BACKGROUND: Whehter estradiol (E2) can change the expression of peroxisome proliferator-activated receptor gamma-2(PPAR-γ2) during differentiation of bone marrow stroma cells should be studied further.OBJECTIVE: To investigate the effects of 17β-estradiol (E2) on the gene expression of PPAR-γ2 mRNA and PPAR-γ2 protein.DESIGN: Contrast observational trial.SETTING: Laboratory Department of People's Hospital of Deyang City; Laboratory Center of Chengdu Military Command General Hospital and Chengdu Bai'ao Biol-Tech Limited Company.MATERTALS: A 3-month-old female SD rat (200±20) g used to isolate bone marrow stromal cells was obtained from Animal center of Chengdu Chinese Medicine University (Medical Experimental Animal Number 11). Dulbecco's mimimum essential medium (DMEM) was obtained from Hyctone Compnay. 1α, 25(OH)2D3, dexamethasome (DEX) and E2 were purchased from Sigma Company. Total RNA kits were obtained from Omga. One step RNA PCR kit (AMV) was obtained from Takara Shuzo Co, Ltd. Northern direct HRP labeling and detection kit was purchased from PIERCE. Western blotting luminol reagent was obtained from Santa cruz.METHODS: The experiment was carried out from April 2001 to July 2002 in the Laboratory Department of People's Hospital of Deyang City, Laboratory Center of Chengdu Military Command General Hospital and Chengdu Bai'ao Biol-Tech (0, 0.1, 10, 1 000 n) was used to interfere cell differentiation for 3 days. Cultured cells were crushed with Tris-Triton X-100 PBS; activity of alkaline phosphatase was detected with Beckman CX-7 biochemical analytical device; effect of 100 g/L formalin, stained with Weigert-hematoxylin for 10 minutes, rinsed with water, differentiated with 5 g/L hydrochloric ethanol, stained with Van Gieson, desiccated with ethanol of the fractional volume of 0.95, cleared with dimethylbenzene with RT-PCR, Northern blot and Western blot during cell differentiation.protein.proliferated within 24-72 hours. Cells shaped as triangle, multiple angles and fusiform. Three days later, volume of adherent cells was increased and colony, and 10 days later, they confluenced. Bone marrow stroma cells in many generalight red to yellow). Red plasma presented synthesis of collagen. The deeper the red was, the more the collagens were.pression of PPAR-γ2 mRNA was (4.0±0.4)%, (1.7±0.2)% and (2.8±0.2)% (t=6.1, 7.2, 11.5, P＜ 0.01), which was higher crease the expression of PPAR-γ2 protein. When concentration of E2 was 0.1, 10 and 1 000 nmol/L, expression of PPAR-γ2 protein was (2.2±0.2)%, (2.6±0.2)% and (4.1 ±0.2)%, which was higher than that in 0 nmol/L E2 group [(1.2±0.10)%, t=6.6, 8.5, 13.2, P＜0.01].CONCLUSTON: E2 can inhibit expression of alkaline phosphatase and promote differentiation of bone marrow stromal cells and expression of PPAR-γ2 mRNA and PPAR-γ2 protein.