Li Pei, Gan Yibo, Xu Yuan, Wang Liyuan, Ouyang Bin, Zhang Chengmin, Luo Lei, Zhao Chen, Zhou Qiang
Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
Department of Orthopedic Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
Int J Biol Sci. 2017 Jan 15;13(2):145-156. doi: 10.7150/ijbs.16770. eCollection 2017.
Accelerated cellular senescence within the nucleus pulposus (NP) region is a common feature of disc degeneration. Our previous work indicated that TNF-α promoted NP cell senescence. Although the intervertebral disc has been reported to be an estrogen-sensitive tissue, it is unclear whether estrogen can inhibit premature senescence of NP cells.
To investigate whether 17beta-estradiol (E) can attenuate TNF-α-induced premature senescence of NP cells and the potential mechanism behind this regulatory process.
Isolated NP cells and intact intervertebral discs from healthy rats were cultured with or without TNF-α, E or their combination. The pan estrogen receptor (ER) antagonist ICI 182780 was used to investigate the role of ER. Direct and indirect indicators including cell proliferation, SA-β-Gal activity, telomerase activity, cell cycle, and the expression of matrix macromolecules (aggrecan and collagen II) and senescence markers (p16 and p53) were used to evaluate the premature senescence of NP cells. Additionally, intracellular reactive oxygen species (ROS) and NF-κB/p65 activity were also detected in the NP cell cultures.
In the NP cell cultures, E significantly increased cell proliferation potency, telomerase activity and the expression of matrix macromolecules but attenuated SA-β-Gal activity, senescence marker (p53 and p16) expression and G1 cycle arrest in TNF-α-treated NP cells. Furthermore, E inhibited ROS generation and phospho-NF-κB/p65 expression in the TNF-α-treated NP cells. However, the ER antagonist ICI 182780 abolished the effects of E on TNF-α-treated NP cells. In the disc organ cultures, E also significantly increased matrix synthesis, whereas it decreased senescence marker (p53 and p16) expression, which could be abolished by the ER antagonist ICI 182780.
The interaction between E and ER can attenuate TNF-α-induced premature senescence of rat NP cells through interfering with the ROS/NF-κB pathway.
髓核（NP）区域细胞加速衰老为椎间盘退变的常见特征。我们之前的研究表明肿瘤坏死因子-α（TNF-α）可促进NP细胞衰老。尽管椎间盘被报道为雌激素敏感组织，但雌激素是否能抑制NP细胞过早衰老尚不清楚。
探讨17β-雌二醇（E）是否能减轻TNF-α诱导的NP细胞过早衰老及其调控过程背后的潜在机制。
将分离出的NP细胞和来自健康大鼠的完整椎间盘分别在有或无TNF-α、E或二者组合的条件下培养。使用泛雌激素受体（ER）拮抗剂ICI 18278来研究ER的作用。使用包括细胞增殖、衰老相关β-半乳糖苷酶（SA-β-Gal）活性、端粒酶活性、细胞周期以及基质大分子（聚集蛋白聚糖和Ⅱ型胶原）和衰老标志物（p16和p53）表达等直接和间接指标来评估NP细胞的过早衰老。此外，还检测了NP细胞培养物中的细胞内活性氧（ROS）和核因子κB（NF-κB）/p65活性。
在NP细胞培养物中，E显著提高细胞增殖能力、端粒酶活性和基质大分子的表达，但减弱了TNF-α处理的NP细胞中的SA-β-Gal活性、衰老标志物（p53和p16）表达以及G1期阻滞。此外，E抑制了TNF-α处理的NP细胞中的ROS生成和磷酸化NF-κB/p65表达。然而，ER拮抗剂ICI 182780消除了E对TNF-α处理的NP细胞的作用。在椎间盘器官培养物中，E也显著增加了基质合成，而降低了衰老标志物（p53和p16）表达，这可被ER拮抗剂ICI 182780消除。
E与ER之间的相互作用可通过干扰ROS/NF-κB途径减轻TNF-α诱导的大鼠NP细胞过早衰老。
