The effects of radiofrequency hyperthermia on type II collagen formation in the osteoarthritic knee

Abstract

Objective: To explore the effect of radiofrequency hyperthermia on type II collagen expression in a rabbit model of osteoarthritis (OA).

Methods: Experimental model of knee OA was replicated in the right hind limbs of 54 male rabbits by using modified Hulth modeling method. The rabbits were randomly divided into Model group, Lugua Polypeptide group and Radiofrequency Hyperthermia group. After modeling, Lugua Polypeptide group was given intramuscular injection of Lugua polypeptide; Radiofrequency Hyperthermia group was treated with radiofrequency hyperthermia; Model group was not given any special treatment. On the 7th, 13th and 19th day after radiofrequency hyperthermia, six experimental rabbits were chosen from each group and sacrificed to take out medial femoral condyle cartilages in the right hind limbs. Modified Mankins rating was applied to the morphological evaluation. Meanwhile, quantitative real-time PCR was used to detect the content of type II collagen in cartilage tissues of medial femoral condyle.

Results: At each time point after treatment, Mankins scores were decreased in all the 3 groups, with that of Model group significantly higher than those of the other two groups (Model group > Lugua Polypeptide group > Radiofrequency Hyperthermia group). The contents of type II collagen in cartilage tissues were increased in all the 3 groups, with that of Radiofrequency Hyperthermia group significantly higher than those of the other two group (Model group < Lugua Polypeptide group < Radiofrequency Hyperthermia group). The difference between groups was of statistical significance (p < .05). For Radiofrequency Hyperthermia group, Mankins scores were decreased gradually as the treatment time went by, with the content of type II collagen in cartilage tissues increased. The difference between time points was of statistical significance (p < .05).

Conclusions: Radiofrequency hyperthermia is superior to Lugua polypeptide in the treatment of knee OA, at least in rabbits. Its therapeutic mechanism may be related to the significant increase in type II collagen in cartilages.