新綠原酸透過降低氧化壓力及發炎反應抑制糖脂毒性所誘導 db/db 小鼠產生的糖尿病腎病變

糖尿病腎病變（DN）是一種由糖尿病(DM)引起的腎臟疾病。 DN 是全球腎功能衰竭的主要原因，也是糖尿病患者死亡率的最強預測因子。目前的研究認為DM中由血醣及脂質代謝異常所導致的糖脂毒性，在 DN 的發病機制中起重要作用。新綠原酸(nCGA)是一種存在於乾果和其他植物中的植物化學物質。根據以往的研究，nCGA 可以抑制炎症並減少氧化壓力。在本研究中，我們使用了高脂飲食(HFD)餵養db/db小鼠，來模擬糖尿病患者，受到高血糖與高血脂的影響而產生DN的生理環境。並以此模式評估nCGA對糖脂毒性誘導的DN的影響。根據血清生化指標生化和組織病理學結果，nCGA 顯著降低了HFD 餵養的db/db小鼠的腎臟組織變異與纖維化物質堆積，並且nCGA降低了腎臟組織中的氧化壓力，並抑制腎臟組織中的NF-κB發炎路徑活化。另外我們也使用細胞實驗在體外研究了nCGA的分子機制。在小鼠腎絲球系膜細胞MES-13中我們使用高糖(high glucose)模擬糖尿病患者的生理環境，並使用油酸(oleic acid)以建構T2DM患者因糖脂毒性所導致DN發生的模式。根據最終結果，我們驗證了nCGA可以增加抗氧化蛋白Nrf2的表達，並且降低細胞中，由粒線體產生的氧化壓力。本研究還驗證了氧化壓力的上升，是導致NF-κB發炎路徑的過度活化的原因，而nCGA也透過了抑制 NF-κB路徑的過度活化，並在不同的細胞中，降低了炎症因子如TNF-α、MCP-1 的表達。為了更進一步探討nCGA於腎臟中的作用機轉，本研究篩選了四個具有降低氧化壓力或抑制發炎路徑潛力的miRNA，進行分子通路驗證。根據結果顯示，nCGA透過活化靶向為NF-κB之miR-30a，並抑制靶向Nrf2之miR-709，以此抑制發炎反應及氧化壓力，並改善DN。根據以上實驗結果，本研究證實了nCGA通過抑制由糖脂毒性所誘導的氧化壓力，並下調NF-κB信號通路以減少促炎細胞因子產生，減少腎小球變異與腎臟氧化壓力上升，以維持腎功能，最終改善糖尿病腎損傷。目前的結果表明，nCGA 可以通過活化miR-30a 抑制NF-κB路徑抑制發炎反應，並透過抑制miR-709活化Nrf2並降低氧化壓力，改善糖尿病腎病變。未來，我們希望對 nCGA 對 DN 的作用機制進行更多討論，以確定其生物活性。

關鍵字

nCGA ；糖尿病腎病變；糖脂毒性；發炎；氧化壓力

並列摘要

Diabetic nephropathy (DN) is a kidney disease caused by diabetes mellitus (DM). DN is the leading cause of renal failure worldwide and the strongest predictor of mortality in patients with diabetes. Current research shows that hyperglycemia and hyperlipidemia caused by DM, play an important role in the pathogenesis of DN. Neochlorogenic acid (nCGA) is a phytochemical found in dried fruits and other plants. According to previous studies, nCGA can suppress inflammation and reduce oxidative stress. In this study, we established a T2DM mouse model of DN using high-fat diet (HFD)-fed db/db mice to evaluate the effect of nCGA on DN induced by glucolipotoxicity. Based on the biochemical and histopathological results of serum biochemical markers, nCGA significantly reduced the variation and fibrosis of kidney tissue in HFD-fed db/db mice, and also reduced oxidative stress and inhibited NF-κB pathway to avoid upregulation of inflammatory in kidney tissue factors. The molecular mechanism of nCGA was studied in vitro using mouse mesangial cell line (MES-13). nCGA also suppresses the expression of inflammatory factors, TNF-α and MCP-1 in MES-13 cells by inhibited the overactivation of NF-κB pathway the same results can also be verified in human podocytes. In the other head, nCGA inhibits mitochondria-generated oxidative stress in MES-13 cells by increasing the expression of the antioxidant protein Nrrf2.We further confirmed that the increase of oxidative stress caused by glucolipotoxicity will lead to the overactivation of NF-κB inflammatory pathway. In addition, based on previous experimental results, our study screened four miRNAs with the potential to inhibit inflammation and oxidative stress, in order to further explore the mechanism of nCGA inhibiting diabetic nephropathy. According to the results, nCGA inhibits inflammatory response and oxidative stress and improves DN by activating miR-30a and inhibiting miR-709. In this study, we demonstrated that nCGA inhibits oxidative stress induced by glycolipid toxicity via micro RNAs, and downregulates the NF-κB pathway to reduce pro-inflammatory cytokine production, and to reduce glomerular variability and renal oxidative stress to maintain renal function. The present results suggest that nCGA can inhibit the NF-κB pathway by activating miR-30a, and ameliorate diabetic nephropathy by inhibiting miR-709 to activate Nrf2 and reduce oxidative stress. In the future, we hope to conduct more discussion on the mechanism of action of nCGA on DN to determine its biological activity.

並列關鍵字

nCGA ； Diabetic nephropathy ； Glucolipotoxicity ； Inflammation ； Oxidative stress

參考文獻

1. Lam, D.W., D.J.C.O.i.E. LeRoith, Diabetes, and Obesity, The worldwide diabetes epidemic. 2012. 19(2): p. 93-96.

Google Scholar

2. Sun, H., et al., IDF Diabetes Atlas: Global, regional and country-level diabetes prevalence estimates for 2021 and projections for 2045. 2022. 183: p. 109119.