目的 基于SIRT3介導(dǎo)成骨細(xì)胞凋亡通路分析茶多酚對骨質(zhì)疏松癥（OP）的干預(yù)作用和相關(guān)分子機制。方法 40只大鼠于后肢臀部im氫化可的松建立OP大鼠模型，將造模大鼠隨機分為模型組，茶多酚低劑、高（25、100 mg/kg）劑量組，阿侖膦酸鈉（1 mg/kg）組，每組10只，另取10只正常飼養(yǎng)的大鼠設(shè)為對照組。造模成功后第2周各組大鼠均給藥干預(yù)。采用Micro-CT分析大鼠骨密度（BMD）和骨微結(jié)構(gòu)；蘇木精–伊紅（HE）染色觀察大鼠股骨組織病理形態(tài)；ELISA法檢測大鼠血清骨代謝指標(biāo)和氧化應(yīng)激指標(biāo)；TUNEL染色檢測大鼠股骨組織細(xì)胞凋亡指數(shù)（AI）；Western blotting法檢測大鼠股骨組織中去乙?；?（SIRT3）、B淋巴細(xì)胞瘤2（Bcl-2）、B淋巴細(xì)胞瘤-2相關(guān)蛋白（Bax）表達(dá)。結(jié)果 與模型組比較，茶多酚25、100 mg/kg組大鼠骨組織病理損傷明顯減輕，大鼠BMD、骨體積分?jǐn)?shù)（BV/TV）、骨小梁數(shù)量（Tb.N）、骨小梁厚度（Tb.Th）、骨連接密度（Conn.D）均顯著升高，骨小梁分離度（Tb.Sp）顯著降低；血清堿性磷酸酶（ALP）、Ⅰ型前膠原氨基端前肽（PⅠNP）水平和超氧化物歧化酶（SOD）、谷胱甘肽過氧化物酶（GSH-Px）活性均顯著升高，Ⅰ型膠原羧基末端肽（CTX-Ⅰ）水平、丙二醛（MDA）含量均顯著降低；大鼠股骨組織AI、Bax蛋白表達(dá)量顯著降低，SIRT3和Bcl-2蛋白表達(dá)量顯著升高，差異均有統(tǒng)計學(xué)意義（P＜0.05）。茶多酚100 mg/kg組大鼠上述指標(biāo)均顯著優(yōu)于茶多酚25 mg/kg組，差異有統(tǒng)計學(xué)意義（P＜0.05）。結(jié)論 茶多酚可能通過調(diào)控SIRT3/Bcl-2信號通路調(diào)節(jié)骨代謝指標(biāo)水平、減輕氧化應(yīng)激、抑制成骨細(xì)胞凋亡，從而對OP產(chǎn)生良好的保護(hù)作用。

Objective The intervention effect of tea polyphenols on osteoporosis (OP) and related molecular mechanism were analyzed based on SIRT3 mediated osteoblast apoptosis pathway. Methods Forty rats were injected with hydrocortisone intramuscularly into the buttocks of the hind limbs to establish the OP rat model. The rats were randomly divided into model group, tea polyphenol low and high (25, 100 mg/kg) dose group, and alendronate sodium 1 mg/kg group, with 10 rats in each group. Another 10 normal rats were set as control group. The rats in each group were given drug intervention in the second week after successful modeling. Bone mineral density (BMD) and bone microstructure were analyzed by Micro-CT, HE staining was used to observe the pathological morphology of rat femur, serum bone metabolism and oxidative stress were detected by ELISA, TUNEL staining was used to detect the apoptosis index (AI) of rat femur, the expressions of d Sirtuin 3 (SIRT3), B-cell lymphoma-2 (Bcl-2), and B-cell-lymphoma-2 related protein (Bax) in rat femur were detected by Western blotting. Results Compared with model group, the pathological damage of bone tissue in tea polyphenol 25 and 100 mg/kg group was significantly reduced, and the BMD, BV/TV, Tb.N, Tb.Th, and Conn.D increased significantly, and Tb.Sp decreased significantly. The levels of ALP, PⅠNP, SOD, and GSH-Px increased significantly, while the levels of CTX-Ⅰ and MDA decreased significantly. The expression of AI and Bax protein in rat femur decreased significantly, while the expression of SIRT3 and Bcl-2 protein increased significantly, the difference was statistically significant (P < 0.05). Above indexes of rats in tea polyphenol 100 mg/kg group were significantly better than those in tea polyphenol 50 mg/kg group, and the difference was statistically significant (P < 0.05). Conclusion Tea polyphenols may regulate the level of bone metabolism, alleviate oxidative stress, and inhibit osteoblast apoptosis by regulating SIRT3/Bcl-2 signaling pathway, thus have a good protective effect on OP.

R965

張家港市青年科技項目(ZJGQNK201912)