Normal Reference Intervals of Neutrophil-To-Lymphocyte Ratio, Platelet-To-Lymphocyte Ratio, Lymphocyte-To-Monocyte Ratio, and Systemic Immune Inflammation Index in Healthy Adults: a Large Multi-Center Study from Western China.

BACKGROUND: Numerous studies have shown that the hematological components of the systemic inflammatory response, including the neutrophil-to-lymphocyte ratio (NLR), the platelet-to-lymphocyte ratio (PLR), the lymphocyte-to-monocyte ratio (LMR), and the systemic immune inflammation index (SII) are efficient prognostic indicators in patients with cancers. Most of the studies did not investigate the reference intervals (RIs) of these parameters in healthy controls. METHODS: A retrospective cohort study was performed on healthy ethnic Han population aged between 18 and 79 years of age by retrieving the data from a healthy routine examination center database and laboratory infor-mation system of four participating centers in western China. By following the Clinical and Laboratory Standards Institute (CLSI), RIs of each parameter was established and validated. RESULTS: The analysis included 5,969 healthy subjects. We found that the individual's gender can significantly influence PLR, LMR, and SII (all p < 0.05), but not NLR (p > 0.05). Surprisingly, we also found that with an increase in age, the PLR, LMR, and SII tend to decrease, while NLR remained stable. PLR, LMR, and SII values were significantly higher in the young adults (18 - 64 years) than in old adults (65 - 79 years) (p < 0.001). The RIs of NLR, PLR (adults), PLR (old adults), LMR and SII were 0.88 - 4.0, 49 - 198, 42 - 187, 2.63 - 9.9, 142 x 109/L - 804 x 109/L, respectively. CONCLUSIONS: Our study addresses possible variations and establishes consensus for the NLR, PLR, LMR, and SII RIs for healthy Han Chinese adults in western China. Further, established RIs can standardize clinical applications and promote the use of these indicators into the routine complete blood count report.

New Silent Cerebral Infarction in Patients with Acute Non-Cerebral Amyloid Angiopathy Intracerebral Hemorrhage as a Predictor of Recurrent Cerebrovascular Events.

BACKGROUND The aim of this study was to investigate the incidence and related risk factors of new silent cerebral infarction in patients with acute non-cerebral amyloid angiopathy (non-CAA) intracerebral hemorrhage (ICH) and to explore clinical cerebrovascular event recurrence within 1 year. MATERIAL AND METHODS This prospective study observed 152 patients with non-CAA ICH diagnosed by computed tomography within 3 days after onset. All patients underwent magnetic resonance imaging on day 14 to identify silent cerebral infarction, and their subsequent clinical cerebrovascular events were followed up regularly within 1 year. RESULTS Of the 152 patients, 46 (30.26%) had silent cerebral infarctions. Multiple logistic regression analysis revealed that the white blood cell (WBC) count, cerebral microbleeds (CMBs), and leukoaraiosis were silent cerebral infarction risk factors. At 1-year follow-up, 34 (22.37%) had clinical cerebrovascular events, with 8 (23.53%) having vascular-related deaths. Multiple logistic regression analysis showed that silent cerebral infarction was the only independent predictor of future clinical cerebrovascular events. CONCLUSIONS Silent cerebral infarction is common during acute non-CAA ICH and is independently related to WBC counts, CMBs, and leukoaraiosis. The risk of clinical cerebrovascular events in non-CAA ICH patients with silent cerebral infarction increases in the following year; thus, silent cerebral infarction may be a useful predictor of recurrent cerebrovascular events.

A Novel Method for Estimating Low-Density Lipoprotein (LDL) Levels: Total Cholesterol and Non-High-Density Lipoprotein (HDL) Can Be Used to Predict Abnormal LDL Level in an Apparently Healthy Population.

BACKGROUND We aimed to predict the abnormal LDL level by using TG, TC, HDL, and non-HDL in this study. MATERIAL AND METHODS Triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) data were obtained from the Laboratory Information System (LIS) for 4 years (Oct 1, 2013 to Sept 30, 2017) from among 34 270 healthy Chinese patients at Shuyang People's Hospital. TG, TC, HDL, and LDL (direct clearance method) were measured using a TBA2000FR biochemical analyzer. The non-HDL was calculated as TC minus HDL. Correlations between TG, TC, non-HDL, and LDL were analyzed using Spearman's rank correlation. Receiver operating characteristics (ROC) curve analysis was used to evaluate the predictive utility of TG, TC, and non-HDL for the abnormal LDL level (<130 mg/dL). RESULTS Both TC (r=0.870) and non-HDL (r=0.893) were significantly positively correlated with LDL. The area under curve of TC and non-HDL can be used to predict abnormal LDL levels. Optimal thresholds were 182.5 mg/Dl (4.72 mmol/L) for TC and 135.3 mg/Dl (3.50 mmol/L) for non-HDL. Based on these optimal thresholds, less than 0.5% and 0.4% of tests with elevated LDL were missed using TC and non-HDL, respectively, but the value of these missed LDL levels was not very high (<147.3 mg/dL). CONCLUSIONS If the value of non-HDL is less than 135.3 mg/Dl (3.50 mmol/L) and/or TC is less than 182.5 mg/Dl (4.72 mmol/L) for the apparently healthy populations, the LDL level will be less than 130 mg/Dl (3.36 mmol/L). TC and non-HDL can be used to predict the abnormal LDL level in apparently healthy populations.

Conjugated bilirubin as a reflex test for increased total bilirubin in apparently healthy population.

BACKGROUND: Total, unconjugated and conjugated bilirubin levels are usually ordered together in health check-up populations. The aim of this study was to investigate whether using increased total bilirubin (TBIL) as a reflex test can reduce conjugated bilirubin (CBIL) test. METHODS: Medical records of 8433 males and 4496 females who visited Shuyang People's Hospital for health check-ups were retrospectively reviewed and the fasting serum TBIL, unconjugated bilirubin (UBIL) and CBIL of patients were extracted. Reference intervals for TBIL, UBIL, CBIL and C/TBIL were established using Q2.5 to Q97.5 . The relationship between TBIL and CBIL was analyzed by Spearman's approach. Receiver operating characteristics (ROC) curve analysis was used to evaluate the predictive accuracy of TBIL for abnormal CBIL and UBIL. RESULTS: The reference intervals for TBIL in males and females were 6.9-29.3 µmol/L and 6.1-23.8 µmol/L, respectively. For CBIL, the reference intervals were 1.9-10.4 µmol/L and 1.6-8.8 µmol/L for males and females, respectively. CBIL was significantly positively correlated with TBIL, either in males (r=.75) or females (r=.73). Area under curve (AUC) of TBIL for predicting abnormal CBIL was 0.99 in both male and females. The optimal threshold of TBIL for predicting abnormal CBIL and UBIL were 21.0 µmol/L in males and 17.0 µmol/L in females. At these thresholds, <2% of subjects with abnormal CBIL or CBIL might be missed, but approximately 87% of the CBIL test could be eliminated. CONCLUSION: Conjugated bilirubin measurement is not needed for the apparently healthy males with TBIL <21.0 µmol/L or females with TBIL <17.0 µmol/L.

Reference intervals of carbohydrate antigen 19-9 in the apparently healthy adult population.

BACKGROUND: To establish reference intervals of carbohydrate antigen 19-9(CA 19-9) according to the CLSI CA28-A3 guideline and to evaluate age- and gender-related variations. METHODS: Serum CA 19-9 values of 10 149 healthy subjects (from 20 years old to 60 years old) were measured from location health checkups. The relationship between CA 19-9 and age was analyzed using Spearman's approach. The reference intervals of CA19-9 were established using Q2.5 and Q97.5 , and the 90% confidence intervals of upper limits were calculated. RESULTS: The reference intervals of CA 19-9 were 1.98-25.12 U/mL for males (1.97-25.06 U/mL for 20-50 years old and 2.31-26.13 U/mL for 50-60 years old) and 2.36-29.29 U/mL for adult (20-60 years old) females. The upper limit of reference intervals for all individuals was 26.45 U/mL; the level of CA 19-9 is higher in females than males. Carbohydrate antigen (CA) 19-9 is significantly associated with aging in adult males(r = .0930, P < .0001), but not in females (P = .4734). CONCLUSIONS: Establishing reference intervals for CA19-9 and giving age-related reference intervals of CA19-9 using a big data of healthy adult, we first discovered that CA19-9 tends to increase with age in adult males but not in females.

Limiting the testing of urea: Urea along with every plasma creatinine test?

BACKGROUND: We found that it is not necessary to simultaneously detect both creatinine (CREA) and urea until the concentration of CREA is lower than the certain level. To reduce urea testing, we suggest measuring urea only when CREA or estimated glomerular filtration rate (eGFR) exceeds a predetermined limit. MATERIALS AND METHODS: CREA and urea data were analyzed consisting of almost all of people age above 65 years old check-up (n=95441) in Shuyang countryside, and inpatients (n=101631), outpatients (n=18474) and Routine Health Check-up (n=20509) in Shuyang People's Hospital. The proportions of elevated urea were derived. The data used in this study was generated from people more than 13 years old in both outpatients and inpatients. RESULTS: When the limits for initiating urea testing were used at 85 µmol/L CREA and 120 mL/min/1.73 m2 eGFR, the percentage of unnecessary urea test are 94.5% and 64.7% (elderly health check-up), 67.9% and 84.5% (outpatients), 88.5% and 73.2% (inpatients), 92.2% and 81.7% (routine health check-up). The missing rate of urea are 1%, 2.5%, 4.6% and 9.2%, 0.1%, 0.4%, 0.9% and 1.8%, 0.4%, 0.8%, 1.4%, and 2.5%, 0.05%, 0.1%, 1.1%, and 0.8% of ureas exceeding 9.28 mmol/L and 8.3 mmol/L in above each group, respectively. If the CREA≤85 µmol/L or eGFR≥90 mL/min/1.73 m2 , there is 97.5% urea <10.1 mmol/L, the proportion of elevated urea missed is 2.5%. CONCLUSIONS: We suggest that the initiating urea testing should be based on the upper limit of Reference Intervals serum CREA of females or a 120 mL/min/1.73 m2 eGFR limit. Conservatively, the urea testing would be reduced by 65% at least.

Establishing Reference Intervals of Aspartate Aminotransferase-to-Platelet Ratio Index for Apparently Healthy Elderly.

BACKGROUND: Aspartate aminotransferase (AST) to platelet ratio index (APRI) serves as a parameter in evaluating liver fibrosis in current clinical practice. However, reference standard (reference intervals, RIs) or baseline levels of APRI have not been previously reported. The purpose of this paper is to establish the reference intervals of APRI in apparently healthy elderly people from the region of Shuyang, China. METHODS: Blood specimens were collected from local elderly residents (selected 51,263 elderly Han Shuyang Chinese from 65 to 97 years old, 32.97% males and 67.03% females) by standard procedures. Complete blood counts were determined by Sysmex XE-2100 analyzer and the AST values were measured by a TBA2000FR automatic biochemical analyzer (Toshiba Co., Ltd., Japan). The 95% reference intervals were calculated by using the non-parametric method according to the document: Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Guideline-Third Edition (C28-A3) of CLSI. RESULTS: RIs established for healthy elderly include: 0.1398-0.6266 for males and 0.1282-0.5798 for females (0.1284-0.5086 for 65-74 years old; 0.1209-0.5704 for > or = 75 years old). Ris of APRI for elderly males were higher than those of females, and values of APRI increased with increasing age for females. CONCLUSIONS: We established scientific and reasonable RIs of APRI for the healthy elderly in our region.

Reference Intervals of Alpha-Fetoprotein and Carcinoembryonic Antigen in the Apparently Healthy Population.

BACKGROUND The aim of this study was to calculate 95% reference intervals and double-sided limits of serum alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) according to the CLSI EP28-A3 guideline. MATERIAL AND METHODS Serum AFP and CEA values were measured in samples from 26 000 healthy subjects in the Shuyang area receiving general health checkups. The 95% reference intervals and upper limits were calculated by using MedCalc. RESULTS We provided continuous reference intervals from 20 years old to 90 years old for AFP and CEA. The reference intervals were: AFP, 1.31-7.89 ng/ml (males) and 1.01-7.10 ng/ml (females); CEA, 0.51-4.86 ng/ml (males) and 0.35-3.45ng/ml (females). AFP and CEA were significantly positively correlated with age in both males (r=0.196 and r=0.198) and females (r=0.121 and r=0.197). CONCLUSIONS Different races or populations and different detection systems may result in different reference intervals for AFP and CEA. Continuous reference intervals of age changes are more accurate than age groups.

Reference Intervals of Fibrosis Index Based on Four Indicators in Healthy Elderly Chinese.

BACKGROUND: The establishment of reference intervals of total bilirubin, Alanine aminotransferase (ALT), aspartate aminotransferases (AST), and creatinine provided necessary reference in screening and diagnosis of various kidney and liver diseases. However, these reference intervals were not available to estimate liver fibrosis degree. The purpose of this study is to establish the reference intervals of fibrosis index based on the four indicators (FIB-4) in apparently healthy elderly Chinese. METHODS: A total of 24,949 blood specimens were collected by the standard procedures, and ALT, AST, and PLT were determined. FIB-4 were calculated by the following formula: FIB-4 = (age [years] × AST [U/l])/((PLT [10(9) /l]) × (ALT [U/l])(1/2) ).The elderly's FIB-4 were analyzed between the same age of different sexes and different ages of the same sex. Statistical data were analyzed by SPSS18.0 software. RESULTS: Reference intervals of FIB-4 index, established for the healthy elderly, were 0.9923-4.5424 for males and 0.9007-4.1934 for females. CONCLUSION: We established reference intervals of FIB-4 index. This research provided reference value that can be used by relevant clinicians and inspection officers.

Laboratory reference intervals of complete blood count for apparently healthy elderly people in Shuyang, China.

BACKGROUND: Currently, there are no appropriate RIs of blood cells available for the elderly in most clinical laboratories in China. The aim of this study is to establish the RIs of complete blood cell count for apparently healthy elderly people. METHODS: Blood specimens were collected from elderly residents by standard procedures. Complete blood counts were determined by Sysmex XE-2100 analyzer. The RIs and 95% confidence intervals were calculated by the robust method recommended by CLSI C28-A3 guideline. RESULTS: RIs established for healthy elderly include: total WBC 3.63 - 10.3 x 10(9)/L for males and 3.64 - 10.3 x 10(9)/L for females; RBC 3.74 - 5.49 x 10(12)/L for males and 3.74 - 5.53 x 10(12)/L for females; Hb 109 - 167 g/L for males and 109 - 168 g/L for females; HCT 36.0 - 51.8% for males and 35.7 - 51.8% for females; MCV 86.0 - 105 fL for males and 86.2 - 106 fL for females; MCH 26.4 - 33.6 pg for males and 26.4 - 33.8 pg for females; MCHC 293 - 333 g/L for males and 291 - 335 g/L for females; RDW-SD 39.3 - 53.7 fL for males and 39.6 - 54.5 fL for females; RDW-CV 11.7 - 15.1% for males and 11.7 - 15.2% for females; PLT 122 - 355 x 10(9)/L for males and 122 - 350 x 10(9)/L for females; PCT 14.1 - 37.6 x 10(-1) mL/L for males and 13.9 - 37.9 x 10(-1) mL/L for females; MPV 11.3 - 15.5 fL for males and 11.3 - 15.5 fL for females; PDW 9.74 - 17.0% for males and 9.72 - 17.0% for females; platelet-LCR (P-LCR) 21.3 - 51.2% for males and 21.1 - 51.4% for females. CONCLUSIONS: We established scientific and reasonable RIs of blood cell analysis for the healthy elderly in our region.

Reference intervals for total bilirubin, ALT, AST and creatinine in healthy Chinese elderly.

BACKGROUND: The aim of this study was to establish the reference intervals (RIs) of total bilirubin (TBIL), alanine aminotransferase (ALT), aspartate transaminase (AST), and creatinine (CREA) for apparently healthy elderly (Han ethnicity) in Shuyang, China. MATERIAL AND METHODS: A total of 54 912 blood specimens from elderly residents age 65-104 years were collected by standard procedures in Shuyang county of Jiangsu province. TBIL, ALT, AST, and CREA for each participant were determined by automatic biochemical analyzer. Distribution and differences of TBIL, ALT, AST, and CREA were analyzed and compared between the elderly of the same age of different sexes and different ages of the same sex. RIs of TBIL, ALT, AST, and CREA were compared with the current RIs. The RIs and 95% confidence intervals were calculated using nonparametric method (2.5th-97.5th percentiles) according to the guideline of the Clinical and Laboratory Standards Institute. RESULTS: RIs established for the healthy elderly include: TBIL 7.8~30.6 µmol/L for males and 7.3~26.1 µmol/L for females; ALT 8.7~47.3 U/L for males and 8.4~45.2 U/L for females; AST 15.7~46.9 U/L for males and 15.1~46.2 U/L for females; and CREA 45.1~100.9 µmol/L for males and 38.7~85.0 µmol/L for females. Reference intervals of TBIL, ALT, AST, and CREA for male elderly were higher than those of females, and values of CREA increased with increasing age. CONCLUSIONS: We have established a panel of locally relevant RIs. It is necessary to establish scientific and reasonable RIs of TBIL, ALT, AST, and CREA for the healthy elderly in our region, which will provide a reference for clinicians and inspection officers.

Diagnostic value of Procalcitonin, C-reactive protein-to-lymphocyte ratio (CLR), C-reactive protein and neutrophil-to-lymphocyte ratio (NLR) for predicting patients with Bacteraemia in the intensive care unit.

BACKGROUND: To explore the diagnostic value of procalcitonin (PCT), C-reactive protein-to-lymphocyte ratio (CLR), C-reactive protein (CRP) and neutrophil-to-lymphocyte ratio (NLR) for predicting patients with bacteremia in the intensive care unit (ICU). METHODS: This case-control study included 359 patients with suspected bacteremia were divided into a bacteremia group (n = 152) and a control group (n = 207) from September 2018 to April 2023. Patient data were collected using a laboratory information system (LIS). ROC curves for PCT, CLR, CRP, and NLR in predicting patients with bacteremia. RESULTS: For PCT, CLR, CRP and NLR to predict patients with bacteremia in the ICU, the AUCs were 0.991(95%CI: 0.974-0.998), 0.960(95%CI: 0.935-0.978), 0.955(95%CI: 0.928-0.974), and 0.898(95%CI:0.862-0.927), respectively; the optimal thresholds were 0.248 ng/mL, 47.52 mg/109, 48.32 mg/L, and 6.51, respectively; the sensitivities were 95.4(95%CI: 90.7-98.1), 88.2(95%CI: 81.9-92.8), 87.5(95%CI: 81.2-92.3), and 86.8(95%CI:80.4-91.8), respectively; and the specificities were 95.7(95%CI: 91.9-98.0), 90.8(95%CI: 86.0-94.4), 90.3(95%CI: 85.5-94.0), and 85.0(95%CI:79.4-89.6), respectively. The sensitivities of PCT, CLR, CRP and NLR for predicting bacteremia due to E. coli infection are as high as over 90%, the specificity of PCT is 100, and the sensitivity of NLR is 100. The sensitivity of CRP for predicting bacteremia due to non-Enterobacer infection is 100. CONCLUSIONS: Compared with those in the control group, PCT, CLR, CRP and NLR were significantly greater in the bacteremia group. The PCT, CLR, CRP, and NLR can all predict the occurrence of bacteremia. The PCT had the highest sensitivity and specificity in predicting bacteremia in ICU patients.

A Novel LDLC Equation is Superior to the NIH LDLC Equation and the Friedewald Equation.

Background: LDLC equations have varying levels of underestimation for the calculated LDLC. Therefore, underestimating LDLC should be avoided as much as possible. We need to establish LDLC equations that underestimate LDLC as little as possible. Methods: We established the equations with a healthy cohort from Shuyang Hospital and validated the equations with an unselected patient cohort from The Second People's Hospital of Lianyungang. We established the novel LDLC equations by using the regression equation. The relationship between two markers was analysed using Pearson's approach. The 95% limits of measuring agreement within ±2 SD for the LDLC equations was performed using Bland‒Altman analysis. ROC curve analysis was used to predict LDLC levels and the accuracy of the LDLC equation for determining the direct LDLC levels at LDLC cut-offs was assessed. Results: We obtained two novel LDLC equations (LDL_nonHDLC equation=-0.899+1.195*nonHDLC-0.00347*nonHDLC2 and LDL_TC(total cholesterol) equation=-2.775+1.29*TC -0.00990* TC 2). The correlation coefficient between the novel LDLC equation and the direct LDLC measurements is not lower than that between the LDL_NIH equation and the direct LDLC measurements. The AUCs of our novel LDLC equations were greater than those of the LDL_NIH equation and the LDL_F equation at the LDLC cut-offs for clinical decision-making. The measuring agreement in the methods of the LDL_nonHDL equation is superior to that of the LDL_NIH equation. Conclusion: LDLC calculated by the novel LDL_nonHDL equation exhibited superiority over the LDL_NIH equation. Combining the LDL_NIH equation and our novel LDLC equation may improve accuracy and avoid undertreatment of high LDLC levels.

Effectiveness and safety of early lens extraction during par plana vitrectomy for proliferative diabetes retinopathy with mild cataract: a randomized clinical trial.

AIM: To evaluate the effectiveness and safety of early lens extraction during pars plana vitrectomy (PPV) for proliferative diabetic retinopathy (PDR) compared to those of PPV with subsequent cataract surgery. METHODS: This multicenter randomized controlled trial was conducted in three Chinese hospitals on patients with PDR, aged >45y, with mild cataracts. The participants were randomly assigned to the combined (PPV combined with simultaneously cataract surgery, i.e., phacovitrectomy) or subsequent (PPV with subsequent cataract surgery 6mo later) group and followed up for 12mo. The primary outcome was the change in best-corrected visual acuity (BCVA) from baseline to 6mo, and the secondary outcomes included complication rates and medical expenses. RESULTS: In total, 129 patients with PDR were recruited and equally randomized (66 and 63 in the combined and subsequent groups respectively). The change in BCVA in the combined group [mean, 36.90 letters; 95% confidence interval (CI), 30.35-43.45] was significantly better (adjusted difference, 16.43; 95%CI, 8.77-24.08; P<0.001) than in the subsequent group (mean, 22.40 letters; 95%CI, 15.55-29.24) 6mo after the PPV, with no significant difference between the two groups at 12mo. The overall surgical risk of two sequential surgeries was significantly higher than that of the combined surgery for neovascular glaucoma (17.65% vs 3.77%, P=0.005). No significant differences were found in the photocoagulation spots, surgical time, and economic expenses between two groups. In the subsequent group, the duration of work incapacity (22.54±9.11d) was significantly longer (P<0.001) than that of the combined group (12.44±6.48d). CONCLUSION: PDR patients aged over 45y with mild cataract can also benefit from early lens extraction during PPV with gratifying effectiveness, safety and convenience, compared to sequential surgeries.

[Differential judgment of coronary stenosis by 320-slice dynamic volume computed tomography and coronary angiography].

OBJECTIVE: To compare the characteristics of lesions with consistent and inconsistent judgments of coronary stenosis on 320-slice dynamic volume computed tomography (DVCT) versus coronary angiography (CAG). METHODS: Ninety-two patients (265 lesions) with CAG and DVCT within 2 weeks from January 2011 to May 2012 were enrolled. According to the matching degree of stenotic judgment, all lesions were divided into consistent and inconsistent groups. The position of lesions, degree of bending, plaque morphology and calcification proportion were analyzed. RESULTS: There were 236 lesions in consistent group versus 29 lesions in inconsistent group.In inconsistent group, there were more left circumflex artery, distal, ostial and tortuous lesions than that in consistent group (P < 0.05). At the same time, the proportion of nubbly type plaque, calcified plaque, nubbly and nodular type calcification in the main plaque in inconsistent group was higher than those in consistent group (P < 0.05).Segmental coronary calcium score (250 ± 210 vs 82 ± 66, P < 0.05), number of calcifications and calcification proportion in main plaque (55% ± 28% vs 43% ± 30%, P < 0.05) in inconsistent group were higher than those in consistent group (P < 0.05). CONCLUSION: When coronary lesion occurs in ostial, distal or tortuous position or its main plaque is of nubbly type with a heavy calcification load, the judgment of stenosis by CTA and CAG is more likely to be inconsistent.

[Pharmacological postconditioning with lactic acid and low dose edaravone could attenuate myocardial reperfusion injury through mitochondrial pathway].

OBJECTIVE: To test the hypothesis that pharmacological postconditioning with lactic acid and low dose edaravone could mimic the upper trigger of mechanical postconditioning and relieve reperfusion injury through mitochondrial pathway. METHODS: Rats were randomly divided into 6 groups (n = 18 each): sham, reperfusion/injury(I/R), postconditioning (IP), lactic acid (Lac, 60 µl), low dose edaravone (Eda, 3 µg/kg), and Lac+Eda. After 45 min myocardial ischemia, different drugs or saline were administrated around the infarct border according to different groups using micro syringe at the time of reperfusion. After 10 min reperfusion, right atrial plasma pH value was determined in all rats. Then the rats were sacrificed at 1, 6 and 24 h (n = 6 each), apoptotic index was measured by TUNEL, infarct area and ischemic area were measured through Evans blue-TTC double staining, mitochondrial absorbance, the contents of MDA and SOD in ischemic myocardium were detected by spectrophotometry, and the expression of apoptotic pathway molecules, such as Bcl-2, Bax and Cytochrome c (Cyt-c) , were detected by Western blot. RESULTS: Right atrial plasma pH value was significantly lower, the content of MDA was significantly lower, and the content of SOD was significantly higher in IP and Lac+Eda groups than in I/R group (all P < 0.05). The mitochondrial absorbance in Lac+Eda group at all time points were all significantly higher than those in I/R group (all P < 0.05). The level of Bcl-2 in ischemic myocardium in Lac+Eda group was significantly higher than in I/R group (1.02 ± 0.19 vs.0.02 ± 0.01, P < 0.05), the level of Bax (0.38 ± 0.07 vs.2.40 ± 0.45, P < 0.05) and Cyt-c(0.78 ± 0.05 vs.6.54 ± 1.86, P < 0.05) were all lower than those in I/R group. The content of CK[(849 ± 228) vs.(1249 ± 211) U/L, P < 0.05] and CK-MB[(470 ± 266) vs. (966 ± 263) U/L, P < 0.05] in Lac+Eda group were all significantly lower than in I/R group, apoptotic index [(10.51 ± 1.52)% vs. (15.00 ± 1.90) %, P < 0.05] and infarct area [(27.12 ± 5.55)% vs. (45.66 ± 10.81)%, P < 0.05] in Lac+Eda group were all significantly lower than those in I/R group. CONCLUSION: Pharmacological postconditioning with lactic acid and low dose edaravone could mimic the upper triggers of mechanical postconditioning and attenuate myocardial reperfusion injury through mitochondrial pathway.