OBJECTIVETo study the effects of zuogui pill (ZP) contained serum on the gene expressions of type-II collagen and proteoglycan during the differentiation of mesenchymal stem cells (MSCs) towards chondrocytes.

METHODSMSCs isolated from rat bone marrow were in vitro induced differentiation towards chondrocytes and stimulated with high- (57 g/kg), middle- (28.5 g/kg), and low-dose (9.5 g/kg) ZP contained serums and serum of blank rats. The proliferation of MSCs was analyzed by CCK-8 method. The 3rd-passage MSCs were divided into the blank control group (by adding serum of the blank group rats), the induction control group (by adding the induction fluid and serum of the blank group rats), and the ZP contained serum group (by adding the induction fluid and middle-dose ZP contained serum). The expressions of type-II collagen and proteoglycan were determined using reverse transcriptase PCR, Real-time PCR, and immunohistochemistry.

RESULTSCompared with the blank control group, the proliferation of MSCs could be promoted by ZP contained serum at different doses (P < 0.05), with the most obvious effect shown in the middle-dose ZP contained serum group (P < 0.05). The mRNA and protein expressions of type-II collagen could be identified in the induction control group and the ZP contained serum group on the 21st day of the induction. Of them, the mRNA expression of type-II collagen in ZP contained serum groups was obviously higher than that of the induction control group. Results of Real-time PCR showed that on the 21st day of the induction, the mRNA expression quantitation of proteoglycan in ZP contained serum groups was about 16-fold and 3-fold of the levels on the 7th day and the 14th day (P < 0.05), obviously higher than those of the induction control group (P < 0.05).

CONCLUSIONZP contained serum could induce MSCs proliferation, the gene expressions of type- II collagen and proteoglycan, which might be one of its molecular bases for protecting the cartilage.