbits. The medial menisci of the left knee joints were used as control. After 16, 20, 24 and 28 weeks postoperatively, the amount of GAG in normal and regenerated menisci were measured. For the measurement of quantity and distribution of GAG contents, photon absorptiometry and Safranin O staining method were used. Results: (1) In 48 of the 60 medial meniscectomized knees, menisci were regenerated in various sizes with degenerative changes of joints, especially on tibial side. (2) In normal menisci, GAG was distributed at inner and middle 1/3, while GAG in regenerated menisci was diffusely found in the entire width. (3) The concentration of GAG per 1 mg of regenerated menisci were 4.36 ± 1.68, 4.58 ± 1.14, 4.65 ± 2.21, 4.60 ± 2.06 μg in each 16, 20, 24, and 28 week groups, while those of normal menisci were 9.10 ± 2.09, 9.75 ± 3.97, 11.80 ± 8.44 and 14.51 ± 8.91 μg. (4) In normal menisci, the amount of GAG was gradually increased as rabbit got older. However, there was no statistical differences of quantitative amount of GAG of regenerated menisci among the 16, 20, 24, and 28 weeks groups during the observation periods (p > 0.05). (5) There was a distinctive difference in Safranin O stainability by every 4 μg increase of GAG in both 1 mg of normal and regenerated menisci. Conclusion: This study showed the quantitative change of GAG between normal and regenerated menisci, and comparative analysis of GAG contents in the menisci by biochemical method and histological method were found to be useful tools.