Wang H-W, Yang C-N, Kok S-H, Hong C-Y, Shun C-T, Lai E H-H, Cheng S-J, Lin H-Y, Wu F-Y, Lin S-K
Department of Dentistry, National Taiwan University Hospital, Taipei, Taiwan.
Graduate Institute of Clinical Dentistry, School of Dentistry, College of Medicine, National Taiwan University, Taipei, Taiwan.
Int Endod J. 2025 Jan;58(1):97-110. doi: 10.1111/iej.14143. Epub 2024 Sep 10.
The influence of hypercholesterolemia on the development of apical periodontitis (AP) is inconclusive. Recent studies revealed that cholesterol metabolite 27-hydoxycholesterol (27HC) can affect cellular responses to bacterial infections and oestrogen status and raloxifene may influence its action. Herein, we aimed to examine the impact of 27HC on production of inflammatory mediators by macrophages and the regulatory function of raloxifene. The contribution of 27HC to AP development and the therapeutic effect of raloxifene were evaluated in a rat model.
Murine macrophages J774 cells were used. The expression of inducible nitric oxide synthase (iNOS) was examined by Western blot. The concentrations of C-C motif chemokine ligand (CCL) 2 and 27HC were assessed by enzyme-linked immunosorbent assay. Colorimetric assay was used to evaluate cholesterol levels. Experimental AP was induced in ovariectomized (OVX) or un-operated rats receiving high-fat/high-cholesterol diet (HFHCD) or normal diet (ND). Micro-computed tomography and immunohistochemistry were employed to evaluate disease severity and the therapeutic effect of raloxifene.
Cholesterol enhanced 27HC production in macrophages. 27HC induced iNOS and CCL2 synthesis by macrophages and estradiol suppressed the responses. In our animal model of AP, HFHCD plus OVX significantly augmented serum and lesion tissue levels of 27HC (p < .05 versus the ND group). Lesion size, infiltration of CD68 cells, and iNOS monocytes were increased in parallel with 27HC accumulation. Raloxifene inhibited pro-inflammatory effects of 27HC on macrophages and suppressed AP progression in HFHCD/OVX rats (p < .05 versus the vehicle control group).
Our results suggested that 27HC contributes to AP aggravation associated with hypercholesterolemia. Oestrogen deficiency may both enhance 27HC production and exacerbate its downstream action.
高胆固醇血症对根尖周炎（AP）发展的影响尚无定论。近期研究表明，胆固醇代谢产物27-羟基胆固醇（27HC）可影响细胞对细菌感染的反应以及雌激素状态，而雷洛昔芬可能会影响其作用。在此，我们旨在研究27HC对巨噬细胞炎症介质产生的影响以及雷洛昔芬的调节功能。在大鼠模型中评估了27HC对AP发展的作用以及雷洛昔芬的治疗效果。
使用小鼠巨噬细胞J774细胞。通过蛋白质免疫印迹法检测诱导型一氧化氮合酶（iNOS）的表达。采用酶联免疫吸附测定法评估C-C基序趋化因子配体（CCL）2和27HC的浓度。用比色法评估胆固醇水平。在接受高脂/高胆固醇饮食（HFHCD）或正常饮食（ND）的去卵巢（OVX）或未手术大鼠中诱导实验性AP。采用微型计算机断层扫描和免疫组织化学评估疾病严重程度及雷洛昔芬的治疗效果。
胆固醇可增强巨噬细胞中27HC的产生。27HC诱导巨噬细胞合成iNOS和CCL2，而雌二醇可抑制这些反应。在我们的AP动物模型中，HFHCD加OVX显著提高了血清和病变组织中27HC的水平（与ND组相比，p < 0.05）。病变大小、CD68细胞浸润和iNOS单核细胞数量随27HC积累而增加。雷洛昔芬抑制27HC对巨噬细胞的促炎作用，并抑制HFHCD/OVX大鼠的AP进展（与载体对照组相比，p < 0.05）。
我们的结果表明，27HC促成了与高胆固醇血症相关的AP加重。雌激素缺乏可能既增强27HC的产生又加剧其下游作用。
