ISSN: 2161-1149 (Printed)
Objective: The purpose of this study was to demonstrate the histological changes occurring in the synovium and meniscus after transection of the anterior cruciate ligament in rabbits, and to evaluate these changes after intraarticular injection of sodium hyaluronate.
Methods: Fifteen rabbits were divided into three groups. The surgery was performed in the left knees only and the right knees served as controls. Group (I) served as sham-operated controls, Group (II) underwent unilateral anterior cruciate ligament transection of the left knees and received no treatment, and Group (III) received intra-articular injections of 0.3 ml sodium hyaluronate into the left knee beginning 1 week after surgery, once a week for 5 weeks. All rabbits were killed 8 weeks following surgery for assessment of knee meniscus by histological, histochemical and ultrastructural analyses.
Results: The histological examination of group II demonstrated the synovium with multilayered synovioblasts, and extensive cellular and matrix deterioration of meniscus in the form of altered cell distribution, decreased cell density, and abnormalities in the collagen arrangement. In groups III, the synovium showed many blood vessels and the cells of menisci apparently increased. Histochemically, safranin-O staining revealed the increased presence of proteoglycan in the sodium hyaluronate treated menisci relative to non-treated one. Ultrastructurally, the chondrocytes of group II showed obvious decrease in their organelles associated with the synthesis and secretions of the matrix with an increase in the number of lysosomes and cytoplasmic vacuoles. In group III, some active chondrocytes containing RER and ribosomes were observed.
Conclusions: The results in the present study documented that the treatment with sodium hyaluronate after anterior cruciate ligament transection, induced an improvement of several structural features of both synovial membrane and meniscus.