Dimethyl sulfoxide. Biomechanical effects on tendons.

Forty-eight mice were treated for 12 time periods from 0 days through 28 days at 24-hour intervals by rinsing the skin area of the Achilles tendon of each hindleg with 100 microliters of a solution of 70% drug grade dimethyl sulfoxide in 30% sterile water. After the treatment period the mice were killed and the Achilles tendons were subjected to separation force analysis to determine tensile strength. The mean separation force was shown to be a function of the treatment period (P = 0.0294) with a significant linear component (P = 0.0049), a significant quadratic component (P = 0.0036), and a significant cubic component (P = 0.0049). The model identified an initial area of decreasing mean separation force (0 to 7 days), an area of increasing mean separation force (7 to 22 days), and a subsequent area of decreasing mean separation force (22 to 28 days). The maximum decrease in the group mean separation force was 20.2% and was observed in the 7-day treatment group. The clinical significance of the results of this study was that the topical application of dimethyl sulfoxide was associated with periods of decreased mean separation forces in tendons. The avoidance of vigorous muscular activity is recommended during therapy with dimethyl sulfoxide.