1. Academic Validation
  2. Pioglitazone Attenuates Experimental Colitis-Associated Hyperalgesia through Improving the Intestinal Barrier Dysfunction

Pioglitazone Attenuates Experimental Colitis-Associated Hyperalgesia through Improving the Intestinal Barrier Dysfunction

  • Inflammation. 2020 Apr;43(2):568-578. doi: 10.1007/s10753-019-01138-3.
Yulin Huang 1 Chenchen Wang 1 Xinyu Tian 1 Yanting Mao 1 Bailin Hou 1 Yu'e Sun 1 Xiaoping Gu 2 Zhengliang Ma 3
Affiliations

Affiliations

  • 1 Department of Anaesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, Jiangsu province, China.
  • 2 Department of Anaesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, Jiangsu province, China. xiaopinggu@nju.edu.cn.
  • 3 Department of Anaesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, Jiangsu province, China. mazhengliang1964@nju.edu.cn.
Abstract

Impaired intestinal mucosal integrity during colitis involves the peroxisome proliferator-activated receptor-γ (PPARγ), an important anti-inflammatory factor in intestinal mucosa homoeostasis, which is a potential target in colitis. Recurrent chronic pain is a vital pathogenetic feature of colitis. Nevertheless, potential functions of PPARγ in the colitis-associated hyperalgesia remain unclear. This study aimed to investigate biological roles of pioglitazone in relieving colitis-associated pain hypersensitivity by a PPARγ tight junction protein-dependent mechanism during the course of dextran sodium sulfate (DSS)-induced intestinal inflammation. The DSS-induced colitis model was generated in C57BL/6 mice. Changes in colitis induced the injury of intestinal mucosal barrier and hyperalgesia after a 6-day treatment of pioglitazone (25 mg/kg, IP injection) were assessed through immunofluorescent, hematoxylin and eosin (H&E) staining, western blot analysis, and determination of paw withdrawal mechanical threshold. A significant reduction of paw withdrawal mechanical threshold occurred after DSS treatment. Follow-up data showed that systematic administration of PPARγ Agonist pioglitazone ameliorated the DSS-induced colitis and the development of colitis-associated hyperalgesia by repairing the intestinal mucosal barrier. The tight junction proteins ZO-1 and Claudin-5 were upregulated by PPARγ signaling, which in turn promoted the improvement of intestinal barrier function. Moreover, pioglitazone inhibited phosphorylation of ERK and NF-κB in the colon and decreased the levels of inflammatory cytokines in both colon spine tissues. Furthermore, systemically pioglitazone treatment inhibited the activation of microglia and astrocytes, as well as DSS-induced phosphorylation of NR2B subunit in spinal cord, which was correspondingly consistent with the pain behavior. Pioglitazone ameliorates DSS-induced colitis and attenuates colitis-associated mechanical hyperalgesia, with improving integrity of the intestinal mucosal barrier by directly upregulating tight junction proteins. The PPARγ-tight junction protein signaling might be a potential therapeutic target for the treatment of colitis-associated chronic pain.

Keywords

chronic pain; colitis; hyperalgesia; intestinal barrier; pioglitazone.

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