Hirano Shinji, Higashimori Akira, Nagami Yasuaki, Nadatani Yuji, Tanigawa Tetsuya, Ominami Masaki, Fukunaga Shusei, Otani Koji, Hosomi Shuhei, Tanaka Fumio, Kamata Noriko, Taira Koichi, Watanabe Toshio, Fujiwara Yasuhiro
Department of Gastroenterology, Osaka City University Graduate School of Medicine, Osaka, Japan.
Department of Premier Preventive Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan.
J Gastroenterol Hepatol. 2022 Jun;37(6):1096-1106. doi: 10.1111/jgh.15861. Epub 2022 May 1.
Esophageal injury often results in a scar, leading to refractory strictures. The NLRP3 inflammasome activates caspase-1, causing the maturation of interleukin (IL)-1β. Here, we aimed to investigate the preventive effect of pirfenidone (PFD), an antifibrotic drug, on esophageal stricture after ulcer healing and studied its mechanism by focusing on the activation of the NLRP3 inflammasome.
Esophageal ulcers were induced in rats via the local application of acetic acid in the serosa. PFD was intraperitoneally administered to the rats 3 days after ulcer induction. The effect of PFD on esophageal stricture after ulcer healing was assessed by esophagography on day 9. The protein levels of mature caspase-1 and IL-1β were assessed by western blotting.
The ulcers fully developed 3 days after induction and were almost scarred by day 9 with severe strictures. PFD promoted ulcer healing and attenuated fibrotic collagen in the submucosa by suppressing the increase in NLRP3, cleaved caspase-1, and mature IL-1β expression, improving stricture rate (PFD vs vehicle = 55% vs 81%). Exogenous IL-1β abolished the therapeutic effects of PFD on ulcer healing and stricture formation. Furthermore, NLRP3 and caspase-1 inhibitors mimicked the effects of PFD on ulcer healing and stricture formation, with suppression of the increase in cleaved caspase-1 and mature IL-1β proteins and expression of fibrosis-related molecules including transforming growth factor (TGF)-β1.
The NLRP3 inflammasome promotes esophageal stricture formation following ulcer healing, and PFD exerts potential prophylactic activity against strictures, possibly via the inhibition of the NLRP3/IL-1β/TGF-β1 axis.
食管损伤常导致瘢痕形成，进而引发难治性狭窄。NLRP3炎性小体激活半胱天冬酶-1，促使白细胞介素（IL）-1β成熟。在此，我们旨在研究抗纤维化药物吡非尼酮（PFD）对溃疡愈合后食管狭窄的预防作用，并通过聚焦NLRP3炎性小体的激活来探讨其机制。
通过在大鼠浆膜局部应用乙酸诱导食管溃疡。在溃疡诱导后3天对大鼠进行腹腔注射PFD。在第9天通过食管造影评估PFD对溃疡愈合后食管狭窄的影响。通过蛋白质印迹法评估成熟半胱天冬酶-1和IL-1β的蛋白水平。
诱导后3天溃疡完全形成，到第9天几乎形成瘢痕且伴有严重狭窄。PFD通过抑制NLRP3、裂解的半胱天冬酶-1和成熟IL-1β表达的增加，促进溃疡愈合并减轻黏膜下层的纤维化胶原，提高狭窄率（PFD组与赋形剂组分别为55%对81%）。外源性IL-1β消除了PFD对溃疡愈合和狭窄形成的治疗作用。此外，NLRP3和半胱天冬酶-1抑制剂模拟了PFD对溃疡愈合和狭窄形成的作用，抑制了裂解的半胱天冬酶-1和成熟IL-1β蛋白的增加以及包括转化生长因子（TGF）-β1在内的纤维化相关分子的表达。
NLRP3炎性小体促进溃疡愈合后食管狭窄的形成，PFD可能通过抑制NLRP3/IL-1β/TGF-β1轴对狭窄发挥潜在的预防作用。
