Effect of Early Metformin Treatment on Long-term Cognitive Function in Prediabetic Rats after Transient Focal Cerebral Ischemia

doi:10.3969/j.issn.1673-5765.2018.08.015

Abstract

Abstract:

Objective To investigate the influence of prediabetes on post-stroke cognitive function and the effect of metformin treatment at the stage of prediabetes on cognitive decline after stroke. Methods Six-week-old male Wistar rats were fed with high-fat diet to build prediabetes models. Prediabetes rats were given metformin treatment of 12 weeks [200 mg/(kg·d), intraperitoneal injection] from an age of 10 weeks, and the rats were subjected to a 90-minute right middle cerebral artery occlusion (MCAO) at an age of 14 weeks. Rotarod tests were performed to evaluate motor coordination function in prediabetes rats at an age of 15 and 20 weeks, and then Morris water maze tests were conducted to evaluate these rats’ cognitive function at an age of 21 weeks. The levels of fasting blood glucose and serum insulin were measured using blood glucose test strips and ELISA assay. Results Prediabetes rats had more worse long-term neurological function and ability of spatial learning and memory after MCAO than rats without prediabetes. Early metformin treatment could alleviate cognitive decline after stroke in prediabetes rats. The rats treated with metformin had lower concentration of blood glucose and serum insulin than rats treated with saline. Conclusions Early metformin treatment in the stage of prediabetes could alleviate long-term cognitive decline after stroke, which is probably associated with the lower level of blood glucose and insulin due to metformin.

Key words: Prediabetes; Stroke; Cognitive function; Metformin; Neurological function

摘要：

目的研究糖尿病前期对短暂局灶脑缺血后长期认知功能的影响，以及早期二甲双胍治疗的效果。

方法给予6周龄的雄性Wistar大鼠高脂饮食构建糖尿病前期模型。糖尿病前期大鼠在10周龄时给予为期12周的二甲双胍治疗[200 mg/（kg·d），腹腔注射]。14周龄时进行90 min大脑中动脉闭塞（middle cerebral artery occlusion，MCAO）术。分别在15、20周龄时进行Rotarod旋转棒实验评估运动功能。21周龄时进行Morris水迷宫实验评估认知功能。通过血糖检测试纸和ELISA的方法分别检测空腹血糖和血清胰岛素水平。

结果糖尿病前期大鼠在MCAO术后其长期神经功能以及空间学习记忆能力较无糖尿病前期大鼠更差。早期二甲双胍治疗可改善糖尿病前期合并卒中后的认知功能障碍。二甲双胍治疗大鼠的空腹糖和空腹胰岛素水平较生理盐水治疗更低。

结论在糖尿病前期即启动二甲双胍治疗可减轻后期卒中导致的长期认知功能障碍，这可能与降低血糖和胰岛素水平有关。

关键词: 糖尿病前期; 卒中; 认知功能; 二甲双胍; 神经功能

LI Jie-Jie, PENG Yu-Jing, WANG Yong-Jun. Effect of Early Metformin Treatment on Long-term Cognitive Function in Prediabetic Rats after Transient Focal Cerebral Ischemia[J]. Chinese Journal of Stroke, 2018, 13(08): 834-839.

黎洁洁, 彭玉晶, 王拥军. 早期二甲双胍治疗对糖尿病前期合并短暂局灶脑缺血后长期认知功能的影响[J]. 中国卒中杂志, 2018, 13(08): 834-839.

References

[1] GARCIA-ALLOZA M，GREGORY J，

KUCHIBHOTLA K V，et al. Cerebrovascular lesions

induce transient beta-amyloid deposition[J]. Brain，

2011，134（Pt 12）：3697-3707.

[2] LIN M S，CHIU M J，WU Y W，et al.

Neurocognitive improvement after carotid artery

stenting in patients with chronic internal carotid

artery occlusion and cerebral ischemia[J]. Stroke，

2011，42（10）：2850-2854.

[3] IRIE F，FITZPATRICK A L，LOPEZ O L，et al.

Enhanced risk for alzheimer disease in persons

with type 2 diabetes and apoe epsilon4：The

cardiovascular health study cognition study[J]. Arch

Neurol，2008，65（1）：89-93.

[4] LI J，SHENG W，FENG C，et al. Pyrrolidine

dithiocarbamate attenuates brain abeta increase and

improves long-term neurological outcome in rats

after transient focal brain ischemia[J]. Neurobiol Dis，

验室研究方面，既往研究表明，二甲双胍可通

过促进神经再生改善空间学习记忆能力[24]。本

课题组前期研究同样表明，二甲双胍可改善糖

尿病大鼠颅内AD样的病理改变[5]。在本研究中，

在糖尿病前期之后以及卒中发生前使用二甲双

胍，模拟了临床常见的患者状态，结果发现二

甲双胍能改善糖尿病前期合并缺血性卒中后认

知功能障碍。糖-能量代谢状态和Aβ蛋白，tau

蛋白以及神经再生有关[25]，本研究检测了相关

生化指标，发现二甲双胍可降低空腹血糖。另

一方面，临床研究表明二甲双胍可改善卒中结

局[26 -27]，而基础研究表明二甲双胍可减小梗死

体积[28-30]。因此，本研究所观察到的二甲双胍

对认知功能的影响可能与降低血糖、保护脑组

织有关，这还需要后续的研究加以证实。

本研究存在以下局限性：首先，为了减

少动物的死亡率，本研究采用缺血90 m i n的

MCAO模型，这只能模拟一部分的临床卒中患

者；其次，二甲双胍对缺血的基底节区或者远

端和记忆有关的海马区的组织病理改变有何影

响，本研究并没有涉及，需要后续研究进一步

阐述。

2012，45（1）：564-572.

[5] LI J，DENG J，SHENG W，et al. Metformin

attenuates alzheimer's disease-like neuropathology

in obese，leptin-resistant mice[J]. Pharmacol

Biochem Behav，2012，101（4）：564-574.

[6] ZHANG T，PAN B S，ZHAO B，et al. Exacerbation

of poststroke dementia by type 2 diabetes is

associated with synergistic increases of betasecretase

activation and beta-amyloid generation in

rat brains[J]. Neuroscience，2009，161（4）：1045-

1056.

[7] American Diabetes Association. Standards of

medical care in diabetes--2014[J]. Diabetes Care，

2014，37（Suppl 1）：S14-S80.

[8] JIA Q，ZHENG H，ZHAO X，et al. Abnormal

glucose regulation in patients with acute stroke

across china：Prevalence and baseline patient

characteristics[J]. Stroke，2012，43（3）：650-657.

[9] HO L，QIN W，POMPL P N，et al. Diet-induced

insulin resistance promotes amyloidosis in a

transgenic mouse model of alzheimer's disease[J].

FASEB J，2004，18（7）：902-904.

[10] MORRIS R. Developments of a water-maze

procedure for studying spatial learning in the rat[J].

J Neurosci Methods，1984，11（1）：47-60.

[11] TULIGENGA R H，DUGRAVOT A，TABáK A G，

et al. Midlife type 2 diabetes and poor glycaemic

control as risk factors for cognitive decline in early

old age：A post-hoc analysis of the whitehall ii

cohort study[J]. Lancet Diabetes Endocrinol，2014，2

（3）：228-235.

[12] BUYSSCHAERT M，BERGMAN M. Definition of

prediabetes[J]. Med Clin North Am，2011，95（2）：

289-297.

[13] American Diabetes Association. Diagnosis and

classification of diabetes mellitus[J]. Diabetes Care，

2013，36（Suppl 1）：S67-S74.

[14] FONVILLE S，ZANDBERGEN A A，

KOUDSTAAL P J，et al. Prediabetes in patients with

stroke or transient ischemic attack：Prevalence，risk

and clinical management[J]. Cerebrovasc Dis，2014，

37（6）：393-400.

[15] FORD E S，ZHAO G，LI C. Pre-diabetes and the

risk for cardiovascular disease：A systematic review

of the evidence[J]. J Am Coll Cardiol，2010，55（13）：

1310-1317.

[16] LEE M，SAVER J L，HONG K S，et al. Effect

of pre-diabetes on future risk of stroke：Metaanalysis[

J/OL]. BMJ，2012，344：e3564. https：//doi.

org/10. 1136/bmj. e3564.

[17] RAWLINGS A M，SHARRETT A R，SCHNEIDER A L，et al. Diabetes in midlife and cognitive change

over 20 years：A cohort study[J]. Ann Intern Med，

2014，161（11）：785-793.

[18] KNOWLER W C，BARRETT-CONNOR E，

FOWLER S E，et al. Reduction in the incidence

of type 2 diabetes with lifestyle intervention or

metformin[J]. N Engl J Med，2002，346（6）：393-

403.

[19] Diabetes Prevention Program Research Group. The

10-year cost-effectiveness of lifestyle intervention or

metformin for diabetes prevention：an intent-to-treat

analysis of the DPP/DPPOS[J]. Diabetes care，2012，

35（4）：723-730.

[20] MOORE E M，MANDER A G，AMES D，et al.

Increased risk of cognitive impairment in patients

with diabetes is associated with metformin[J].

Diabetes Care，2013，36（10）：2981-2987.

[21] HSU C C，WAHLQVIST M L，LEE M S，et

al. Incidence of dementia is increased in type 2

diabetes and reduced by the use of sulfonylureas and

metformin[J]. J Alzheimers Dis，2011，24（3）：485-

493.

[22] NG T P，FENG L，YAP K B，et al. Long-term

metformin usage and cognitive function among older

adults with diabetes[J]. J Alzheimers Dis，2014，41

（1）：61-68.

[23] BEERI M S，SCHMEIDLER J，SILVERMAN J

M，et al. Insulin in combination with other diabetes

medication is associated with less alzheimer

neuropathology[J]. Neurology，2008，71（10）：750-

757.

[24] WANG J，GALLAGHER D，DEVITO L M，et al.

Metformin activates an atypical pkc-cbp pathway to

promote neurogenesis and enhance spatial memory

formation[J]. Cell Stem Cell，2012，11（1）：23-35.

[25] SATO N，MORISHITA R. The roles of lipid and

glucose metabolism in modulation of beta-amyloid，

tau，and neurodegeneration in the pathogenesis of

alzheimer disease[J/OL]. Front Aging Neurosci，2015，

7：199. https：//doi.org/10.3389/fnagi.2015.00199.

[26] UKPDS Group. Effect of intensive blood-glucose

control with metformin on complications in

overweight patients with type 2 diabetes（UKPDS

34）. UK Prospective Diabetes Study（UKPDS）

Group[J]. Lancet，1998，352（9131）：854-865.

[27] MIMA Y，KUWASHIRO T，YASAKA M，et al.

Impact of metformin on the severity and outcomes of

acute ischemic stroke in patients with type 2 diabetes

mellitus[J]. J Stroke Cerebrovasc Dis，2016，25（2）：

436-446.

[28] LIU Y，TANG G，LI Y，et al. Metformin

attenuates blood-brain barrier disruption in mice

following middle cerebral artery occlusion[J/OL].

J Neuroinflammation，2014，11：177. https：//doi.

org/10.1186/s12974-014-0177-4.

[29] LI J，BENASHSKI S E，VENNA V R，et al. Effects

of metformin in experimental stroke[J]. Stroke，2010，

41（11）：2645-2652.

[30] HARADA S，FUJITA-HAMABE W，TOKUYAMA

S. The importance of regulation of blood glucose

levels through activation of peripheral 5'-ampactivated

protein kinase on ischemic neuronal

damage[J/OL]. Brain Res，2010，1351：254-263. https：//doi.org/10.1016/j.brainres.2010.06.052.