烹飪油煙成分誘導腎臟細胞衰老損傷及蓮藕保護效應之體內外研究

反式‑2,4‑癸二烯醛(trans, trans‑2,4‑decadienal, tt‑DDE)是烹飪油煙中含量最高的毒性醛類，也是室內空氣污染的主要來源。長期暴露tt-DDE會造成人類支氣管上皮細胞異常增生和刺激其氧化壓力(oxidative stress)和發炎(inflammation)反應，以及引發小鼠高血壓和內皮功能障礙；然而tt-DDE致慢性腎病(chronic kidney disease, CKD)的影響仍是未知，氧化壓力在腎臟老化(senescence)和損傷中至關重要，另研究指出抗氧化物具潛力開發為CKD化學預防物質，已知蓮藕萃取物(lotus root extracts, LRE)富含兒茶素和原兒茶酸(protocatechuic acid, PCA)等抗氧化成份，LRE護腎功效仍有待釐清。本文於體外實驗中，以繼代數區分年輕與衰老大鼠腎小管上皮細胞NRK-52E，並以tt-DDE 暴露24小時，探討tt-DDE對腎小管細胞老化與損傷之影響。結果顯示tt-DDE會增加年輕與衰老NRK-52E細胞中衰老相關 β-半乳糖苷酶(senescence-associated β-galactosidase, SA-β-gal)陽性細胞比例，且此作用在衰老細胞中更為明顯。經tt-DDE處理後，衰老細胞中細胞週期蛋白依賴性激酶抑制因子p21、p16、p15及p53表現上升，並抑制抗衰老蛋白SIRT1表現，顯示tt-DDE會加速腎小管細胞老化並影響細胞增生能力，且相較於年輕細胞，衰老細胞對tt-DDE所誘發之細胞毒性更加敏感。進一步透過標的預測分析發現，視黃酸相關孤兒受體(retinoic acid-related orphan receptors, RORs)可能參與tt-DDE誘發腎臟老化與發炎反應之調控，其中抗發炎因子RORα會受到tt-DDE抑制。而LRE處理後可改善衰老NRK-52E細胞之細胞型態與存活率，降低衰老相關分泌表型(senescence-associated secretory phenotype, SASP)含量，並使細胞週期分布趨於正常。此外，LRE亦可降低細胞凋亡比例，並伴隨caspase 3及p53表現下降，顯示LRE可能透過減少細胞老化、發炎與凋亡反應，發揮腎小管細胞保護作用。在體內實驗中，利用年輕與老年鼠暴露於tt-DDE，以誘發腎臟損傷與老化，並評估LRE與PCA給予對tt-DDE所致腎臟病變之保護效果。結果顯示LRE與PCA可顯著減緩tt-DDE誘發之CKD發展，其可能機制與抑制tt-DDE所造成SASP產生、細胞老化及凋亡有關。分子對接分析亦支持PCA可能與關鍵抗發炎標的RORα產生交互作用，進一步指出PCA可能為LRE發揮抗發炎與護腎作用之重要活性成分。綜合上述，tt-DDE會加速腎小管細胞衰老與凋亡，並惡化腎功能；而LRE與PCA則具有抗發炎、抑制細胞老化與凋亡等多重護腎效果。本研究提出LRE及PCA具有作為預防tt-DDE致腎臟老化與CKD之天然介入策略的潛力。

Trans, trans-2,4-decadienal (tt-DDE) is the most abundant toxic aldehyde in cooking oil fumes (COFs), a major source of indoor air pollution. Long-term exposure to tt-DDE can promote abnormal proliferation of human bronchial epithelial cells and stimulate oxidative stress and inflammation, as well as lead to hypertension and endothelial dysfunction in mice. However, it is unknown whether tt-DDE exposure has been associated with chronic kidney disease (CKD), focusing on renal senescence closely related to inflammation and oxidative stress. It is known that lotus root extracts (LRE), rich in polyphenols such as catechin and protocatechuic acid (PCA), has attracted much attention due to the strong antioxidant capacities, and the renal-protective efficacy of LRE remains to be clarified. In vitro, rat renal tubular epithelial NRK-52E cells were categorized as young or senescent by passage and exposed to tt-DDE for 24 h. In both young and senescent NRK-52E cells, tt-DDE increased senescence-associated β-galactosidase (SA-β-gal)-positive cells, with markedly stronger effects in senescent cells. Senescent cells showed increases in levels of cyclin-dependent kinase inhibitor p21, p16, p15, p53, and suppressed anti-senescence protein SIRT1 after tt-DDE, indicating tt-DDE accelerated senescence and impaired proliferation, and it’s more susceptible to tt-DDE cytotoxicity on senescent cells than young cells. Target prediction implicated retinoic acid-related orphan receptors (RORs), with reduced RORα, an anti-inflammatory factor, by tt-DDE. LRE restored morphology and survival of senescent NRK-52E cells, reduced senescence-associated secretory phenotype (SASP) secretion, and normalized cell cycle distribution. Decreased apoptosis and a coincident reduction of active-caspase 3 and p53 followed treatment with LRE. In vivo, young and aged mice exposed to tt-DDE to induce renal injury and aging were subjected. LRE and PCA supplementations significantly alleviated CKD development, which may result from inhibiting tt-DDE-induced SASPs production accompanying senescence and apoptosis in aged mice. Molecular docking supported potential interactions between PCA and key anti‑inflammatory target ROR. Overall, tt-DDE accelerates renal tubular cell aging and apoptosis and worsens renal function, whereas LRE and PCA exert multiple renoprotective effects. These findings suggest that LRE and PCA may serve as natural intervention strategies for preventing tt-DDE-related renal aging and CKD.