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| 自然衰老大鼠骨组织中TERT变化与骨衰老相关性的研究 |
| The study of the relationship between TERT change with aging and bone in rats |
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| DOI：10.3969/j.issn.1006.7108.2015.12.002 |
| 中文关键词: 大鼠 骨 端粒酶逆转录酶 衰老 |
| 英文关键词:Rat Bone Telomerase reverse transcriptase Aging |
| 基金项目:国家自然科学基金（81302986);福州市卫生系统科技项目（2013-S-wt3,2013-S-wq8) |
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| 中文摘要: |
| 目的 探讨在衰老过程中骨组织的端粒酶逆转录酶（telomerase reverse transcriptase，TERT)及其相关因子随增龄的变化情况。方法 6月龄、10月龄、13月龄、18月龄SD大鼠各20只（雌雄各半），取左侧完整股骨按组别、性别排列整齐,Discovery Wi双能X线骨密度仪测定股骨BMD,采用东芝800MA平板DR摄片机进行X线摄片。取大鼠右侧股骨近端骨组织行HE染色及图像分析。采用酶联免疫吸附法（ELISA)检测血清中的骨钙素（osteocalcin,BGP)、抗酒石酸酸性磷酸酶5b(tartrate- resistant acid phosphatse 5b，TRACP5b)、雌二醇（estradiol,E2)、睾酮（testosterone，T)含量。采用实时突光定量 SYBR GREEN 法检测第1腰椎中TERT、雌激素受体α(estrogen receptorα,ERα)、mRNA表达。采用Western Blot检测第2腰椎TERT、ERα蛋白的表达。结果 ELISA法检测结果显示大鼠血清中BGP、E2、T水平均随着月龄增大逐渐降低，TRACP5b水平均随着月龄增大逐渐升高（P<0. 05);骨组织中Erα、TERT的mRNA与蛋白表达均随月龄的增长而降低，各组间比较有显著性差异（P < 0. 05)。骨密度检测结果显示：雌性大鼠股骨BMD随着月龄增大呈下降态势，且除6月龄外其他月龄雌性均低于同期雄性组 (P<0.05)o雄性BMD均值随着月龄增大呈下降态势，但6月龄与10月龄相比、13月龄与18月龄相比无统计学意义（P >0.05）。HE染色结果显示6月龄组股骨头骨小梁宽厚且量多稠密，分布均勻，排列规则，相互之间连成网状，未见有骨小梁中断；10月龄之后，骨小梁相对细小，小梁间距较宽，但排列整齐，且雌性较雄性更为明显，13月龄及18月龄组随着月龄增大骨小梁更加纤细，分布稀疏散乱,骨小梁中断多见，小梁间距增大，甚至出现典型骨质疏松松质骨的病理形态改变，且雌性较雄性更为明显。结论 大鼠在增龄过程中，体内性激素水平下降的同时，骨组织内TERT转录水平降低,端粒酶活性下降，使骨组织中骨形成功能衰退，骨形成低于骨吸收，从而导致骨衰老。 |
| 英文摘要: |
| Objective To explore the change of telomerase reverse transcriptase (TERT) expression and related factors in the bone during natural aging process. Methods SD rats of 6 months, 7 months, 10 months, and 15 months of age, each 20 with 10 males and 10 females，were selected. The whole left femurs were collected and arranged in neat rows by group and gender. X-ray films were performed using Toshiba 800MA flat-panel DR radiography machine. Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry (DXA). The right proximal femurs were stained using HE method and the images were analyzed. Serum osteocalcin (BGP)，tartrate -resistant acid phosphatase 5b (TRACP5b)，estradiol (E2) , and testosterone (T) were examine using enzyme-linked immunosorbent assay. The mRNA expression of TERT and estrogen receptor α(ERα) in L1 was detected using SYBR GREEN real time quantitative assay. The expression of TERT and Erα protein was detected using Western blotting. Results BGP, E2，and T levels in rats serum gradually decreased with the growth of age, but TRACP5b increased gradually with age (P < 0. 05). Erα and TERT mRNA and protein expression in the bone tissue reduced with age growth (P<0. 05). The BMD in female rats decreased significantly with aging，and it was lower than that in male rats a same age except in 6 - month rats (P < 0. 05). BMD in male rats showed a trend of decline with aging，but there was no difference between 6 - and 10 - month rats, and between 13 - and 18-month rats (P >0. 05). In HE staining，bone trabecular in the femurs of 6 - month rats was thick and dense, uniformly distributed, regularly arranged, and mutually linked. There was no trabecular disconnection. In 10 - month rats，the trabecular bone was relatively small, trabecular spacing was wide, but it was arranged in rows，and it was more significant in females than in males. In 13-month and 18-month rats, the trabecular bone was more slender and sparsely scattered distribution. The trabecular bone disruption was seen more often，the trabecular space increased，and even typical osteoporotic cancellous bone appeared. It was more obvious in the females than in males. Conclusion In natural aging process, while estrogen levels decline, the transcriptional level of TERT reduces in bone tissue，the telomerase activity decreases，and bone formation is lower than the bone resorption, resulting in the bone aging. |
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