摘要：
背景:课题组前期研究结果显示黄精多糖具有抗骨质疏松作用,但对其在体内对去卵巢骨质疏松防治效果的分子机制知之甚少.目的:探究黄精多糖在体内对大鼠骨微结构、骨密度的作用以及对成骨、破骨相关基因mRNA表达的影响机制.方法:25只SPF级雌性未受孕的3月龄SD大鼠随机分为5组,假手术组(等体积生理盐水)、模型组,唑来膦酸盐组[0.2 mg/(kg?d)],高剂量黄精多糖组[800 mg/(kg?d)],中剂量黄精多糖组[400 mg/(kg?d)].除假手术组外均建立去卵巢大鼠模型.术后1周隔天灌胃相应药物,连续12周后将大鼠处死,取其子宫称质量,收集一侧胫骨行Micro-CT骨形态计量学分析,对侧胫骨提骨头RNA行q-PCR检测.结果与结论:①相较于假手术组,模型组大鼠体质量显著性增加而子宫质量明显降低(P < 0.05);与模型组相比,高剂量黄精多糖组和唑来膦酸盐组均能明显减缓体质量过快增加(P < 0.05);②模型组相较假手术组骨密度下降63%(P < 0.001),经过12周治疗,高剂量黄精多糖组与唑来膦酸盐组相较模型组骨密度均有所增加,分别增加44%和38%(P < 0.05),骨体积分数、骨小粱数量也有所增加(P < 0.05),骨小粱分离度明显降低(P < 0.05);③在体内,高剂量黄精多糖组能明显促进成骨分化相关基因碱性磷酸酶、RUNX2、Col1a1、骨钙素的表达而抑制破骨分化相关基因ACP5、CTSK的表达(P < 0.05),能明显抑制ACP5、CTSK的表达(P < 0.05);④结果说明,高剂量的黄精多糖能够减少去卵巢大鼠的骨丢失、骨密度下降,改善骨微结构破坏,促进成骨相关基因而抑制破骨相关基因mRNA的表达.%BACKGROUND: Previous studies have found that polygonatum sibiricum polysaccharide (PSP) exhibits anti-osteoporosis effect, but its therapeutic effect in ovariectomized osteoporotic rats and the molecular mechanisms are poorly understood. OBJECTIVE: To investigate the effect of administration of PSP on the bone microstructure, bone mineral density as well as osteoblast- and osteoclast-related gene expression in rats. METHODS: Twenty-five infertile female Sprague-Dawley rats aged 3 months were randomly allotted into five groups (n=5 per group): sham operation (same volume normal saline), model, zoledronate (0.2 mg/kg?d), high-dose PSP (800 mg/kg?d) and medium-dose PSP (400 mg/kg?d) groups. All rats were subjected to ovariectomy except sham operation group. The administration was intragastrically given every 2 days beginning at 7 days after modeling and lasted 12 weeks. Then, the rats were sacrificed, and the uterus was weighed. The bilateral tibias were removed, one side for histomorphometric analysis by micro-CT, and the other one for RNA detection by qualified PCR. RESULTS AND CONCLUSION: Compared with the sham operation group, the rat body mass in the model group was significantly increased and the weight of uterus was significantly decreased (P < 0.05). Compared with the model group, zoledronate and high-dose PSP could significantly alleviate the excessive increase in body mass (P < 0.05). The bone mineral density in the model group was decreased by 63% compared with the sham operation group (P < 0.01), Compared with the model group, after 12-week high-dose PSP and zoledronate administration, the bone mineral density was increased by 44% and 38%, respectively (P < 0.01); the trabecular bone volume fraction and trabecular number rose significantly(P<0.05),while the trabecular separation decreased significantly(P<0.05).In vivo,PSP could significantly promote the expression levels of osteoblast-related genes (alkaline phosphatase, RUNX2, Col1a1 and osteocalcin), and significantly inhibit the expression levels of osteoblast-related genes (ACP5 and CTSK) (P < 0.05). These results imply that high-dose PSP can reduce bone loss and decrease of bone mineral density, improve the destruction of bone microstructure, as well as promote osteoblast-related genes but inhibit osteoclast-related gene mRNA expression in the ovariectomized rats.
