补中益气汤对脾虚大鼠胃泌素受体结合作用的影响及其对胃粘膜损伤的保护机制

Effect of Buzhong Yiqi Decoction on Gastrin Receptor Combination and Its Protective Mechanism for Gastric Mucosa Damage in Spleen - Deficiency Rats

[目的]探讨补中益气汤对脾虚大鼠胃泌素受体结合作用的影响及其对胃粘膜损伤的保护机制。[方法]采用大黄灌胃建立脾虚大鼠模型,并采用补中益气汤灌胃治疗。用五肽胃泌素腹腔注射刺激胃酸分泌,用酸碱滴定法测定胃液总酸度,用本室改进的Pronase—EDTA消化翻转胃袋及Percoll线性密度梯度法分离纯化胃壁细胞,放射配基受体结合分析法观察胃壁细胞胃泌素受体的结合位点数及其亲和力;用Griess试剂法或紫外分光光度法检测胃粘膜组织的一氧化氮代谢产物(NO2-和NO3-)、过氧化亚硝酸(ONOO-)及一氧化氮合酶(包括结构型cNOS、诱导型iNOS)的活性。[结果]经胃泌素刺激后,脾虚大鼠胃液总酸度显著高于正常组;脾虚大鼠离体胃壁细胞胃泌素受体亲和力高于正常大鼠,但受体结合容量降低。经补中益气汤治疗后,脾虚大鼠胃泌素刺激后的胃液总酸度与正常组无显著性差异;离体胃壁细胞胃泌素受体亲和力降低,受体结合容量升高;补中益气汤含药血清能同125I-胃泌素竞争与大鼠胃壁细胞胃泌素受体特异性结合;脾虚大鼠胃粘膜组织中NO3-、iNOS及ONOO-水平均低于正常大鼠,经补中益气汤治疗后能恢复到接近正常水平。[结论]胃泌素受体亲和力升高是脾虚大鼠对刺激物的胃酸反应性升高的机理之一。此外,胃泌素保护粘膜作用相关的一氧化氮(NO)含量?

[Objective] To explore the effect of Buzhong Yiqi Decoction (BYD) on gastrin receptor combination and its protective mechanism for gastric mucosa damage in spleen - deficiency rats. [Methods] Spleen - deficiency rat models were induced by gastric infusion of Radix et Rhizoma Rhei decoction and were treated with BYD. Then, gastric acid se- cretion stimulated by gastrin in rats was observed; gastric juice acidity (GJA) was determined by acid- base titration; gastric parietal cells were isolated and purified by modified Pronase - EDTA - digestion reversed gastric sac method and Percoll linear - density gradient method; binding sites of gastric receptors and their affinity were analyzed by iodine - labeled 15 - Leu - gastrin - 17; concentrations of nitrite and nitrate (N02- and N03- ) and the activities of constitutive and inducible nitric oxide synthase (cNOS and iNOS) and peroxinitrites (ONOO- ) were observed with Griess reagent and ultraviolet spectrophotometry. [Results] After the stimulation of gastrin, gastric juice acidity was elevated, gastric receptor affinity increased and gastric receptor binding capacity reduced in spleen - deficiency rats as compared with those in normal rats. And after BYD treatment, gastric juice acidity arrived at normal level, gastric receptor affinity was decreased and gastric receptor binding capacity increased. Sero - BYD had a significant inhibitory effect on l251 - gastrin binding to gastrin receptors; gastric levels of N(>3 - , iNOS and ONOO - in spleen - deficiency rats were lower than those in normal rats and then arrived normal level after BYD treatment. [Conclusion] The increase of gastric receptor affinity may be one of the mechanisms of hyperactivity of gastric acid secretion after stimulation in rats with spleen deficiency. Competitive binding of BYD to gastrin receptor induce the decrease of receptor affinity and gastric acid secretion. The reduction of NO level indicates the decrease of preventive effect of gastric mucosa while BYD can increase NO level.