Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze, 90128, Palermo, Italy.
ATeN (Advanced Technologies Network) Center, Viale delle Scienze, 90128, Palermo, Italy.
Inflammopharmacology. 2020 Feb;28(1):187-199. doi: 10.1007/s10787-019-00619-z. Epub 2019 Jul 18.
Angiotensin II, the main effector of renin angiotensin system, plays an important role in the inflammatory process and most of its effects are mediated through the AT1 receptor activation. However, the knowledge about the AT2 receptor involvement in this process is still evolving. We previously found that in an experimental model of colitis, AT2 receptor activation can contribute to the impairment of the muscle contractility in vitro in the course of inflammation. Here, we investigated the potential alleviating effects of the in vivo treatment of PD123319 (1-[[4-(Dimethylamino)-3-methylphenyl]methyl]-5-(diphenylacetyl)-4,5,6,7- tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid ditrifluoroacetate), AT2 receptor antagonist, in 2,4-dinitrobenzene sulfonic acid (DNBS)-induced rat model of colitis. The effects of i.p PD123319 (0.3, 3 and 10 mg/kg) administration to rats subjected to intra-rectal DNBS instillation were investigated. The study revealed that the colon injury and the inflammatory signs were ameliorated by PD123319 when visualized by the histopathological examination. The colon shortening, myeloperoxidase activity, and colonic expression of IL-1β, IL-6 and iNOS were downregulated in a dose-dependent manner in DNBS-induced colitis rats treated with PD123319 and the anti-oxidant defense machinery was also improved. The mechanism of these beneficial effects was found in the ability of PD123319 to inhibit NF-κB activation induced by DNBS. The colonic contractility in inflamed tissues was also improved by PD123319 treatment. In conclusion, our data have demonstrated previously that undescribed proinflammatory effects for the AT2 receptors in DNBS-induced colitis in rats in which they are mediated likely by NF-κB activation and reactive oxygen species generation. Moreover, when the inflammatory process is mitigated by the AT2 receptor antagonist treatment, the smooth muscle is able to recover its functionality.
血管紧张素 II 是肾素-血管紧张素系统的主要效应物,在炎症过程中发挥重要作用,其大多数作用是通过 AT1 受体激活介导的。然而,关于 AT2 受体在这一过程中的参与,我们的了解仍在不断发展。我们之前发现,在结肠炎的实验模型中,AT2 受体的激活可能有助于炎症过程中体外肌肉收缩力的损害。在这里,我们研究了体内给予 PD123319(1-[[4-(二甲基氨基)-3-甲基苯基]甲基]-5-(二苯乙酰基)-4,5,6,7-四氢-1H-咪唑[4,5-c]吡啶-6-羧酸二三氟乙酸酯),AT2 受体拮抗剂,对 2,4-二硝基苯磺酸(DNBS)诱导的大鼠结肠炎模型的潜在缓解作用。研究了腹腔内给予 PD123319(0.3、3 和 10mg/kg)对直肠内 DNBS 灌注大鼠的影响。组织病理学检查显示,PD123319 可改善结肠损伤和炎症迹象。PD123319 以剂量依赖的方式下调 DNBS 诱导的结肠炎大鼠的结肠缩短、髓过氧化物酶活性以及结肠中白细胞介素-1β、白细胞介素-6 和诱导型一氧化氮合酶的表达,并改善抗氧化防御机制。这种有益作用的机制在于 PD123319 能够抑制 DNBS 诱导的 NF-κB 激活。PD123319 治疗还改善了炎症组织中结肠的收缩性。总之,我们的数据表明,在大鼠的 DNBS 诱导的结肠炎中,AT2 受体具有以前未描述的促炎作用,其机制可能是通过 NF-κB 激活和活性氧生成介导的。此外,当炎症过程通过 AT2 受体拮抗剂治疗得到缓解时,平滑肌能够恢复其功能。