Valproate reduces collagen and osteonectin in cultured bone cells

Highlights • The long-term side effects of valproate can include bone loss, although the exact mechanism for this is currently unknown. • Here we show that valproate treatment reduces collagen I and osteonectin in an osteoblast-like cell line. • Collagen I is the main protein in bone matrix and osteonectin has a major role in bone development and mineralisation. • Reduced levels of these proteins may contribute to bone loss following long-term in vivo exposure to valproate.