Turan Aasma, Gill Ravinder, Dudeja Pradeep K, Mohan Harsh, Mahmood Akhtar
Department of Biochemistry, Panjab University, Chandigarh, India.
Dig Dis Sci. 2009 Jun;54(6):1229-36. doi: 10.1007/s10620-008-0490-9. Epub 2008 Nov 7.
Immature epithelial cells generated in the crypt base undergo differentiation while progressing to the villus tip, where the cells upon apoptosis are detached from the underlying muscular tissue. We previously reported that lipid peroxidation might be involved in the turnover of enterocytes across the crypt-villus axis in rat intestine (Dig Dis Sci 52:1840-1844, 2007). To examine whether long-term feeding of fat with different fatty-acid composition influences this process, in the present study we investigated the effect of feeding fish oil (n - 3) and corn oil (n - 6) polyunsaturated fatty acids on lipid per-oxidation and anti-oxidant systems in different epithelial cell fractions isolated in rat intestine. Feeding fish oil or corn oil markedly enhanced lipid per-oxidation levels of enterocytes throughout villus height compared with control, but there was no difference in the distribution profile of pro- and anti-oxidant enzyme systems and lipid per-oxidation across the crypt-villus axis under these conditions. Analysis of lipid peroxidation levels in different cell fractions revealed that the thiobarbituric acid reactive substance were 9- to 11-fold higher at the villus tip compared with at the crypt base. The activities of glutathione reductase and glutathione-S-transferase were 2- to 5-fold higher in villus tip compared to the crypt region. However, the activities of superoxide dismutase and catalase were 6- to 8-fold high at the crypt base compared with at villus tip cells. Immunocytolocalization of superoxide dismutase showed high staining in crypt base compared with that in villus, tip cells. These findings further suggest that generation of reactive oxygen species in enterocytes across the crypt-villus axis may be involved in turnover of enterocytes across the crypt-villus unit in rat intestine.
在隐窝底部产生的未成熟上皮细胞在向绒毛顶端迁移的过程中发生分化，在绒毛顶端，细胞凋亡后从下方的肌肉组织脱离。我们之前报道过，脂质过氧化可能参与大鼠肠道中肠上皮细胞沿隐窝 - 绒毛轴的更新（《消化系统疾病科学》52:1840 - 1844，2007）。为了研究长期喂食不同脂肪酸组成的脂肪是否会影响这一过程，在本研究中，我们调查了喂食鱼油（n - 3）和玉米油（n - 6）多不饱和脂肪酸对从大鼠肠道分离的不同上皮细胞组分中脂质过氧化和抗氧化系统的影响。与对照组相比，喂食鱼油或玉米油显著提高了整个绒毛高度的肠上皮细胞的脂质过氧化水平，但在这些条件下，抗氧化酶系统和脂质过氧化在隐窝 - 绒毛轴上的分布情况没有差异。对不同细胞组分中脂质过氧化水平的分析表明，与隐窝底部相比，绒毛顶端的硫代巴比妥酸反应性物质高9至11倍。与隐窝区域相比，绒毛顶端的谷胱甘肽还原酶和谷胱甘肽 - S - 转移酶的活性高2至5倍。然而，与绒毛顶端细胞相比，隐窝底部的超氧化物歧化酶和过氧化氢酶的活性高6至8倍。超氧化物歧化酶的免疫细胞定位显示，与绒毛顶端细胞相比，隐窝底部的染色更强。这些发现进一步表明，大鼠肠道中肠上皮细胞沿隐窝 - 绒毛轴产生的活性氧可能参与了肠上皮细胞沿隐窝 - 绒毛单元的更新。
