Department of Medicine and Surgery, University of Insubria, 21100 Varese, Italy.
Department of Pathology, Ospedale di Circolo, ASST-Sette Laghi, 21100 Varese, Italy.
Cells. 2022 Oct 25;11(21):3370. doi: 10.3390/cells11213370.
Intestinal ischemia and reperfusion (IRI) injury induces acute and long-lasting damage to the neuromuscular compartment and dysmotility. This study aims to evaluate the pathogenetic role of hyaluronan (HA), a glycosaminoglycan component of the extracellular matrix, as a modulator of the enteric neuronal and immune function and of the colonic microbiota during in vivo IRI in the rat small intestine.
mesenteric ischemia was induced in anesthetized adult male rats for 60 min, followed by 24 h reperfusion. Injured, sham-operated and non-injured animals were treated with the HA synthesis inhibitor, 4-methylumbelliferone (4-MU 25 mg/kg). Fecal microbiota composition was evaluated by Next Generation Sequencing. Neutrophil infiltration, HA homeostasis and toll like receptor (TLR2 and TLR4) expression in the small intestine were evaluated by immunohistochemical and biomolecular approaches (qRT-PCR and Western blotting). Neuromuscular responses were studied in vitro, in the absence and presence of the selective TLR2/4 inhibitor, Sparstolonin B (SsnB 10, 30 µM).
4-MU significantly reduced IRI-induced enhancement of potentially harmful and bacteria. After IRI, HA levels, neutrophil infiltration, and TLR2 and TLR4 expression were significantly enhanced in the and were significantly reduced to baseline levels by 4-MU. In the injured, but not in the non-injured and sham-operated groups, SsnB reduced both electrical field-stimulated (EFS, 0.1-40 Hz) contractions and EFS-induced (10 Hz) non-cholinergic non-adrenergic relaxations.
enhanced HA levels after intestinal IRI favors harmful bacteria overgrowth, increases neutrophil infiltration and promotes the upregulation of bacterial target receptors, TLR2 and TLR4, in the , inducing a pro-inflammatory state. TLR2 and TLR4 activation may, however, underlay a provisional benefit on excitatory and inhibitory neuronal pathways underlying peristalsis.
肠缺血再灌注（IRI）损伤会导致肠神经系统和运动功能的急性和长期损伤以及运动障碍。本研究旨在评估透明质酸（HA）作为细胞外基质糖胺聚糖成分的致病作用，HA 是一种调节因子，可调节肠神经元和免疫功能以及肠道微生物群在大鼠小肠体内 IRI 过程中的作用。
用麻醉成年雄性大鼠肠系膜缺血 60 分钟，然后再灌注 24 小时。用透明质酸合成抑制剂 4-甲基伞形酮（4-MU 25mg/kg）处理损伤、假手术和未损伤动物。通过下一代测序评估粪便微生物群组成。通过免疫组织化学和生物分子方法（qRT-PCR 和 Western blot）评估小肠中性粒细胞浸润、HA 动态平衡和 toll 样受体（TLR2 和 TLR4）表达。在不存在和存在选择性 TLR2/4 抑制剂 Sparstolonin B（SsnB 10、30µM）的情况下，在体外研究神经肌肉反应。
4-MU 可显著降低 IRI 诱导的潜在有害细菌和细菌的过度生长。在 IRI 后，HA 水平、中性粒细胞浸润以及 TLR2 和 TLR4 的表达在 中显著增强，并且 4-MU 可将其显著降低至基础水平。在损伤组，但不在未损伤组和假手术组中，SsnB 降低了电刺激（EFS，0.1-40Hz）引起的收缩以及 EFS 诱导的（10Hz）非胆碱能非肾上腺素能舒张。
肠 IRI 后 HA 水平升高有利于有害细菌过度生长，增加中性粒细胞浸润，并促进 TLR2 和 TLR4 等细菌靶受体在 中的上调，从而引发炎症状态。然而，TLR2 和 TLR4 的激活可能对蠕动的兴奋性和抑制性神经元通路有暂时的益处。
