Nesfatin-1对肥胖大鼠胃排空及胃平滑肌条收缩性的影响

目的:观察Nesfatin-1对正常及单纯性肥胖大鼠胃排空及离体胃平滑肌条收缩活性的影响.方法:高脂饲料喂养♂大鼠6wk,制作单纯性肥胖大鼠模型;正常及肥胖大鼠实验组中枢注入不同浓度Nesfatin-1(0.5μmol/L、5μmol/L、50μmol/L)后测胃排空率;生理记录仪记录大鼠胃底、胃体平滑肌条自发收缩及不同浓度Nesfatin-1(0.026μmol/L、0.26μmol/L、2.6μmol/L)作用下对乙酰胆碱(Ach)诱导的肌条收缩的影响.结果:Nesfatin-1可抑制正常及肥胖大鼠胃平滑肌条收缩,低、中、高浓度组与生理盐水对照组相比差异均有统计学意义(q=3.93-15.72,P<0.05-0.01).随Nesfatin-1浓度的增高,其抑制作用呈明显剂量依赖关系(q=3.45-5.69,P<0.05-0.01).低浓度Nesfatin-1抑制正常大鼠、肥胖大鼠胃底平滑肌条收缩作用无显著性差异(P>0.05),中、高浓度对正常大鼠胃底平滑肌条抑制作用强于肥胖大鼠(t=2.14,P<0.05;t=2.63,P<0.05).低、中浓度Nesfatin-1抑制正常大鼠、肥胖大鼠离体胃体平滑肌条收缩作用无显著性差异(P>0.05),但高浓度抑制正常大鼠离体胃体平滑肌条收缩作用显著强于肥胖大鼠(t=2.53,P<0.05).结论:Nesfatin-1可抑制正常及肥胖大鼠胃排空,胃排空率随Nesfatin-1浓度增加而降低.Nesfatin-1可抑制乙酰胆碱诱导的单纯性肥胖大鼠离体胃平滑肌条的收缩活动,其抑制作用随Nesfatin-1浓度增高而增强;相同Nesfatin-1浓度抑制正常大鼠离体平滑肌条收缩作用强于肥胖大鼠.

Effect of Nesfatin-1 on gastric emptying and contraction of gastric smooth muscle strips in obese rats

AIM: To observe the impact of treatment with Nesfatin-1 on gastric emptying and stomach smooth muscle contraction in obese rats. METHODS: Obese rats were fed a high-nutrition diet for 6 weeks, while control rats were fed a normal diet. Different concentrations of Nesfatin-1 (0.5, 5, 50 μmol/L) were injected into the dorsal vagal complex (DVC). Gastric emptying was then determined, and the spontaneous contraction of isolated circular smooth muscle of gastric fundus and gastric body was recorded. In addition, the impact of different concentrations of Nesfatin-1 (0.026, 0.26, 2.6 μmol/L) on acetylcholine (Ach)-induced muscle contraction was observed. RESULTS: Various concentrations of Nesfatin-1 significantly inhibited the contraction of gastric smooth muscle strips isolated from both normal and obese rats compared to rats treated with normal saline (q = 3.93-15.72, all P < 0.05 or 0.01). Compared to normal rats, low-concentration Nesfatin-1 showed no significant relaxing effect on stomach fundus smooth muscle in obese rats (P > 0.05); however, medium and high concentrations of Nesfatin-1 significantly inhibited the contraction of gastric fundus smooth muscle of obese rats (t = 2.14, 2.63; both P < 0.05). Compared to normal rats, low and medium concentrations of Nesfatin-1 showed no significant relaxing effect on stomach corpus smooth muscle in obese rats (both P > 0.05); however, highconcentration Nesfatin-1 significantly inhibited the contraction of gastric corpus smooth muscle of obese rats (t = 2.53, P < 0.05). CONCLUSION: Nesfatin-1 inhibits gastric emptying in normal and obese rats and acetylcholineinduced gastric smooth muscle contraction in obese rats in a concentration-dependent manner. The inhibitory effect of Nesfatin-1 is stronger in normal rats than in obese ones.