Beta-ecdysone (Ecd) prevents the metabolic syndrome in ovariectomized (ovx) rats: joint cartilage tissue

We have recently shown that Ecd prevents osteoporosis and decreases visceral fat mass in ovx rats. This animal model is known to develop a metabolic syndrome and this disease was shown to be associated with increased visceral and bone marrow fat tissue. The adipocytes in bones secrete large amounts of cytotokines which have cytotoxic effects on osteoblast thereby augmenting estrogen deficiency induced osteoporosis. The reduction of bone mass by Ecd is suggestive that fat load in the knee joints – the Hoffa's fat pad – are also reduced thereby exerting preventive effects on osteoarthritis.

Ovx rats (n=10–12 per group) were orally treated with Ecd (56mg/day/animal) and the amount the size of the knee joint fat depot as well as the knee joint height of cartilage tissue were determine histomorphometrically following 4 weeks of treatment. Control rats received soy free food, positive controls received estradiol-17β (E2; 0.108mg/animal/day) supplemented to the chow.

The size of the knee joint cartilage tissue was significantly lower in ovx and higher in E2 and Ecd treated animals while the Hoffa's fat pad was significantly larger in ovx than in E2 and Ecd treated animals.

These results suggest that the high fat load in the knee joint is a source of high cytokine production which exerts inhibitory effects on development of cartilage tissue in the knee joint. Both, E2 and Ecd seemed to prevent these lipotoxic effects.

Acknowledgement: This work was in part funded by VerdeVital GmbH