Department of Biochemistry and Molecular Biology, The Key Laboratory of Neurobiology and Vascular Biology, China Administration of Education, Hebei Medical University, No, 361 Zhongshan East Road, Shijiazhuang, 050017, China.
Cardiovasc Diabetol. 2012 Oct 11;11:126. doi: 10.1186/1475-2840-11-126.
There is overwhelming evidence that dietary supplementation with n-3 polyunsaturated fatty acids (PUFAs), mainly EPA (C20:5n-3) and DHA (C22:6n-3), has cardiovascular protective effects on patients with type 2 diabetes mellitus (T2DM) but not on healthy people. Because the T2DM heart increases fatty acid oxidation (FAO) to compensate for the diminished utilization of glucose, we hypothesize that T2DM hearts consume more n-3 PUFAs and, therefore, need more n-3 PUFAs. In the present study, we investigated the changes in cardiac n-3 PUFAs and peroxisomal beta-oxidation, which are responsible for the degradation of PUFAs in a high-fat diet (HFD) and low-dose streptozotocin- (STZ) induced type 2 diabetic rat model.
The capillary gas chromatography results showed that all the n-3 (or omega-3) PUFAs, especially DHA (50%) and EPA (100%), were significantly decreased, and the n-6/n-3 ratio (~115%) was significantly increased in the hearts of diabetic rats. The activity of peroxisomal beta-oxidation, which is crucial to very-long-chain and unsaturated FA metabolism (including DHA), was significantly elevated in DM hearts. Additionally, the real-time PCR results showed that the mRNA expression of most peroxisomal beta-oxidation key enzymes were up-regulated in T2DM rat hearts, which might contribute to the reduction of n-3 (or omega-3) PUFAs.
In conclusion, our results indicate that T2DM hearts consume more n-3 PUFAs, especially DHA and EPA, due to exaggerated peroxisomal beta-oxidation.
有大量证据表明，膳食补充 n-3 多不饱和脂肪酸（PUFAs），主要是 EPA（C20:5n-3）和 DHA（C22:6n-3），对 2 型糖尿病（T2DM）患者具有心血管保护作用，但对健康人没有作用。由于 T2DM 心脏增加脂肪酸氧化（FAO）以补偿葡萄糖利用的减少，我们假设 T2DM 心脏消耗更多的 n-3 PUFAs，因此需要更多的 n-3 PUFAs。在本研究中，我们研究了心脏 n-3 PUFAs 和过氧化物酶体 β-氧化的变化，这些变化负责在高脂肪饮食（HFD）和低剂量链脲佐菌素（STZ）诱导的 2 型糖尿病大鼠模型中降解 PUFAs。
毛细管气相色谱结果表明，所有 n-3（或 ω-3）PUFAs，特别是 DHA（50%）和 EPA（100%），在糖尿病大鼠心脏中显著降低，而 n-6/n-3 比值（~115%）显著升高。过氧化物酶体 β-氧化的活性，对超长链和不饱和 FA 代谢（包括 DHA）至关重要，在 DM 心脏中显著升高。此外，实时 PCR 结果表明，T2DM 大鼠心脏中大多数过氧化物酶体 β-氧化关键酶的 mRNA 表达上调，这可能导致 n-3（或 ω-3）PUFAs 的减少。
总之，我们的结果表明，由于过氧化物酶体 β-氧化的夸张，T2DM 心脏消耗更多的 n-3 PUFAs，特别是 DHA 和 EPA。
