| 摘要: | 忙碌生活中，方便快速的飲食成為人們考量的選擇，然而油炸食品充斥其中，研究指出炸油會降低體內維生素 E 含量，並顯著惡化 DSS (dextran sulfate sodium) 誘發結腸炎病程發展，有研究顯示辣木具有抗氧化功能。因此本研究目的在於探討補充維生素 E 與辣木葉對炸油惡化小鼠結腸炎病程之影響。
採用 7 週齡 C57BL/6 品系雌鼠 40 隻，體重 19.9 ± 0.7 克，隨機分成四組，包括控制組 (15% 新鮮油, C)、炸油組 (15% 炸油, O)、炸油加維生素 E 組 (15% 炸油 + 維生素 E, OE)、炸油加辣木組 (15% 炸油 + 6% moringa leaves, OM)，實驗全程供應 AIN-93G 基礎飼料，令其自由攝取 (ad libitum)。飼養 6 週後於飲用水中添加 2% DSS (w/v)，誘發腸道發炎，並計算疾病活動指數 (disease activity index, DAI)，連續 5 天後換成去離子水 2 天後犧牲，取血液、肝臟與大腸，分析脂質過氧化指標 TBARS、抗氧化分子、酵素活性與 mRNA 基因表現。
結果顯示 O、OE、OM 組的 DAI 指數從第 4 天開始顯著高於 C 組，表示餵食炸油有惡化 DSS 誘發結腸炎，其中的第四天 DAI 指數 OM 組顯著低於 O 組；炸油餵食小鼠的血清發炎指標 Haptoglobin (Hp) 與 TNF-α 顯著升高。OE 組的 α-生育醇與 α-生育醇/Triglyceride (TG) 比例均顯著高於 C組。在大腸方面，OE 組的 TBARS 顯著低於 O 組；O 組的GR、GPx、GST 活性，CAT、GST mRNA均顯著高於 C 組，推測小鼠提高大腸之 GPx、GST 活性用以代謝脂質過氧化物、增加解毒作用，以提高結腸的保護力。炸油餵食有降低大腸 Nrf2 mRNA 含量的趨勢，O 組的 COX2 mRNA 含量顯著高於 C 組；OE 組的 NF-κB 和 COX2 mRNA 含量顯著低於 O 組；OM 組的 COX2、iNOS 和 NOX1 mRNA 含量顯著低於 O 組，可得知補充維生素 E 與辣木葉有助於降低 NF-κB 下游發炎基因之表現。肝臟方面，炸油餵食顯著升高 TBARS，但 OM 組顯著低於 O 組；餵食炸油顯著增加 CAT 抗氧化酵素活性，O 組中可看到 SOD 活性顯著下降、CAT活性顯著增加。SOD mRNA 受炸油影響有增加的趨勢，添加辣木葉會顯著增加 SOD及 PPARγ mRNA 表現。在肝臟與結腸，O 組的 α-生育醇顯著低於 C 組，而 OE、OM 組均顯著高於 O 組，因此添加維生素E與辣木葉可顯著提升組織中維生素E含量。結論：炸油可能藉由增加氧化損傷與發炎反應惡化腸炎病程，補充10倍的維生素E能有效提升體內維生素E含量，並減少脂質過氧化物之生成，但對炸油惡化腸炎病程進展無顯著緩和效應，推測維生素 E 營養狀況不良可能不是炸油惡化病程的主因；而補充辣木葉能提升大腸和肝臟中維生素E含量，並減少脂質過氧化物之生成，增加大腸抗氧化與外來物代謝作用，有緩和腸炎病程現象，推測可能與降低促發炎轉錄因子 NF-κB 活化有關。
Oxidized frying oil (OFO) diet has been reported to induce an increase in lipid per-oxidation and a reduction in vitamin E status in animal tissues. Our preliminary results showed that OFO-fed mice were more susceptible to DSS (dextran sulfate sodium)-induced colitis. We chose vitamin E and moringa leaves to test the ameliorative effects about deleterious process induced by OFO. The purpose of this study was to investigate the effects of vitamin E and moringa leaves supplementations on the symptoms of DSS-induced colitis in OFO-fed mice.
Forty of female 7-weeks-old C57BL/6 mice (19.9 ± 0.7 g) were randomly divided into 4 groups, including a control group (15% fresh soybean oil, C), O group (15% OFO), OE group (15% OFO + vitamin E) and OM group (15% OFO + 6% Moringa leaves). After 6 wks-feeding period, all mice were induced acute colitis by adding 2% DSS (w/v) in their drinking water for 5 days. On day 7 after receiving 2% DSS, all mice were killed, then collected blood, colon and liver. Clinical symptoms and the disease activity index (DAI) were recorded daily during acute colitis.
In OFO-fed mice, the DAI were significantly increased from day 4. The serum haptoglobin (Hp) and tumor necrosis factor alpha (TNF-α) were significantly increased in OFO-fed mice. Serum α-tocopherol and α-tocopherol/TG were significantly increased in the OE group than in the C group. In the results of colon, TBARS in OE group were significantly lower than O group; the activities of GR, GPx, GST and the mRNA abundances of CAT, GST in O group were significantly higher than the C group. The NF-κB and COX2 mRNA expression were significantly lower in the OE group than in the O group. The mRNA abundances of COX2, iNOS and NOX1 were significantly lower in the OM group than in the O group. Both of vitamin E and moringa leaves supplementations tended to reduce the NF-κB and inflammatory associated genes expression. In the results of liver, TBARS were significantly increased in OFO-fed mice. CAT activities were significantly increased; SOD activities were significantly lower in OFO-fed mice. Supplementation of moringa leaves had an significant increase in the mRNA abundances of SOD and PPARγ. In both of liver and colon, α-tocopherol were significantly lower in the O group than in the C group, but OE and OM groups had an significant increase in α-tocopherol contents compared with O group.
In conclusion, OFO-fed mice may tend to increase oxidative stress and inflammatory status with deterioration the progression of acute colitis. We suggested that poor vitamin E status is not the main reason to worse DSS-induced colitis in OFO-fed mice. Vitamin E and moringa leaves supplementations not only significantly increased the vitamin E content but also significantly reduced the TBARS contents. However, moringa leaves had DAI-lowered effect. We speculated that moringa leaves may have specifically effects on the balance of NF-κB and other transcription factors. |
