Treatment of mouse muscular dystrophy with the protease inhibitor pepstatin.

Dystrophic mice were treated for 5 weeks beginning at 3 weeks of age with 20 ugm per day of pepstatin, a potent inhibitor of cathepsin D. Mortality was less and weight gain greater in pepstatin treated mice than in controls. Muscle bulk was greater and hind lamb contractures were reduced in treated mice. Mean muscle fiber mass was significantly increased by pepstatin treatment. Inhibition of muscle protease may be the mechanism by which pepstatin slows the tempo of progression of mouse muscular dystrophy.