Phosphatidylcholine-specific phospholipase C gamma 1 (PLC gamma 1) is involved in regulating cell metabolism. However, little is known how PLC gamma 1 directs BMSC differentiation. Here, we investigated the role of PLC gamma 1 in rat BMSC differentiation into osteoblasts and chondrocytes. The results of Alizarin red and Alcian blue staining showed that PLC gamma 1 inhibitor U73122 significantly enhanced the mineralization capacity and proteoglycan deposition of BMSCs. The results of qPCR technique and Western blot analysis showed that long-term treatment of U73122 enhanced COL1A1 and OPG mRNA levels and Collagen 1A1, BMP2, and p-Smad1/5/9 protein levels and that short-term treatment of U73122 enhanced COL2A1 and SOX9 mRNA levels and Collagen 2, SOX9, Aggrecan, TGF-beta 3, and p-Smad2/3 protein levels. Decreased p-mTOR and pP38 contributed to enhanced osteogenic potentials of BMSCs and increased p-P38 contributed to enhanced chondrogenic potentials of BMSCs. The scaffold transplantation with U73122+BMSC was more efficacious than BMSC alone for osteochondral defect repair in a rat model. Therefore, suppressing PLC gamma 1 could improve the capacity to effectively use BMSCs for cell therapy of osteochondral defect. (C) 2020 The Authors. Published by Elsevier Inc.