Hara Y, Fujino M, Adachi K, Li X-K
Laboratory of Transplantation Immunology and National Research Institute for Child Health and Development, Tokyo, Japan.
Transplant Proc. 2006 Oct;38(8):2722-5. doi: 10.1016/j.transproceed.2006.08.010.
The survival of transplanted tissue is affected by the detrimental consequences of hypoxia followed by reoxygenation. The majority of transplanted cells undergo apoptosis due to hypoxia and reoxygenation (H/R) injury, but protection from H/R has been less examined. In this study, we examined whether epigallocatechin gallate (EGCG) protected rat islets from H/R injury. Rat islets, freshly prepared from F344 rat strain by collagenase digestion and density centrifugation, were seeded in triplicate at concentrations of 100 per well in 24-well plates for culture under normoxia. The cells were then exposed to hypoxia for 14 hours with or without EGCG, after which they were reoxygenated for 72 hours in a humidified oxygenated CO(2) incubator at 37 degrees C. Apoptosis, lactate dehydrogenase (LDH), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were evaluated according to the manufacturer's instructions. The H/R induced apoptosis in the islets that was reduced in dose-dependent manner by EGCG treatment. The viability of islets exposed to H/R was assessed by LDH release. H/R reduced viability compared with the controls, while the viability of the islets improved upon EGCG treatment. The secretion of insulin was also decreased by H/R, as well as the dose dependent EGCG protective ability on insulin secretion. The content of 8-OHdG in islets from H/R was also reduced by EGCG. Our results indicated that apoptosis and the decline in insulin secretion by H/R were inhibited by EGCG treatment. EGCG may be considered useful for protection of islets from oxidative injury associated with the transplantation procedure.
移植组织的存活受到缺氧继以再给氧的有害后果的影响。大多数移植细胞由于缺氧和再给氧（H/R）损伤而发生凋亡，但针对H/R的保护作用研究较少。在本研究中，我们检测了表没食子儿茶素没食子酸酯（EGCG）是否能保护大鼠胰岛免受H/R损伤。通过胶原酶消化和密度离心从F344大鼠品系新鲜制备的大鼠胰岛，以每孔100个的浓度一式三份接种于24孔板中，在常氧条件下培养。然后将细胞在有或无EGCG的情况下暴露于缺氧环境14小时，之后在37℃的加湿充氧CO₂培养箱中再给氧72小时。根据制造商的说明评估凋亡、乳酸脱氢酶（LDH）和8-羟基-2'-脱氧鸟苷（8-OHdG）。H/R诱导胰岛发生凋亡，而EGCG处理以剂量依赖的方式减少了凋亡。通过LDH释放评估暴露于H/R的胰岛的活力。与对照组相比，H/R降低了活力，而EGCG处理后胰岛的活力有所改善。H/R还降低了胰岛素的分泌，以及EGCG对胰岛素分泌的剂量依赖性保护能力。EGCG也降低了H/R组胰岛中8-OHdG的含量。我们的结果表明，EGCG处理可抑制H/R诱导的凋亡和胰岛素分泌下降。EGCG可能被认为有助于保护胰岛免受与移植过程相关的氧化损伤。
