Objective:To investigate the correlation between the expression of serum miR-125 b-5 p and homocysteine（Hcy）

hypersensitive C-reactive protein（Hs-CRP） and matrix metalloproteinase-9（MMP-9） in elderly patients with acute ischemic stroke（AIS）

and to provide evidence for the diagnosis and treatment of AIS.Methods:The study involved in 174 cases of AIS who admitted to the Third People’s Hospital of Hainan Province from January 2016 to May 2019.The National Institutes of Health Stroke Scale（NIHSS）score were used to divide the patients into mild group（n=5 1

NIHSS score<5 points）

moderate group（n=79

5 points≤NIHSS score≤20 points）

and severe group（n=44

NIHSS score>20 points）.Another 65 healthy subjects were selected as control group.Real-time fluorescent quantitative PCR was used to detect the expression of serum miR-125 b-5 p in each group.The diagnostic value of serum levels of miR-125 b-5 p

Hcy

Hs-CRP and MMP-9 for AIS patients were analyzed by ROC curve.Pearson correlation analysis was conducted to analyze the correlation of serum levels of miR-125 b-5 p with Hcy

Hs-CRP and MMP-9 in AIS patients.Results:The levels of serum miR-125 b-5 p[（2.74±0.95） vs.（0.68±0.13）]

Hcy[（19.26±5.37） μmol/L vs.（5.84±1.20） μmol/L]

HsCRP[（6.85±1.73） mg/L vs.（1.04±0.28） mg/L] and MMP-9[（150.75±30.82） μg/L vs.（78.62±11.40） μg/L] in AIS group were significantly higher than those in control group（t=14.217

P=0.000;t=13.475

P=0.000;t=10.624

P=0.000;t=9.806

P=0.000）.The serum levels of miR-125 b-5 [（4.10±1.18） vs.（2.62 ±0.84） and（1.70±0.53）]

Hcy[（28.35±6.80） μmol/L vs.（18.42±4.93） μmol/L and（11.50±3.27） μmol/L]

Hs-CRP[（11.92±3.25） mg/L vs.（6.14±1.57） mg/L and（2.76±0.63） mg/L] and MMP-9[（225.80±47.63） μg/L vs.（142.52±26.80） μg/L and（86.50±12.62） μg/L] in severe group were significantly higher than those in moderate group and mild group（F=10.845

P=0.000

F=8.716

P=0.000

F=5.184

P=0.003

F=4.972

P=0.010）.The AUC（95%CI） of serum miR-125 b-5 p in diagnosis of elderly AIS was0.846（0.787-0.903）

which was significantly higher than that of Hcy[0.754（0.693-0.812）]

Hs-CRP [0.728（0.672-0.788）] and MMP-9[0.695（0.634-0.753）].When the optimal critical value of miR-125 b-5 p was 2.10

the sensitivity and specificity were 88.0%and 80.7%.Relevant analysis showed that serum levels of miR-125 b-5 p were positively correlated with levels of Hcy

Hs-CRP and MMP-9 in elderly patients with AIS（r=0.836

0.745

0.702

P<0.01）.Conclusion:Serum miR-125 b-5 p expression level was significantly increased in AIS patients

and were correlated with Hcy

Hs-CRP and MMP-9 levels

which may be used as biomarkers for the diagnosis of AIS in elderly patients.