Neuroanesthesia Research Laboratory, Department of Anesthesiology, University of Illinois at Chicago, 835 S. Wolcott Ave., Rm. E-714C, Chicago, IL 60612, USA.
Am J Physiol Heart Circ Physiol. 2009 Dec;297(6):H2059-67. doi: 10.1152/ajpheart.00445.2009. Epub 2009 Oct 9.
In this study, we tested the hypothesis that the documented transformation of 17beta-estradiol (E2) from a counterinflammatory hormone in nondiabetic (ND) rats to a proinflammatory agent in rats with diabetes mellitus (DM) is due to an enhanced contribution from the receptor for advanced glycation end products (RAGE). Rhodamine 6G-labeled leukocytes were observed through a closed cranial window in rats. In vivo pial venular leukocyte adherence and infiltration were measured over 10 h reperfusion after transient forebrain ischemia in DM (streptozotocin) versus ND intact, ovariectomized (OVX), and E2-replaced (for 7-10 days) OVX (OVE) females. The role of RAGE was examined in two ways: 1) RAGE knockdown via topical application of RAGE antisense versus missense oligodeoxynucleotide or 2) intracerebroventricular injection of the RAGE decoy inhibitor, soluble RAGE. Among diabetic rats, the lowest levels of cortical RAGE mRNA and immunoreactivity of the RAGE ligand, AGE, were seen in OVX females, with significantly higher levels exhibited in intact and OVE females. However, results from the analysis of cortical RAGE protein only partially tracked those findings. When comparing ND to DM rats, cortical AGE immunoreactivity was significantly lower in OVE and intact females but similar in OVX rats. In DM rats, the level of postischemic leukocyte adhesion and infiltration (highest to lowest) was OVE>intact>>untreated OVX. In NDs, adhesion was highest in the untreated OVX group. Leukocyte extravasation was observed at >6 h postischemia but only in diabetic OVE and intact females and in ND OVX (untreated) rats. Pretreatment with RAGE antisense-oligodeoxynucleotide or soluble RAGE attenuated postischemic leukocyte adhesion and prevented infiltration but only in the diabetic OVE and intact groups. These results indicate that the exacerbation of postischemic leukocyte adhesion by chronic E2 replacement therapy in diabetic OVX females involves a RAGE-related mechanism. Targeting RAGE may restore the neuroprotective effect of E2 replacement therapy in diabetic females.
在这项研究中，我们检验了这样一个假设，即 17β-雌二醇（E2）在非糖尿病（ND）大鼠中从抗炎激素转变为糖尿病（DM）大鼠中的促炎物质，是由于晚期糖基化终产物（RAGE）受体的贡献增强所致。通过大鼠闭合颅窗观察罗丹明 6G 标记的白细胞。在 DM（链脲佐菌素）与 ND 完整、卵巢切除（OVX）和 E2 替代（7-10 天）OVX（OVE）雌性大鼠短暂性前脑缺血后 10 小时再灌注期间，测量脑软膜小静脉白细胞黏附和浸润。通过局部应用 RAGE 反义寡核苷酸或错义寡核苷酸或脑室内注射 RAGE 诱饵抑制剂可溶性 RAGE，研究了 RAGE 的作用。在糖尿病大鼠中，OVX 雌性大鼠皮质 RAGE mRNA 水平和 RAGE 配体 AGE 的免疫反应性最低，完整和 OVE 雌性大鼠的水平明显升高。然而，皮质 RAGE 蛋白分析的结果仅部分与这些发现相符。当比较 ND 与 DM 大鼠时，OVE 和完整雌性大鼠皮质 AGE 免疫反应性显著降低，但 OVX 大鼠相似。在 DM 大鼠中，缺血后白细胞黏附和浸润的水平（从高到低）为 OVE>完整>未治疗的 OVX。在 ND 中，未治疗的 OVX 组的黏附性最高。缺血后 6 小时以上观察到白细胞外渗，但仅在糖尿病 OVE 和完整雌性大鼠以及 ND OVX（未治疗）大鼠中观察到。用 RAGE 反义寡核苷酸或可溶性 RAGE 预处理可减轻缺血后白细胞黏附和浸润，但仅在糖尿病 OVE 和完整组中。这些结果表明，慢性 E2 替代疗法在糖尿病 OVX 雌性大鼠中加剧缺血后白细胞黏附作用涉及 RAGE 相关机制。靶向 RAGE 可能恢复糖尿病女性 E2 替代治疗的神经保护作用。
