白芍总苷对慢性萎缩性胃炎大鼠胃黏膜的保护作用及机制

Protective effect and mechanism of total glucosides of paeony on gastric mucosa in rats with chronic atrophic gastritis

目的探讨白芍总苷对慢性萎缩性胃炎(CAG)大鼠胃黏膜的保护作用及其机制。方法从实验用SPF级SD大鼠中随机取24只作为正常组,其余123只大鼠采用N-甲基-N'-硝基-N-亚硝基胍(0.04 g/mL水溶液自由饮用)+雷尼替丁(0.03 g/kg灌胃,1次/d)+饥饱失常饮食(饱食2 d、禁食1 d)连续20周的方法构建CAG模型。将120只CAG造模成功大鼠随机分为模型组、维酶素组和白芍总苷低、中、高剂量组,每组24只。白芍总苷低、中、高剂量组分别给予白芍总苷75 mg/kg、150 mg/kg、300 mg/kg灌胃,维酶素组给予维酶素250 mg/kg灌胃,正常组和模型组灌胃等体积生理盐水,均1次/d,连续12周。检测各组大鼠胃黏膜血流量和血清胃泌素、血浆胃动素含量,HE染色和TUNEL染色观察胃黏膜病理学形态和细胞凋亡情况,ELISA法检测胃黏膜组织中肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、白细胞介素-8(IL-8)含量,Western blot法检测胃黏膜组织中Janus激酶2(JAK2)、p-JAK2、信号转导与转录激活子3(STAT3)、p-STAT3、核因子-κB(NF-κB)、B淋巴细胞瘤2(Bcl-2)、Bcl-2相关X蛋白(Bax)、Cleved Caspase-3蛋白表达情况。结果与模型组比较,白芍总苷各组和维酶素组大鼠胃黏膜血流量、血清胃泌素含量、血浆胃动素含量均明显升高(P均<0.05);腺体减少、萎缩、炎性细胞浸润等病理学改变明显改善,细胞凋亡减少,萎缩评分和细胞凋亡指数均明显降低(P均<0.05);胃黏膜组织中TNF-α、IL-6、IL-8含量明显降低;胃黏膜组织中p-JAK2、p-STAT3、NF-κB、Bax(除白芍总苷低剂量组)、Cleved Caspase-3蛋白相对表达量及p-JAK2/JAK2、p-STAT3/STAT3均明显降低(P均<0.05),Bcl-2蛋白相对表达量均明显升高(P均<0.05)。白芍总苷低、中、高剂量组上述作用呈现一定剂量依赖性,除胃黏膜血流量、萎缩评分外,白芍总苷高剂量组其余指标改善情况均明显优于维酶素组(P均<0.05)。结论白芍总苷能够明显提高CAG大鼠胃黏膜血流量和胃动力,减轻胃黏膜病变,作用机制可能与抑制JAK2/STAT3信号通路活化,减轻炎症损伤和抑制细胞凋亡有关。

Objective It is to investigate the protective effect of total glucosides of paeony(TGP)on gastric mucosa of rats with chronic atrophic gastritis(CAG)and explore its mechanism.Methods Twenty-four rats were randomly selected from experimental SPF-grade SD rats as the normal group,and the remaining 123 rats were treated with N-methyl-N’-nitro-N-nitrosoguanidine(MNNG,0.04 g/mL aqueous solution for free drinking)+ranitidine(0.03 g/kg by intragastrical administration,once a day)+starvation and satiety disorder diet(satiated for 2 d,fasted for 1 d)for 20 weeks to establish CAG models.120 successfully modeled CAG rats were randomly divided into model group,vitacoenzyme group,TGP low,medium,and high dose groups,with 24 rats in each group.The TGP low,medium and high dose groups were given TGP 75 mg/kg,150 mg/kg and 300 mg/kg by gavage,respectively,the vitacoenzyme group was given vitacoenzyme 250 mg/kg by gavage,and the normal group and model group were given equal volumes of normal saline by gavage,all once daily,continuously treated for 12 weeks.The gastric mucosal blood flow,the contents of serum gastrin and plasma motilin were detected,the gastric mucosal pathological changes and cell apoptosis were observe by HE and TUNEL staining respectively,the content of inflammatory factors[tumor necrosis factor-alpha(TNF-α),interleukin-6(IL-6),interleukin-8(IL-8)]in gastric mucosa were detected by ELISA,the protein expression of Janus kinase 2(JAK2),p-JAK2,signal transducer and activator of transcription 3(STAT3),p-STAT3,nuclear factorκB(NF-κB),B-lymphoma 2(Bcl-2),Bcl-2-associated X protein(Bax)and Cleved caspase-3 were detected by Western blot.Results Compared with the model group,the gastric mucosal blood flow,the contents of serum gastrin and plasma motilin of the rats in the vitacoenzyme group and each TGP group were significantly increased(all P<0.05);the pathological changes such as gland reduction,atrophy,inflammatory cell infiltration and cell apoptosis were significantly improved,the apoptotic cells were decreased,the cell atrophy score and cell apoptosis index were significantly reduced(all P<0.05);the contents of TNF-α,IL-6 and IL-8 in gastric mucosal tissues were significantly reduced;the relative expressions of p-JAK2,p-STAT3,NF-κB,Bax(except for the TGP low-dose group)and Cleved Caspase-3 proteins and the relative expressions of p-JAK2/JAK2 and p-STAT3/STAT3 in gastric mucosal tissues were significantly reduced(all P<0.05),and the relative expression of Bcl-2 protein were all significantly elevated(all P<0.05).All of the effects above in the TGP low,medium,high dose groups were dose-dependent,the improvements of these indexes except for the gastric mucosal blood flow and atrophy score in the TGP high dose groups were significantly better than those in the vitacoenzyme group(all P<0.05).Conclusion TGP can significantly increase mucosal blood flow,improve gastric motility and alleviate gastric mucosal lesions in CAG rats,and its mechanism may be related to inhibiting the activation of JAK2/STAT3 signaling pathway,and inhibiting inflammatory damage and apoptosis.