摘要目的 研究鼻腔给予exendin-4对海马内注射β淀粉样蛋白31-35(Aβ31-35)所致C57BL/6小鼠昼夜节律紊乱的影响及可能机制.方法 将C57BL/6小鼠按随机数字表法随机分为溶剂对照组、Aβ31-35组、exendin-4预处理组和exendin-4单独给药组.exendin-4采用鼻腔滴液的方式给药,Aβ31-35采用海马内注射的方法给药.利用动物自主跑轮行为学实验检测exendin-4对Aβ31-35引起的小鼠昼夜节律紊乱的影响.采用实时荧光定量PCR在分子水平检测exendin-4对Aβ31-35所致小鼠下丘脑视交叉上核节律基因per1及per2表达改变的作用.结果 exendin-4明显改善Aβ31-35所致小鼠昼夜节律紊乱.方差分析的结果显示,4组小鼠的自由运转周期是有差异的(F =4.355,P=0.014);海马内注射Aβ31-35引起小鼠自由运转周期[(23.7±0.08) h]延长,与溶剂对照组[(23.52±0.12)h]相比,差异具有统计学意义(P =0.007);exendin-4预处理后小鼠的自由运转周期[(23.53±0.11) h]明显短于Aβ31-35组,差异具有统计学意义(P=0.008).在持续黑暗环境下的昼夜时间14点时,per1在4组小鼠的表达量不同(F=3.105,P=0.047);Aβ31-35导致per1的表达(1.13±0.13)明显降低,与溶剂对照组(1.62±0.42)相比,差异具有统计学意义(P=0.025);exendin-4预处理后per1(1.58±0.39)的表达得到纠正.在持续黑暗环境下的昼夜时间8点时,per2在4组小鼠的表达量不同(F=3.273,P=0.043);Aβ31-35引起per2的表达(0.99 ±0.10)下降,与溶剂对照组(1.47±0.35)相比,差异具有统计学意义(P=0.016);exendin-4预处理明显改善per2异常表达,为1.40±0.38.结论 鼻腔给予exendin-4明显改善Aβ31-35所致C57BL/6小鼠昼夜节律紊乱,有可能是通过调整节律基因per1及per2的表达来实现的.

abstractsObjective To investigate the effects of intranasally administrated exendin-4 on the circadian rhythm disruption induced by amyloid β-protein fragment 31-35 (Aβ31-35) and its possible mechanisms.Methods The C57BL/6 mice were randomly divided into vehicle group,Aβ31-35 group,exendin-4 pretreatment group and exendin-4 group by random number table method.Exendin-4 was administrated by nasal drops,and Aβ31-35 was injected into hippocampus to observe the effects of exendin4 on circadian rhythm disruption induced by Aβ31-35 via the mouse wheel-running experiment,and to investigate the alteration of perl and per2 genes expression in the mouse suprachiasmatic nucleus caused by Aβ31-35 and exendin-4 via real-time PCR.Results Exendin-4 improved the circadian rhythm disruption induced by Aβ31-35.The free running periods of four groups were different by analysis of variance (F =4.355,P =0.014).The free running period treated by Aβ31-35 was (23.7 ± 0.08) h,which was obviously different comparing with the vehicle group ((23.52 ±0.12) h;P =0.007),and exendin-4 could reverse the alteration caused by Aβ31-35 ((23.53 ±0.11) h;P =0.008).There were different per1 mRNA expressions among four groups at circadian time 14 via analysis of variance (F =3.105,P =0.047).The perl mRNA relative level caused by Aβ31-35 (1.13 ± 0.13) was obviously lower than the vehicle group (1.62 ± 0.42;P =0.025),and the pretreatment with exendin-4 could ameliorate the alteration (1.58 ± 0.39).At circadian time 8,the expressions of per2 mRNA of four groups were obviously different by analysis of variance (F =3.273.P =0.043).Aβ31-35 caused per2 mRNA relative expression decreased (0.99 ± 0.10),which was obviously different comparing with the vehicle group (1.47 ± 0.35;P=0.016),and the pretreatment with exendin-4 could reverse the change (1.40 ± 0.38).Conclusion Intranasal administration of exendin-4 ameliorated the circadian rhythm disruption induced by Aβ31-35,which might relate to the regulation of per1 and per2 genes expression.