1.Role of NLRP3 inflammasome in therapeutic mild hypothermia post-treated myocardial ischemia-reperfusion rats
Yaqi LI ; Yixuan CHEN ; Jing ZHANG ; Shuchun YU
The Journal of Clinical Anesthesiology 2024;40(2):178-184
		                        		
		                        			
		                        			Objective To analyze the role of NOD-like receptor thermal protein domain associated protein 3(NLRP3)inflammasome in a therapeutic mild hypothermia(34℃)treated isolated rat myocardial ischemia-reperfusion model and explore its mechanism.Methods Sixty clean grade adult male SD rats,aged 7-10 weeks,weighing 250-300 g.Using a random number table method,the rats were divid-ed into five groups:blank control group(group S),myocardial ischemia-reperfusion group(group IR),34℃mild hypothermia post-treated myocardial ischemia-reperfusion group(group MH),34℃mild hypother-mia post-treated myocardial ischemia-reperfusion+3-TYP group(group HT),and 34℃mild hypothermia post-treated myocardial ischemia-reperfusion+3-TYP+MCC950 group(group HTM),12 rats in each group.Group S perfused the rat heart at 37℃with a balanced perfusion solution for 180 minutes.Group IR re-ceived balanced perfusion of the rat heart at 37℃for 30 minutes,followed by ischemia for 30 minutes and reperfusion with 37℃perfusion for 120 minutes.Group MH perfused the rat heart at 37℃for 30 minutes,followed by ischemia for 30 minutes and reperfusion with 34℃perfusion solution for 120 minutes.Group HT perfused the hearts of rats at 37℃for 30 minutes,followed by ischemia for 30 minutes,silent mating type information regulation 2 homolog 3(sirt3)inhibitor 3-TYP was added to the perfusate,and then per-fused at 34℃for 120 minutes.Group HTM perfused the hearts of rats at 37℃for 30 minutes,followed by ischemia for 30 minutes,sirt3 inhibitor 3-TYP and NLRP3 inhibitor MCC950 were added to the perfusate,and then perfused at 34℃for 120 minutes.The isolated heart was obtained 120 minutes after reperfusion,and the concentrations of IL-6 and IL-1β in the perfused cardiac fluid was measured using ELISA method,Western blot method for detecting the relative content of NLRP3 and sirt3 proteins in myocardial tissue,1%triphenyl tetrazolium chloride staining for calculating myocardial infarction area,and HE staining for observ-ing myocardial pathological changes.Results Compared with group S,HR were significantly slowed down,LVSP,±dp/dtmax were significantly decreased,and LVEDP were significantly increased 30,60,90,and 120 minutes after reperfusion,the concentrations of IL-6 and IL-1β in cardiac fluid leakage,and the per-centage of myocardial infarction area were significantly increased in groups IR,MH,HT,and HTM(P<0.05),the content of sirt3 protein in myocardial tissue were significantly reduced,while the content of NLRP3 protein were significantly increased in groups IR,HT,and HTM(P<0.05),the contents of sirt3 and NLRP3 protein in the myocardial tissue were significantly increased in group MH(P<0.05).Com-pared with group IR,HR were significantly increased,LVSP,±dp/dtmax were significantly increased,and LVEDP were significantly decreased 30,60,90,and 120 minutes after reperfusion,the concentrations of IL-6 and IL-1β in cardiac fluid leakage and the percentage of myocardial infarction area were significantly decreased in groups MH and HTM(P<0.05),the content of sirt3 protein in myocardial tissue was signifi-cantly increased,while the content of NLRP3 protein was significantly decreased in group MH(P<0.05),the content of NLRP3 protein in myocardial tissue was significantly reduced in group HTM(P<0.05).Compared with group MH,HR were significantly slowed down,LVSP,±dp/dtmax were significantly de-creased,and LVEDP were significantly increased 30,60,90,and 120 minutes after reperfusion,the con-centrations of IL-6 and IL-1β in cardiac fluid leakage,the percentage of myocardial infarction area,and the content of NLRP3 protein in myocardial tissue were significantly increased in group HT(P<0.05),the content of sirt3 protein in myocardial tissue was significantly reduced in groups HT and HTM(P<0.05).Compared with group HT,HR were significantly increased,LVSP,±dp/dtmax were significantly increased,and LVEDP were significantly decreased 30,60,90,and 120 minutes after reperfusion,the concentrations of IL-6 and IL-1β in cardiac fluid leakage,the percentage of myocardial infarction area,and the content of NLRP3 protein in myocardial tissue were significantly reduced in group HTM(P<0.05).Conclusion Therapeutic mild hypothermia(34℃)can improve hemodynamic parameters of isolated hearts and reduce the concentrations of IL-6 and IL-1β,NLRP3 protein content in myocardial tissue,percentage of myocardial infarction area,improve myocardial pathological changes,and reduce myocardial ischemia-reperfusion injury in rats,the mechanism may be related to the mitochondrial mediated sirt3 pathway inhibiting the high expres-sion of inflammatory corpuscle NLRP3.
		                        		
		                        		
		                        		
		                        	
2.Effects of biologics on psychological status and quality of life in patients with inflammatory bowel disease: a multicenter study
Shuchun WEI ; Chuan LIU ; Min CHEN ; Yanhui CAI ; Xiaohan WU ; Meilin CHEN ; Jixiang ZHANG ; Dan XIANG ; Zhongchun LIU ; Changqing JIANG ; Jie SHI ; Kaichun WU ; Weiguo DONG
Chinese Journal of Internal Medicine 2023;62(8):1000-1006
		                        		
		                        			
		                        			Objective:To investigate the effects of biologics on psychological status and quality of life in patients with inflammatory bowel disease (IBD).Methods:A cross-sectional survey was conducted in 42 hospitals in 22 provinces (autonomous regions and municipalities directly under the central government) from September 2021 to May 2022. General clinical information and the use of biologics were obtained from adult patients diagnosed with IBD who voluntarily participated in the study. Psychological status was evaluated using the Generalized Anxiety Disorder (GAD-7), Patient Health Questionnaire-9 (PHQ-9), Pittsburgh Sleep Quality Index (PSQI), and Inflammatory Bowel Disease Questionnaire (IBDQ) assessment tools. Counts were analyzed via the Chi-square test, and datasets that were not normally distributed were analyzed via nonparametric tests. P<0.05 was considered statistically significant. Results:A total of 2 478 valid questionnaires were collected. The GAD-7 score of the biologics group was significantly lower than that of the non-use group [6 (2, 9) vs. 7 (3, 10), Z=-3.49, P<0.001]. IBDQ scores [183 (158, 204) vs. 178 (152, 198), Z=-4.11, P<0.001], intestinal symptom scores [61 (52, 67) vs. 58 (49, 65), Z=-5.41, P<0.001], systemic symptom scores [28 (24, 32) vs. 27 (23, 31), Z=-2.37, P=0.018], emotional ability scores [69 (58, 77) vs. 67 (56, 75), Z=-3.58, P<0.001] and social ability scores [26 (22, 29) vs. 25 (22, 29), Z=-2.52, P=0.012] in the biologics group were significantly higher than in the non-use group. GAD-7 scores [5 (2, 9) vs. 6 (3, 10), Z=-3.50, P<0.001] and PSQI scores [6 (4, 9) vs. 6 (4, 9), Z=-2.55, P=0.011] were significantly lower in the group using infliximab than in the group not using it. IBDQ scores were significantly higher in patients using vedolizumab than in those not using it [186 (159, 205) vs. 181 (155, 201), Z=-2.32, P=0.021] and were also significantly higher in the group treated with adalimumab than in the group not treated with adalimumab [187 (159, 209) vs. 181 (155, 201), Z=-2.16, P=0.030]. However, ustekinumab had no significant effect on any of the scores. Conclusion:The use of biologics is strongly associated with improvements in anxiety status and quality of life in IBD patients.
		                        		
		                        		
		                        		
		                        	
3.Genomic and Transcriptomic Characterization Revealed the High Sensitivity of Targeted Therapy and Immunotherapy in a Subset of Endometrial Stromal Sarcoma
Nan KANG ; Yinli ZHANG ; Shichao GUO ; Ran CHEN ; Fangzhou KONG ; Shuchun WANG ; Mingming YUAN ; Rongrong CHEN ; Danhua SHEN ; Jianliu WANG
Cancer Research and Treatment 2023;55(3):978-991
		                        		
		                        			 Purpose:
		                        			The unique chromosomal rearrangements of endometrial stromal sarcoma (ESS) make it possible to distinguish high-grade ESS (HGESS) and low-grade ESS (LGESS) from the molecular perspective. Analysis of ESS at the genomic and transcriptomic levels can help us achieve accurate diagnosis of ESS and provide potential therapy options for ESS patients. 
		                        		
		                        			Materials and Methods:
		                        			A total of 36 ESS patients who conducted DNA- and/or RNA-based next-generation sequencing were retrospectively enrolled in this study. The molecular characteristics of ESS at genomic and transcriptomic levels, including mutational spectrum, fusion profiles, gene expression and pathway enrichment analysis and features about immune microenvironment were comprehensively explored. 
		                        		
		                        			Results:
		                        			TP53 and DNMT3A mutations were the most frequent mutations. The classical fusions frequently found in HGESS (ZC3H7B-BCOR and NUTM2B-YWHAE) and LGESS (JAZF1-SUZ12) were detected in our cohort. CCND1 was significantly up-regulated in HGESS, while the expression of GPER1 and PGR encoding estrogen receptor (ER) and progesterone receptor (PR) did not differ significantly between HGESS and LGESS. Actionable mutations enriched in homologous recombination repair, cell cycle, and phosphoinositide 3-kinase/AKT/mammalian target of rapamycin pathways were detected in 60% of HGESS patients. Genes with up-regulated expression in HGESS were significantly enriched in five immune-related pathways. Most HGESS patients (85.7%) had positive predictors of immunotherapy efficacy. Moreover, immune microenvironment analysis showed that HGESS had relatively high immune infiltration. The degree of immune infiltration in HGESS patients with ZC3H7B-BCOR fusion was relatively higher than that of those with NUTM2B-YWHAE fusion. 
		                        		
		                        			Conclusion
		                        			This study investigated the molecular characteristics of ESS patients at the genomic and transcriptomic levels and revealed the potentially high sensitivity of targeted therapy and immunotherapy in a subset of HGESS with specific molecular features, providing a basis for guiding decision-making of treatment and the design of future clinical trials on precision therapy. 
		                        		
		                        		
		                        		
		                        	
4.Characteristics of colonoscopy in patients aged 75 and above
Weihong CHEN ; Yanhua LI ; Ning DAI ; Lei ZHANG ; Shuchun QI ; Liming WANG
Chinese Journal of General Practitioners 2020;19(12):1164-1168
		                        		
		                        			
		                        			Objective:To analyze the characteristics of colonoscopy in patients aged 75 and above.Methods:The clinical data of 216 elderly patients aged 75 and above undergoing colonoscopy in our hospital from August 2015 to June 2019 were retrospectively analyzed. According to WHO criteria, there were 140 cases in aged group (75 to 89 years old) and 76 cases in the advanced aged group (90 years old and over). Demographic data, colonoscopy completion rate, bowel preparation quality, positive diagnosis rate and adverse events were analyzed and compared between the two groups.Results:More colonoscopies were performed under general anesthesia [7.9% (6/76) vs. 1.4% (2/140), χ 2=5.775, P<0.05] in the advanced aged group compared to the aged group, and the advanced aged group received lower doses of propofol and fentanyl when colonoscopies were administered with moderate sedation [(69.0±37.4) mg vs.(100.8±34.3)mg, t=6.302, P<0.01; (57.5±31.2) μg vs. (84.0±28.6)μg, t=6.297, P<0.01]. Colonoscopy completion was lower in the advanced aged group than that in the aged group[88.2%(67/76) vs. 99.3% (139/140), χ 2=13.815, P<0.01] and bowl preparation quality was worse [31.6%(24/76) vs. 15.0% (21/140), χ 2=8.209, P<0.05]. The proportion of adverse cardiopulmonary events [5.3%(4/76) vs. 0 (0/140), χ 2=7.507, P<0.01] and overall adverse events [9.2% (7/76) vs. 0.7% (1/140), χ 2=9.970, P<0.01] were higher in the advanced aged group than those in the elderly group. Colorectal cancer [14.5% (11/76) vs. 2.1% (3/140), χ 2=12.357, P<0.01] and advanced adenoma [27.6% (21/76) vs. 6.4% (9/140), χ 2=18.516, P<0.01] were more common in the advanced aged group than those in the aged group. Conclusion:Compared with the patients aged 75-89 years, patients aged 90 years and above have lower percentage of colonoscopy completion, lower quality of bowl preparation, and higher incidence of adverse events, and higher percentage of colorectal cancer and advanced adenomas detected.
		                        		
		                        		
		                        		
		                        	
5.Investigation and clinical analysis of a family with germline CEBPA mutations in acute myeloid leukemia
Junping ZHANG ; Dong LIN ; Shuchun WANG ; Yan LI ; Yumei CHEN ; Ying WANG ; Hui WEI ; Yingchang MI ; Jianxiang WANG
Chinese Journal of Hematology 2020;41(12):1008-1012
		                        		
		                        			
		                        			Objective:To investigate the clinical characteristics, etiology, and prognosis of familial acute myeloid leukemia (AML) with germline CEBPA mutation and improve the understanding of familial leukemia.Methods:The age of onset, clinical characteristics, outcome, and prognosis of a family of patients with AML were investigated, and the family tree of the cases was displayed. Bone marrow and oral mucosal cells were collected from the proband, and peripheral blood was collected from the relatives of the proband. Gene mutation was detected by gene sequencing technology.Results:A total of 10 patients in this family were diagnosed with acute leukemia, including 4 males and 6 females, with a median age of 9 (3-48) years. Of the 10 patients, six died. Among them, 4 patients did not receive treatment, 1 patient survived 3 years after chemotherapy and died of relapse, and one patient died 2 years after receiving traditional Chinese medicine and supportive treatment. Four patients are alive. One patient has survived 15 years through chemotherapy, and three patients have survived with chemotherapy combined with hematopoietic stem cell transplantation, and the survival time was 6, 9, and 28 months at the end of follow-up. Gene sequencing was performed on proband and 8 relatives of the proband, and 5 were found to have the germline CEBPA TAD p.G36Afs*124 mutation. Among the 5 individuals with confirmed CEBPA mutation, 4 were diagnosed with AML, and 1 had not developed disease during follow-up.Conclusion:AML with germline CEBPA gene mutation mostly occurs in children and young adults, with complete or nearly complete penetrance. With active treatment, most of the patients have a favorable prognosis.
		                        		
		                        		
		                        		
		                        	
6. Outcome of children with T cell acute lymphoblastic leukemia treated with Chinese Children Leukemia Group acute lymphoblastic leukemia (CCLG-ALL) 2008 protocol
Xiaoming LIU ; Xiaojuan CHEN ; Yao ZOU ; Shuchun WANG ; Min WANG ; Li ZHANG ; Yumei CHEN ; Wenyu YANG ; Ye GUO ; Xiaofan ZHU
Chinese Journal of Pediatrics 2019;57(10):761-766
		                        		
		                        			 Objective:
		                        			To evaluate the efficacy of the Chinese Children′s Leukemia Group (CCLG) acute lymphoblastic leukemia (ALL) 2008 protocol (CCLG-ALL 2008) in the treatment of children′s T-cell acute lymphoblastic leukemia (T-ALL).
		                        		
		                        			Methods:
		                        			Clinical characteristics and outcomes of 84 newly diagnosed T-ALL children (63 males and 21 females) treated with CCLG-ALL 2008 protocol from April 2008 to April 2015 in the Department of Pediatric Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences were analyzed retrospectively. Kaplan-Meier analysis was used to evaluate the overall survival (OS) and event free survival (EFS), and COX regression was used to evaluate the influencing factors of OS and EFS.
		                        		
		                        			Results:
		                        			(1) Baseline data: 84 children were included, 56 cases (67%) of children were younger than 10 years old. Patients whose white blood cell count≥50×109/L ranked 70% (59/84). Karyotype: 58% (49/84) with normal karyotype, 10% (8/84) with abnormality of chromosome 11, 8%(7/84) with abnormality of chromosome 9, 2%(2/84) with abnormality in both chromosome 11 and chromosome 9, 8% (7/84) with other complex karyotypes. Fusion gene: 33%(28/84) were SIL-TAL1 positive. The patients were grouped by CCLG-ALL 2008 risk score, 40% (34/84) were in the intermediate risk group and 60% (50/84) in the high risk group. (2) Treatment efficacy: 84 cases were followed up until May 30, 2018. The follow-up time was 42.0 (0.3-120.0) months. The sensitivity rate of prednisone treatment was 56% (47/84); the complete response (CR) rate after the induction therapy of vincristine+daunoblastina+L-asparaginase+dexamethasone (VDLD)(d 33) was 88% (74/84); the total CR rate after VDLD induction combined with cyclophosphamide+cytarabine+6-mercaptopurine (CAM) treatment (d80) was 94% (79/84); the recurrence rate was 24% (20/84). Among the 20 recurrent cases, there were 13 cases (65%) with ultra-early recurrence (within 18 months after diagnosis), 6 cases (30%) with early recurrence (18 to 36 months after diagnosis); 1 patient (5%) with late recurrence (over 36 months after diagnosis). During the follow-up period, twenty-eight children (33%) died (22 cases with recurrence or suspending treatment without remission, 2 cases with infection, 1 case of sudden death in chemotherapy, 1 patient failed in transplantation, 1 patient with severe cirrhosis, and 1 patient with unknown cause). (3) Kaplan-Meier analysis: the 5-year OS and EFS of the 84 children were (63±6)% and (60±6)% respectively. (4) Efficacy in different risk groups: prednisone sensitivity rates in the two different risk groups were 100% (34/34) and 26% (13/50), respectively (χ2=3.237, 
		                        		
		                        	
7.Protection effect of ATF-4 knockdown on fructose-induced steatosis in HepG2 cells
Luping REN ; Xian YU ; Na WANG ; Na LIU ; Guangyao SONG ; Shuchun CHEN
The Journal of Practical Medicine 2018;34(9):1424-1427,1434
		                        		
		                        			
		                        			Objective To investigate he intervention effect of knockdown of activating transcription factor 4(ATF-4)on fructose-induced lipid accumulation in liver cells. Methods HepG2 cells were divided into the control group(C),high fructose group(F),high-fructose+negative control group(F+NC)and high-fructose+ATF-4 siRNA group(F+ATF-4-). The mRNA level of gens of the upstream transcriptional factors and ERS markers was detected. The protein level of ACC,FAS and SCD-1 was also detected. Results Compared with group C,the mRNA expression of SREBP-1c,ChREBP,GRP78 and CHOP was increased(P < 0.01),while ATF-4 knock-down decreased the expression of the above genes(P < 0.01 ,respectively). Compared with group C ,the protein expression of ACC,FAS and SCD-1 was increased in group F(P<0.01,respectively). While ATF-4 knockdown decreased the protein expression of ACC ,FAS and SCD-1. Conclusions ATF-4 knockdown can improve the lipid steatosis induced by fructose through down-regulating lipid lipogenesis ,indicating ATF-4 possesses a regulatory effect on lipogenesis.
		                        		
		                        		
		                        		
		                        	
8.Role of SIRT1∕NF-κB signaling pathway in oxygen-glucose deprivation and restoration injury to hip-pocampal neurons of mice
Peng YAO ; Yong CHEN ; Yiling LI ; Shuchun YU ; Guohai XU
Chinese Journal of Anesthesiology 2018;38(9):1128-1131
		                        		
		                        			
		                        			Objective To evaluate the role of sirtuin 1 ( SIRT1)∕nuclear factor kappa B ( NF-κB) signaling pathway in oxygen-glucose deprivation and restoration ( OGD∕R) injury to hippocampal neurons of mice. Methods The HT22 hippocampal neurons were seeded in a culture plate ( 96-well plate, 100 μl∕well; 6-well plate, 2 ml∕well) at the density of 5×104 cells∕ml or in a culture dish (6 cm in diameter), and then divided into 4 groups ( n=24 each) using a random number table method: control group ( group C) , OGD∕R group ( group OGD) , SIRT1 inhibitor EX-527 preconditioning group ( group EX) and SIRT1 agonist SRT1720 preconditioning group ( group SRT) . Neurons were cultured in normal culture atmosphere at 37 ℃ in group C. In OGD, EX and SRT groups, the culture medium was replaced with oxygen-poor flu-id, and neurons were exposed to 5% CO2-95% N2 for 12 h in an incubator at 37℃, oxygen-poor fluid was replaced with the culture medium, and neurons were cultured for 24 h in normal culture atmosphere at 37℃. SIRT1 inhibitor EX-5271 μmol∕L and SIRT1 agonist SRT172010 μmol∕L were added at 12 h beforeOGD in EX and SRT groups, respectively. The cell viability was measured by CCK8 assay, the activity of LDH was detected by chemical colorimetry, cell apoptosis rate was determined by flow cytometry, the ex-pression of SIRT1, NF-κB, IκBα, Bcl-2 and Bax was detected by Western blot, and the Bcl-2∕Bax ratio was calculated. Results Compared with group C, the cell viability was significantly decreased, LDH ac-tivity and cell apoptosis rate were increased, the expression of SIRT1, IκBα and Bcl-2 was down-regula-ted, the expression of NF-κB and Bax was up-regulated, and the Bcl-2∕Bax ratio was decreased in OGD, EX and SRT groups ( P<0. 05) . Compared with group OGD, the cell viability was significantly increased, the LDH activity and cell apoptosis rate were decreased, the expression of SIRT1, IκBαand Bcl-2 was up-regulated, the expression of NF-κB and Bax was down-regulated, and the Bcl-2∕Bax ratio was increased in group SRT, and the cell viability was significantly decreased, LDH activity and cell apoptosis rate were in-creased, the expression of SIRT1, IκBαand Bcl-2 was down-regulated, the expression of NF-κB and Bax was up-regulated, and the Bcl-2∕Bax ratio was decreased in group EX (P<0. 05). Conclusion SIRT1∕NF-κB signaling pathway inhibition is involved in OGD∕R injury to hippocampal neurons of mice.
		                        		
		                        		
		                        		
		                        	
9. Heterogeneity and clonal evolution in pediatric ETV6-RUNX1+ acute lymphoblastic leukemia by quantitative multigene fluorescence in situ hybridization
Li ZHANG ; Linping HU ; Xiaoming LIU ; Ye GUO ; Wenyu YANG ; Jiayuan ZHANG ; Fang LIU ; Tianfeng LIU ; Shuchun WANG ; Xiaojuan CHEN ; Min RUAN ; Benquan QI ; Lixian CHANG ; Yumei CHEN ; Yao ZOU ; Xiaofan ZHU
Chinese Journal of Hematology 2017;38(7):586-591
		                        		
		                        			 Objective:
		                        			To evaluate heterogeneity and clonal evolution in pediatric ETV6-RUNX1+ acute lymphoblastic leukemia (ALL) in China.
		                        		
		                        			Methods:
		                        			Totally 48 children (<14 years) with newly diagnosed ETV6-RUNX1+ ALL in Institute of Hematology and Blood Disease Hospital, CAMS and PUMC, from February 2006 to June 2011 were included. The copy number variations were analyzed by quantitative multigene fluorescence in situ hybridization (QM-FISH) in 48 patients. Non-normal distribution of measurement data were shown with Median (range) , count data were shown with percent (%) . Overall survival and event-free survival were estimated by the Kaplan-Meier method and compared with the log-rank test.
		                        		
		                        			Results:
		                        			Forty-eight patients were tested by QM-FISH. Of 48 patients, 70.8% harbored one clone, 18.8% two subclones, and 10.4% three or more subclones. The clone heterogeneity was detected by two different models: the linear succession model and the branching evolution model. ETV6-RUNX1+ ALL relapse evolved from an ancestral clone or a new clone. The patients relapsed from a new clone got the worse outcome.
		                        		
		                        			Conclusion
		                        			The clone evolution was detected in pediatric ETV6-RUNX1+ ALL in China. QM-FISH might be helpful to evaluate the outcome of relapsed patients. A new clone was associated with a poorer outcome. 
		                        		
		                        		
		                        		
		                        	
10.Effects of age factors on hypothermia-induced reduction of ischemia-reperfusion injury in isolated rat hearts
Rong HU ; Yaqi LI ; Xiaolan HU ; Haili LANG ; Yong CHEN ; Zhidong ZHOU ; Jun YING ; Shuchun YU ; Guohai XU
Chinese Journal of Anesthesiology 2017;37(3):366-369
		                        		
		                        			
		                        			Objective To evaluate the effects of age factors on hypothermia-induced reduction of ischemia-reperfusion(I/R)injury in isolated rat hearts.Methods Pathogen-free healthy aged male Sprague-Dawley rats,aged 18-20 months,weighing 400-600 g,and young rats,aged 4-6 months,weighing 280-350 g,were used in the study.After the animals were anesthetized with intraperitoneal chloral hydrate and heparinized,their hearts were excised and perfused with K-H solution in a Langendorff apparatus.Twenty-four isolated hearts of aged rats were assigned into 2 groups(n=12 each)using a random number table:I/R group(group AI/R)and hypothermia group(group AH).Twenty-four isolated hearts of young rats were assigned into 2 groups(n=12 each)using a random number table:I/R group(group YI/R)and hypothermia group(group YH).Perfusion was suspended for 30 min followed by 120 min reperfusion to establish the model of I/R.The temperature was maintained at 37 ℃ during the whole process in AI/R and YI/R groups.The hearts were perfused with 34 ℃ K-H solution until 120 min of reperfusion starting from onset of reperfusion in AH and YH groups.At 30 min of equilibration(T0)and 15,30,60 and 120 min of reperfusion(T1-4),heart rate(HR),left ventricular developed pressure(LVDP),the maximum rate of increase in left ventricular pressure(+dp/dtmax),and the minimum rate of increase in left ventricular pressure(+dp/dtmin)were recorded.Six hearts from each group were randomly selected at T4,and myocardial specimens were obtained for determination of ATP,superoxide dismutase(SOD)and malondialdehyde(MDA)levels and myocardial infarct size(IS).Results Compared with group YI/R,HR was significantly decreased at T1-4,ATP and SOD levels were increased,and the MDA content and myocardial IS were decreased in group YH,and the HR,LVDP,+dp/dtmax and +dp/dtmin at T0 and ATP and SOD levels at T4 were significantly decreased,and the MDA content and myocardial IS were increased in group AI/R(P<0.05).Compared with group YH,HR,LVDP,+dp/dtmax and +dp/dtmin at T0 and ATP and SOD levels at T4 were significantly decreased,and the MDA content and myocardial IS were increased in group AH(P<0.05).Compared with group AH,the levels of ATP and SOD were significantly decreased,and the MDA content and myocardial IS were increased in group AI/R(P<0.05).Conclusion Age factors affect the efficacy of hypothermia in reducing I/R injury in isolated rat hearts,and hypothermia provides better cardioprotection for young rats than for aged rats.
		                        		
		                        		
		                        		
		                        	
            
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