Inhibition of bone resorption in culture by (+)-catechin

A pretreatment with (+)-catechin renders embryonic mouse calvaria in culture resistant to the action of bone resorbing agents, either parathyroid hormone (PTH), prostaglandin E2 or retinoic acid, and inhibits in a parallel way the enhanced excretion of N-acetyl-beta-glucosaminidase, a reference lysosomal enzyme, induced by these agents; it has, however, no effect on the small spontaneous leakage of lactate dehydrogenase from the explants. Moreover, the resorption induced in calvaria by a pretreatment with PTH or retinoic acid is inhibited by a further culture with catechin. This inhibition of bone resorption is discussed in relation with the collagen-stabilizing properties of (+)-catechin.