Differences in the molecular weight of sodium hyaluronate for osteoarthritis: benefits and mechanisms / 中华骨科杂志

ABSTRACT

Sodium hyaluronate is one of the natural components of articular cartilage and synovial fluid,which plays important roles in maintaining the structure and physiological functions of joints.Abnormal change of the content and physicochemical properties of sodium hyaluronate in the joints is one of the common pathological causes of osteoarthritis.Supplementation of exogenous sodium hyaluronate,which has similar physical and chemical properties as those in normal joints,has been considered as an effective strategy for clinical treatment of osteoarthritis.However,the benefits of intra-articular injection of sodium hyaluronate are still under debates.Moreover,different recommendations for clinical use were developed in several clinical guidelines.Several guidelines suggested that molecular weight of sodium hyaluronate was an important factor influencing the clinical benefits in osteoarthritis.Diverse products of sodium hyaluronate present different physicochemical and biological characteristics,which may lead to differences in clinical efficacy and safety.High-molecular-weight sodium hyaluronate,with highly modified and cross-linked sugar chains,potentially differ from those with low molecular weight in physicochemical properties,rheological characteristics,and physiological activities.In general,high-molecular-weight sodium hyaluronate have higher viscosity and elasticity.The exogenous hyaluronate,of which the molecular weight is similar to those in normal joints,probably have the similar rheological characteristics.A large number of clinical studies demonstrated that sodium hyaluronate products with high-molecular weight significantly relieved joint pain and improved joint functions in patients with osteoarthritis.In contrast,the clinical efficacy of the low-molecular-weight hyaluronate is still controversial,because several studies could not establish the superiority in osteoarthritis when comparing with the placebo.Studies on molecular mechanisms revealed that some physiological functions of sodium hyaluronate were molecular-weight dependent.High-molecular-weight sodium hyaluronate may have more pronounced impacts on the regulation of inflammation and maintaining the homeostasis of extracellular matrix.This review focused on the effects of sodium hyaluronate with different molecular weight in treating osteoarthritis.Evidence based on clinical studies related to the molecular-weight differences of sodium hyaluronate were presented.Furthermore,the optimal use of various products of sodium hyaluronate with different molecular weight was discussed.