Department of Physiology, Faculty of Medicine, Jagiellonian University Medical College, 31-531 Cracow, Poland.
Int J Mol Sci. 2018 Sep 28;19(10):2960. doi: 10.3390/ijms19102960.
Carbon monoxide (CO) has been reported to contribute to the maintenance of gastric mucosal integrity, gastroprotection, and ulcer healing. However, involvement of transient receptor potential vanilloid receptor type 1 (TRPV1) located on afferent sensory fibers endings and sensory neuropeptide calcitonin gene-related peptide (CGRP) in CO-mediated gastroprotection against ethanol-induced gastric damage has not been explored. Male Wistar rats with and without denervation of afferent sensory neurons induced by capsaicin (total dose 125 mg/kg within 3 days) were pretreated with vehicle, CO donor tricarbonyldichlororuthenium (II) dimer (CORM-2, 5 mg/kg i.g.), administered alone or with CGRP-α (10 μg/kg i.p.) or TRPV1 antagonist capsazepine (5 mg/kg i.g.), followed 30 min later by intragastric (i.g.) administration of 75% ethanol. The area of gastric damage and gastric blood flow (GBF) were assessed planimetrically and by laser flowmetry, respectively. Microscopic evaluation of ethanol-induced gastric lesions was performed after haematoxylin/eosin (H&E) or alcian blue/periodic acid-Schiff/alcian blue (AB/PAS) staining. Gastric mucosal mRNA fold change for heme oxygenase (HMOX)-1, HMOX-2, CGRP-α, CGRP-β, inducible nitric oxide synthase (iNOS), endothelial (e)NOS, neuronal (n)NOS, cyclooxygenase (COX)-1, COX-2, and protein expression for HMOX-1 and TRPV1 was determined by real-time PCR or Western blot, respectively. Pretreatment with CORM-2 combined or not with CGRP reduced ethanol-induced gastric lesions and elevated GBF. Capsaicin-denervation or co-treatment with capsazepine or CGRP and CORM-2 in capsaicin-denervated animals failed to affect these beneficial effects of CO donor. In rats with intact sensory nerves, CORM-2 increased gastric mRNA level for HMOX-1 and CGRP-α. In capsaicin-denervated rats, CORM-2 increased eNOS mRNA fold change and TRPV1 protein expression while capsaicin denervation itself decreased HMOX-1 protein expression and eNOS mRNA level. We conclude that CO prevents gastric mucosa from ethanol-induced lesions due to activation of TRPV1/CGRP-α system and accompanying increase in gastric microcirculation but independently on afferent sensory nerve activity despite the stimulation of TRPV1 protein and CGRP-α mRNA expression.
一氧化碳 (CO) 已被报道有助于维持胃黏膜完整性、胃保护和溃疡愈合。然而,位于传入感觉纤维末梢的瞬时受体电位香草酸受体 1 (TRPV1) 和感觉神经肽降钙素基因相关肽 (CGRP) 在 CO 介导的对抗乙醇诱导的胃损伤的胃保护中的作用尚未得到探索。用辣椒素(3 天内总剂量 125mg/kg)对雄性 Wistar 大鼠进行感觉神经元传入感觉神经元去神经支配预处理,然后给予载体、一氧化碳供体三羰基二氯钌 (II) 二聚体 (CORM-2,5mg/kg 口服),单独或与 CGRP-α(10μg/kg 腹腔注射)或 TRPV1 拮抗剂辣椒素(5mg/kg 口服)联合给予,30 分钟后给予 75%乙醇灌胃。胃损伤面积和胃血流 (GBF) 通过平面测量和激光流量测量分别评估。通过苏木精/伊红 (H&E) 或阿尔辛蓝/过碘酸希夫/阿尔辛蓝 (AB/PAS) 染色评估乙醇诱导的胃损伤的显微镜评估。通过实时 PCR 或 Western blot 分别确定胃黏膜血红素加氧酶 (HMOX)-1、HMOX-2、CGRP-α、CGRP-β、诱导型一氧化氮合酶 (iNOS)、内皮 (e)NOS、神经元 (n)NOS、环加氧酶 (COX)-1、COX-2 和 HMOX-1 和 TRPV1 的蛋白表达的胃黏膜 mRNA 折叠变化。用 CORM-2 预处理,联合或不联合 CGRP-α,可减少乙醇诱导的胃损伤并增加 GBF。辣椒素去神经支配或与辣椒素去神经支配动物中的辣椒素、capsazepine 或 CGRP 和 CORM-2 联合治疗均不能影响 CO 供体的这些有益作用。在感觉神经完整的大鼠中,CORM-2 增加了胃黏膜 HMOX-1 和 CGRP-α 的 mRNA 水平。在辣椒素去神经支配的大鼠中,CORM-2 增加了 eNOS mRNA 折叠变化和 TRPV1 蛋白表达,而辣椒素去神经本身降低了 HMOX-1 蛋白表达和 eNOS mRNA 水平。我们得出结论,CO 通过激活 TRPV1/CGRP-α 系统并伴随胃微循环增加来防止胃黏膜免受乙醇诱导的损伤,但与传入感觉神经活动无关,尽管 TRPV1 蛋白和 CGRP-α mRNA 表达受到刺激。