| 摘要: | 當體內藥物代謝酵素受到食物成分的調控時，可能會造成藥物代謝受阻或促進，因而產生後續的藥物不良反應。Acetaminophen (N-acetyl-p-aminophenol; APAP)為常見的解熱鎮痛藥物，當服用過量時，可能會增加APAP代謝成毒性化學物質(N-acetyl-p-benzoquinoneimine；NAPQI)並增加肝毒性的風險。幾丁寡醣(Chitosan oligosaccharides; COS)為幾丁聚醣水解後所產生的低分子量胺醣類，具有抗氧化、保肝、抗腫瘤、抗菌及免疫刺激等作用。研究證據顯示部分幾丁寡醣能被吸收，且其保肝作用可能與COS具有抗氧化活性有關。本研究將探討餵食大鼠幾丁寡醣對乙醯胺酚(acetaminophen)代謝的影響。實驗將分成三部分，實驗一: 探討餵食COS五週後對大鼠肝臟及腎臟中藥物代謝酵素及氧化壓力之影響，將雄性Spraque-Dawley (SD)大鼠分成三組，分別為控制組、1% COS組和3% COS組飼養五週後犧牲。結果顯示: 大鼠餵食3 % COS會顯著降低肝臟CYP2C、 3A及4A之酵素活性及蛋白表現量，並輕微增加腎臟CYP2C及1A2酵素活性，；在肝臟抗氧化系統方面，1% COS組會增加Glutathione (GSH)含量與Glutathione S-transferase及NAD(P)H:quinine oxidoreductase-1 (NQO1)酵素活性，另外， 1% COS會增加腎臟中UDP-glucurosyltransferases (UGT)、GST 及NQO1酵素活性透過以上結果得知，COS可降低肝中CYP2C, 3A和4A酵素活性及蛋白表現量，此外也增加肝中GSH含量及GST、NQO1酵素活性，但不呈劑量上關係，而COS對腎臟藥物代謝酵素的影響較小。實驗二: 探討餵食大鼠COS五週後對肝臟中APAP代謝及氧化壓力的影響，將雄性SD大鼠分成五組，分別為控制組、APAP組、APAP + silymarin組、APAP + 1% COS組和APAP + 3% COS組，大鼠飼養五週後，隔夜禁食12 hr，再給予APAP (600 mg/kg,i.p)，並收集第0.5,1,2,4,6和12小時血液，隨後犧牲取其肝臟跟血液。結果顯示:給予APAP有增加alanine aminotransferase (ALT)活性趨勢(p<0.1)並顯著降低肝中GSH含量及GSH/GSSG；給予COS有下降血漿ALT活性的趨勢(p<0.1)，給予3% COS也有顯著降低APAP-Glutathione(APAP-GSH)含量並有降低肝中APAP含量的趨勢(p<0.1)，同時3% COS處理顯著減少了total CYP及cytochrome b5含量，也降低了CYP3A及CYP2E1活性，但是增加了GST酵素活性；在細胞膜轉運蛋白方面，COS可抑制肝中multidurg resistance-associated protein 2 (Mrp2)蛋白質表現量，但是Mrp3蛋白表現量則不受影響。透過以上結果得知，餵食COS可透過降低肝中Mrp2蛋白表現量及CYP2E1和CYP3A酵素活性，進而減少肝中APAP-GSH的含量。實驗三: 探討大鼠口服單一劑量幾丁寡醣對APAP (600 mg/kg, i.p)代謝及毒性的影響，將雄性SD大鼠分成三組，分別為控制組、APAP組和APAP + COS組，大鼠隔夜禁食12小時後，在給予APAP前30分鐘先給予大鼠COS (2 g/kg, p.o)或去離子水，並收集第0.5,1,2,4,6,12和24小時血液，隨後犧牲取其肝臟跟血液。結果顯示: 相較單獨給予APAP組，COS會進一步增加APAP處理後第2及第24小時血漿中ALT活性，COS也會顯著增加APAP-GSH (AUC0-24h)濃度；在藥物代謝酵素和膜轉運蛋白上，發現給予APAP 2小時後，COS會降低肝中Mrp2及Mrp3蛋白質表現量並增加肝中APAP含量，但在APAP給予後24小時，COS並不影響Mrp2及Mrp3表現量；另外相較APAP組，在第24小時，COS也會增加肝中GSSG含量、TBARS含量及HO-1蛋白表現量並降低GSH/GSSG比值(p<0.05)。透過以上結果得知，COS會增加肝中APAP經由CYP代謝生NAPQI及產生較大之氧化壓力，因而更增加APAP所引起的肝毒性。綜合以上三個實驗結果顯示: COS對APAP的代謝及毒性扮演重要的調節角色，尤其當APAP與COS共服必須謹慎。
Metabolic food-drug interactions occur when the consumption of a particular food modulates the activity of a drug-metabolizing enzyme system, resulting in an alteration of the pharmacokinetics of drugs metabolized by the system. Acetaminophen (N-acetyl-p-aminophenol；APAP) is a widely used analgesic and antipyretic drug. However, when excessive doses of APAP are ingested, APAP can convert into reactive electrophile N-acetyl-p-benzoquinoneimine (NAPQI), which causes severe liver injury that can be fatal. Chitosan oligosaccharides , which are oligosaccharides made up of β-1,4-linked D-glucosamine residues. Recent advances have insighted into the health benefits of COS including antioxidant, hepatoprotective, and antitumor properties. To investigate the effect of COS on the metabolism of acetaminophen in rats, three experiments were conducted. Experiment Ⅰ: To investigate the effect of COS on drug-metabolizing enzymes (DME) and oxidative stress in rat liver and kidneys, male Spraque-Dawley (SD) were fed a diet containing 1 or 3% COS for 5 weeks. Significant decreases in microsomal CYP3A-catalyzed testosterone 6β-hydroxylation, CYP2C-catalyzed diclofenac 4-hydroxylation, and CYP4A-catalyzed lauric acid 12-hydroxylation in the liver of rats fed the COS diet. Increased glutathione (GSH) content and glutathione S-transferase 、NADPH：quinone oxidoreductase-1 (NQO1) activity in liver were noted only in 1% COS group. Results from this study indicate that COS may reduce enzyme activities and protein expressions of CYP2C, 3A, and 4A in rat liver. The increase of GSH content, and GST and NQO1activities by COS in the liver is not a dose-dependent phenomenon. COS had little or no effect on DME in rat kidneys. Experiments Ⅱ: The aim of the present study was to investigate the effect of COS administration (1 and 3% COS diet for 5 weeks) on APAP metabolism and oxidative stress in liver. Male SD rats were divided into five groups: 1. control group; 2. APAP group; 3. APAP + silymarin; 4. APAP + 1% COS group; 5. APAP + 3% COS group. After 5 weeks of COS feeding, APAP (600 mg/kg) was administered through intraperitoneal injection and blood was collected at 0.5, 1, 2, 4, 6 and 12 hrs. Rats were sacrificed at 12 hrs and livers were collected. Results show that increased alanine aminotransaminase (ALT) level and decreased GSH concent and GSH/GSSG ratio in liver were observed after APAP treatment. COS treatment tended to reduce (p<0.1) plasma ALT concentration. However, rats treated 3% COS reduced APAP-glutathione (APAP-GSH) content in liver. The hepatic APAP content also tended to reduced (p<0.1) in liver by 3% COS treatment. Moreover, the hepatic total p450, cytochrome b5 content and CYP 2E1 and CYP3A activities were reduced by 3% COS treatment. An increase in GST activity was noted in 3% COS group. Rat treated with COS reduced multidrug resistnace-associated protein 2 (Mrp2) protein without changing Mrp3 levels in the liver. Results from this study indicate that COS feeding may reduce APAP-glutathione formation in liver through the depletion of Mrp2 preotein expression and lower CYP2E1 and CYP 3A activities. Experiments Ⅲ: The effect of chitosan oligosaccharides on metabolism and toxicity of acetaminophen (APAP 600 mg/kg, i.p) were examined in male SD rats. Pretreated with single dose of COS (2 g/kg, p.o) increased the APAP hepatotoxicity as indicated by increasing plasma ALT after 2 and 24 hours of APAP treatment. Quantification of major APAP metabolites in plasma (area under the curve; AUC) showed that COS was significantly increased AUC0-24h of APAP-glutathione. At 2h after APAP treatment, COS decreased the Mrp2 and Mrp3 protein levels and increased APAP content in the liver. However, Mrp2 and Mrp3 levels were not changed at 24 h after APAP treatment. Moreover, rat pretreated with COS increased the GSSG, thiobarbituric acid-reactive substance (TBARS) and heme oxygenase-1 (HO-1) protein levels and reduced GSH/GSSG ratio in the liver at 24 h after APAP treatment. These results indicate that COS may enhance hepatotoxicity of APAP in rats by increasing CYP-mediated APAP metabolism and oxidative stress in liver. Results from our studies indicate that COS may play an important role in regulating the metabolism and toxicity of APAP. Caution should be paid when APAP is taken with COS. |
