The effect of low molecular weight chitosan on bone resorption in vitro and in vivo.

Abstract

We studied the effect of low molecular weight chitosan (LMWC) on the formation of osteoclast-like multinucleated cells (OCLs) in the co-culture of mouse osteoblastic cells and bone marrow cells in the presence of 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3]. LMWC at 440 microg/ml inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive OCLs induced by 1alpha,25(OH)2D3. We prepared OCLs in the co-culture of osteoblastic cells and bone marrow cells. The effect of LMWC on pit formation by OCLs was examined using dentin slices, and LMWC inhibited pit formation at 440 microg/ml. Oral administration of the LMWC to ovariectomized rats prevented a decrease in bone mineral density (BMD) of the lumbar vertebra without affecting the body and uterus weights. These results suggested that LMWC prevented a decrease in BMD in vivo by inhibiting osteoclastic bone resorption.