兔眼晶体机械性损伤后超氧化物歧化酶活性测定

采用连苯三酚自氧化法对兔晶体机械性损伤后不同时间晶体ＳＯＤ活性进行测定，发现机械性损伤后晶体ＳＯＤ活性显著性下降，晶体的抗Ｏ２的能力明显下降。提示晶体机械性损伤后有Ｏ２大量生成，晶体的抗氧化能力下降。自由基损伤是晶体损伤后外伤性白内障形成的重要因素之一。

Relationship between the Hypersensitive Response of Wheat to Blumeria graminis f. sp. tritici and Hydrogen Peroxide,Three Enzyme Activities Changes

[Objective] The research aimed to study the relationship between the hypersensitive response of wheat to Blumeria graminis f.sp.tritici and hydrogen peroxide,3 enzyme activities changes and lay the foundation for discussing the resistant physiological mechanism of wheat to B.graminis.[Method] Taking B.graminis Bgt 17 and Bgt 6 and wheat cultivar Yang 158 as test materials,the number of hypersensitive cells and activities of POD,PPO and SOD in wheat leaves treated by H2O2 were determined.[Result] The mastoid...

The influence of cadmium on the antioxidant enzyme activities in polychaete Perinereis aibuhitensis Grube(Annelida:Polychaeta)

The infaunal polychaete Perinereis aibuhitensis Grube,distributed widely along Asian coasts and estuaries,is considered a useful animal model in ecotoxicological tests and a promising candidate in biomonitoring programs.This paper deals with the activities of antioxidant enzymes including superoxide dismutase(SOD),catalase(CAT),and glutathione peroxidases(GSH-Px) in infaunal polychaete P.aibuhitensis exposed to a series of sublethal water-bound cadmium(Cd) concentrations(0,0.34,1.72,3.44,6.89,and 17.22 mg L-1) under a short-term exposure(1-8 d).The results indicate that the SOD and GSH-Px activities in P.aibuhitensis are stimulated first and then renewed to the original level.The CAT activity of worms decreases at an earlier exposure time but increases to the control values at a later exposure time.Our study suggests that Cd can interfere with the antioxidant defense system of P.aibuhitensis.However,the changes in antioxidant enzyme activities for this species do not show the best promise as biomarkers in Cd biomonitoring of estuarine and coastal zones because weak or non-dose-effect relationships between the antioxidant enzymes activities and Cd levels are found.

Effects of benzo(a)pyrene exposure on the antioxidant enzyme activity of scallop Chlamys farreri

Scallop Chlamys farreri was exposed to different concentrations of benzo(a)pyrene (BaP) (0.5 μg/L, 1.0 μg/L, 10.0 μg/L and 50.0 μg/L) for 30 days in seawater. The 7-ethoxyresorufin O-deethylase (EROD) activity was significantly induced, and increased with the increasing BaP concentration. The glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), Glutathione peroxidase (GPx) activities increased in short time at low concentration of BaP, and was significantly depressed at high concentrations. Scallop gill was more sensitive to BaP than the digestive gland, and the digestive gland was the main tissue to deal with oxyradicals. The contents of malondialdehyde (MDA) increased with the exposure time and there was a positive correlation (concentration-effect) between the MDA content and the concentration of BaP. The biomarkers determined in this experiment had important roles in detoxification, and showed great potential as biomarkers for oxidative stress. Controlled laboratory experiments designed to simulate field exposure scenarios are particularly useful in ascertaining biomarkers suitable for use with complex contaminant mixtures in the marine environment.

The Antioxidant Effects of Complexes of Tilapia Fish Skin Collagen and Different Marine Oligosaccharides

An excess of reactive oxygen species（ROS）leads to a variety of chronic health problems.As potent antioxidants,marine bioactive extracts containing oligosaccharides and peptides have been extensively studied.Recently,there is a growing interest in protein-polysaccharide complexes because of their potential uses in pharmaceutical and food industries.However,only few studies are available on the antioxidant activities of such complexes,in terms of their ROS scavenging capability.In this study,we combined and superoxide radicals,and to evaluate the influences on the activities of superoxide dismutase（SOD）,glutathione peroxidase（GSH-Px）and the level of malondialdehyde（MDA）in UV-induced photoaging models.The results indicated that the antioxidant activities of all the complexes were stronger than those of their individual components.Among the 11 complexes tested,two complexes,namely MA1000＋CP and κ-ca3000＋CP,turned out to be highly effective antioxidants.Although the detailed mechanisms of this improved scavenging ability are not fully understood,this work provides insights into the design of highly efficient peptide-oligosaccharide complexes for potential applications in pharmaceutical,cosmetics and food industries.

Proteasome inhibitor treatment in alcoholic liver disease

Oxidative stress, generated by chronic ethanol consumption, is a major cause of hepatotoxicity and liver injury. Increased production of oxygen-derived free radicals due to ethanol metabolism by CYP2E1 is principally located in the cytoplasm and in the mitochondria, which does not only injure liver cells, but also other vital organs, such as the heart and the brain. Therefore, there is a need for better treatment to enhance the antioxidant response elements. To date, there is no established treatment to attenuate high levels of oxidative stress in the liver of alcoholic patients. To block this oxidative stress, proteasome inhibitor treatment has been found to significantly enhance the antioxidant response elements of hepatocytes exposed to ethanol. Recent studies have shown in an experimental model of alcoholic liver disease that proteasome inhibitor treatment at low dose has cytoprotective effects against ethanol-induced oxidative stress and liver steatosis. The beneficial effects of proteasome inhibitor treatment against oxidative stress occurred because antioxidant response elements （glutathione peroxidase 2, superoxide dismutase 2, glutathione synthetase, glutathione reductase, and GCLC） were upregulated when rats fed alcohol were treated with a low dose of PS-34Z （Bortezomib, Velcade）. This is an important finding because proteasome inhibitor treatment up-regulated reactive oxygen species removal and glutathione recycling enzymes, while ethanol feeding alone down-regulated these antioxidant elements. For the first time, it was shown that proteasome inhibition by a highly specific and reversible inhibitor is different from the chronic ethanol feeding-induced proteasome inhibition. As previously shown by our group, chronic ethanol feeding causes a complex dysfunction in the ubiquitin proteasome pathway, which affects the proteasome system, as well as the ubiquitination system. The beneficial effects of proteasome inhibitor treatment in alcoholic liver disease are related to proteasome inhibitor reversibility and the rebound of proteasome activity 72 h post PS-341 administration.

Chitosan Oligosaccharide-Ca Complex Accelerates the Depuration of Cadmium from Chlamys ferrari

This study investigated the effect of a chitosan oligosaccharide-Ca complex (COS-Ca) on the depuration of cadmium (Cd) from Chlamys ferrari. After exposure to 0.5 mg L-1 CdCl2 for 3 or 7 d, the scallops were treated by COS-Ca prior to determina-tion of Cd, calcium (Ca) and zinc (Zn) contents, Cd distribution in organs, malondialdehyde (MDA) content and antioxidant variables. Results showed that COS-Ca reduced Cd content in the viscera of the scallops, with highest Cd depuration rate (47%) observed on day 3. The COS-Ca concentration substantially affected Cd depuration, and the exposure to 8.75 mg L-1 COS-Ca led to significantly higher Cd depuration rate compared with those of lower COS-Ca concentrations (1.75, 3.5, 5.25, and 7.00 mg L-1). Distribution analysis of Cd in scallop organs indicated that COS-Ca significantly reduced Cd content in the kidney throughout the 5-d experiment, as well as in the gill during the early stage of Cd depuration. In addition, COS-Ca treatment decreased glutathione peroxidase (GSH-Px) activity and MDA content while increasing superoxide dismutase (SOD) and catalase (CAT) activities on different days. Our work suggested COS-Ca complex treatment as an effective method for acceleration of Cd depuration from Cd-contaminated bivalves.

Effects of dietary menadione on the activity of antioxidant enzymes in abalone, Haliotis discus hannai Ino

A 240-day growth experiment in a re-circulating water system was conducted to investigate the effects of dietary menadione on the growth and antioxidant responses of abalone Haliotis discus hannai Ino. Triplicate groups of juvenile abalone (initial weight: 1.19 ± 0.01 g; shell length: 19.23 ± 0.01 mm) were fed to satiation with 3 semi-purified diets containing 0, 10, and 1 000 mg menadione sodium bisulfite (MSB)/kg, respectively. Results show that there were no significant differences in the rate of weight gain or in the daily increment in shell length of abalone among different treatments. Activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione S-transferase (GST) and glutathione reductase (GR) in viscera were significantly decreased with dietary menadione. However, activities of these enzymes except for GPX in muscle were increased. Therefore, antioxidant responses of abalone were increased in muscle and decreased in viscera by dietary menadione.

Mercury (Hg^(2+)) effect on enzyme activities and hepatopancreas histostructures of juvenile Chinese mitten crab Eriocheir sinensis

We studied the effects of mercury (Hg2+) on antioxidant and digestive enzyme activities in terms of LC50 value and on hepatopancreas histostructures of juvenile Chinese mitten crabs Eriocheir sinensis in 40-day exposure to various concentrations of Hg2+ (0, 0.01, 0.05, 0.10, 0.20, and 0.30 mg/L). The results show that the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) significantly increased in the concentrations of 0.01 and 0.05 mg/L, while that of enzyme decreased in 0.10, 0.20 and 0.30 mg/L treatments. Meanwhile, Hg2+ disrupted the histostructures of the hepatopancreas, causing decreases in activities of pepsin, tryptase, amylase, and cellulose, which are synthesized in the hepatopancreas. Moreover, as the Hg2+ concentration increased, the survival rate of the crabs decreased, worst at 56.57% in 0.30 mg/L. Therefore, although crabs are able to tolerate low levels of mercury pollution, high levels lead to cellular injury and tissue damage in hepatopancreas, which then loses some of its vital physiological functions such as absorption, storage, and secretion.

Role of PGC-1αin muscle function and aging

This article focuses on the current underlying of molecular mechanisms of the peroxisome proliferator-activated receptor-γ coactivator-1α （PGC-1α） mediated pathway and discuss possible therapeutic benefits of increased mitochondrial biogenesis in compensating for mitochondrial dysfunction and ameliorating aging and aging-related diseases. PGC-1α is the master transcription regulator that stimulates mitochondrial biogenesis, by upregulating nuclear respiratory factors and mitochondrial transcription factor A, leading to increased mitochondrial DNA replication and gene transcription. PGC-1α also regulates cellular oxidant-antioxidant homeostasis by stimulating the gene expression of superoxide dismutase-2, catalase, glutathione peroxidase 1, and uncoupling protein. Recent reports from muscle-specific PGC-1α overexpression underline the benefit of PGC-1α in muscle atrophy and sarcopenia, during which PGC-1α enhanced mitochondrial biogenic pathway and reduced oxidative damage. Thus, PGC-1α seems to have a protective role against aging associated skeletal muscle deterioration.

Growth and antioxidant status of oriental river prawn Macrobrachium nipponense fed with diets containing vitamin E

A feeding trial was carried out to investigate the dietary vitamin E requirement of the oriental river prawn Macrobrachium nipponense(weight of 0.3–0.4 g) and its effect role on antioxidant activity.Prawns were fed with seven levels of vitamin E(0,25,50,75,100,200,and 400 mg/kg diet) for 60 days.The results show that dietary vitamin E supplementation could significantly increased the prawn weight( P <0.05).The activity of superoxide dismutase(SOD) in the hepatopancreas was significantly higher in prawns fed with diets supplemented with ≤75 mg/kg vitamin E than in those fed with diets supplemented with 100–400 mg/kg vitamin E( P <0.05).The activity of catalase(CAT) in the hepatopancreas decreased significantly as dietary vitamin E supplementation increased( P <0.05),and no significant difference was detected in glutathione peroxidase(GSH-Px) activity between different dietary groups( P >0.05).The contents of vitamin E in the hepatopancreas and in the muscle increased with increasing dietary vitamin E.There was a linear correlation between the vitamin E level in diet and that in muscle,and between the vitamin E level in diet and that in the hepatopancreas.All the above results indicated that dietary vitamin E can be stored in the hepatopancreas and muscle and lower both the activities of SOD and CAT in the hepatopancreas,suggesting that it is a potential antioxidant in M.nipponense.Broken line analysis conducted on the weight gains of prawns in each diet group showed that the dietary vitamin E requirement for maximum growth is 94.10 mg/kg.

Oxidative stress and hypoxia-induced factor 1α expression in gastric ischemia

AIM:To investigate the relation of reactive oxygen species (ROS) to hypoxia induced factor 1α (HIF-1α) in gastric ischemia. METHODS:The animal model of gastric ischemia reperfusion was established by placing an elastic rubber band on the proximal part of the bilateral lower limb for ligature for 3 h and reperfusion for 0,1,3,6,12 or 24 h. Ischemic post-conditioning,three cycles of 30-s reperfusion and 30-s femoral aortic reocclusion were conducted before reperfusion. Histological and immunohistochemical methods were used to assess the gastric oxidative damage and the expression of HIF1-α in gastric ischemia. The malondialdehyde (MDA) content and superoxide dismutase (SOD),xanthine oxidase (XOD) and myeloperoxidase (MPO) activities were determined by colorimetric assays. RESULTS:Ischemic post-conditioning can reduce post-ischemic oxidative stress and the expression of HIF-1α of gastric tissue resulting from limb ischemia reperfusion injury. MDA,SOD,XOD and MPO were regarded as indexes for mucosal injuries from ROS,and ROS was found to affect the expression of HIF-1α under gastric ischemic conditions. CONCLUSION:ROS affects HIF-1α expression under gastric ischemic conditions induced by limb ischemia reperfusion injury. Therefore,ROS can regulate HIF-1α expression in gastric ischemia.

Effects of penehyclidine hydrochloride in small intestinal damage caused by limb ischemia-reperfusion

AIM:To investigate the protective effect of penehyclidine hydrochloride post-conditioning in the damage to the barrier function of the small intestinal mucosa caused by limb ischemia-reperfusion(LIR) injury. METHODS:Male Wistar rats were randomly divided into three groups(36 rats each) :the sham-operation group(group S) ,lower limb ischemia-reperfusion group(group LIR) ,and penehyclidine hydrochloride postconditioning group(group PHC) .Each group was divided into subgroups(n=6 in each group) according to ischemic-reperfusion time,i.e.immediately 0 h(T1) ,1 h(T2) ,3 h(T3) ,6 h(T4) ,12 h(T5) ,and 24 h(T6) .Bilateral hind-limb ischemia was induced by rubber band application proximal to the level of the greater trochanter for 3 h.In group PHC,0.15 mg/kg of penehyclidine hydrochloride was injected into the tail vein immediately after 3 h of bilateral hind-limb ischemia.The designated rats were sacrificed at different time-points of reperfusion;diamine oxidase(DAO) ,superoxide dismutase(SOD) activity,myeloperoxidase(MPO) of small intestinal tissue,plasma endotoxin,DAO,tumor necrosis factor-α(TNF-α) ,and interleukin(IL) -10 in serum were detected in the rats. RESULTS:The pathological changes in the small intestine were observed under light microscope.The levels of MPO,endotoxin,serum DAO,and IL-10 at T1-T6,and TNF-αlevel at T1-T4 increased in groups LIR and PHC(P<0.05) compared with those in group S,but tissue DAO and SOD activity at T1-T6 decreased(P<0.05) .In group PHC,the tissue DAO and SOD activity at T2-T6,and IL-10 at T2-T5 increased to higher levels than those in group LIR(P<0.05) ;however,the levels of MPO,endotoxin,and DAO in the blood at T2-T6,and TNF-αat T2 and T4 decreased(P<0.05) . CONCLUSION:Penehyclidine hydrochloride post-conditioning may reduce the permeability of the small intestines after LIR.Its protection mechanisms may be related to inhibiting oxygen free radicals and inflammatory cytokines for organ damage.

Effect of cadmium on the defense response of Pacific oyster Crassostrea gigas to Listonella anguillarum challenge

Heavy metal pollution can affect the immune capability of organisms. We evaluated the effect of cadmium （Cd） on the defense responses of the Pacific oyster Crassostrea gigas to Listonella anguillarum challenge. The activities of several important defensive enzymes, including superoxide dismutase （SOD）, glutathione peroxidase （GPx）, acid phosphatase （ACP）, Na＋, K＋-ATPase in gills and hepatopancreas, and phenoloxidase-like （POL） enzyme in hemolymph were assayed. In addition, the expression levels of several genes, including heat shock protein 90 （IrtSP9~））, metallothionein （MT）, and bactericidal/permeability increasing （BPI） protein were quantified by fluorescent quantitative PCR. The enzyme activities of SOD, ACP, POL, and GPx in hepatopancreas, and the expression of HSP90 were down-regulated, whereas GPx activity in the gill, Na＋, K＋-ATPase activities in both tissues, and MT expression was increased in Cd- exposed oysters post L. anguillarum challenge. However, BPI expression was not significantly altered by co-stress of L. anguillarum infection and cadmium exposure. Our results suggest that cadmium exposure alters the oysters＇ immune responses and energy metabolism following vibrio infection.

Studies on the Effects on Growth and Antioxidant Responses of Two Marine Microalgal Species to Uniconazole

Uniconazole, as a plant growth retardant, can enhance stress tolerance in plants, possibly because of improved antioxidation defense mechanisms with higher activities of superoxide dismutase(SOD) and peroxidase(POD) enzymes that retard lipid peroxidation and membrane deterioration. These years much attention has been focused on the responses of antioxidant system in plants to uniconazole stress, but such studies on aquatic organism are very few. Moreover, no information is available on growth and antioxidant response in marine microalgae to uniconazole. In this paper, the growth and antioxidant responses of two marine microalgal species, Platymonas helgolandica and Pavlova viridis, at six uniconazole concentrations(0-15 mg L-1) were investigated. The results demonstrated that 3 mg L-1 uniconazole could increase significantly chlorophyll a and carbohydrate contents of P. helgolandica(P < 0.05). Higher concentrations(≥12 mg L-1) of uniconazole could inhibit significantly the growth, dry weight, chlorophyll-a and carbohydrate contents of P. helgolandica and P. viridis(P < 0.05). Uniconazole caused a significant increase in lipid peroxidation production(MDA) at higher concentrations(≥ 9 mg L-1). The activities of antioxidant enzymes, superoxide dismutase(SOD) and catalase(CAT) were enhanced remarkably at low concentrations of uniconazole. However, significant reduction of SOD and CAT activities was observed at higher concentrations of uniconazole.

Determination of the Antioxidant Capacity of Different Types of Bread and Flour Using a Superoxide Dismutase Biosensor

The aim was to experimentally evaluate the antioxidant capacity of different types of bread and of the relative flour used for bread production utilizing a superoxide dismutase （SOD） biosensor recently developed by the present authors. Measurements were carried out by comparing the biosensor response to the concentration of superoxide radical produced in solution using a xanthine/xanthine oxidase system in the presence and in the absence of the antioxidant sample considered, respectively. Precision of antioxidant capacity measures for crust and crumb of the different breads was found to be good （RS D% ≤ 8%） and acceptable for the watery suspension and filtrate of the different flours studied （RSD% ≤ 12%）. The obtained results indicated that general flours show higher antioxidant capacity values than the corresponding breads and that crusts show always an antioxidant capacity definitely larger than the crumb. Lastly, the antioxidant capacity values were compared with those of almond, red pepper and strawberry, three foods containing powerful natural antioxidants.

N-acetylcysteine attenuates alcohol-induced oxidative stess in rats

AIM:To investigate free-radical scavenger effect of n- acetylcysteine in rats intragastrically fed with ethanol. METHODS:Twenty-four rats divided into three groups were fed with ethanol (6 g/kg/day,Group 1),ethanol and n- acetylcysteine (1 g/kg,Group 2),or isocaloric dextrose (control group,Group 3) for 4 weeks.Then animals were sacrificed under ether anesthesia,and intracardiac blood and liver tissues were obtained.Measurements were made in both serum and homogenized liver tissues. Malondialdehyde (MDA) level was measured by TBARS method.Glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) levels were studied by commercial kits. Kruskal-Wallis test was used for statistical analysis. RESULTS:ALT and AST in Group 1 (154 U/L and 302 U/L, respectively) were higher than those in Group 2 (94 U/L and 155 U/L) and Group 3 (99 U/L and 168 U/L) (P=0.001 for both).Serum and tissue levels of MDA in Group 1 (1.84 nmol/mL and 96 nmol/100 mg-protein) were higher than that in Group 2 (0.91 nmol/mL and 64 nmol/100 mg protein) and Group 3 (0.94 nmol/ml and 49 nmol/100 mg-protein) (P<0.001 for both).On the other hand,serum GSH-Px level in Group 1 (8.21 U/g Hb) was lower than that in Group 2 (16 U/g Hb) and Group 3 (16 U/g-Hb) (P<0.001).Serum and liver tissue levels of SOD in Group 1 (11 U/mL and 26 U/100 rag-protein) were lower than that in Group 2 (18 U/ mL and 60 U/100 mg protein) and Group 3 (20 U/mL and 60 U/100 rag-protein) (P<0.001 for both). CONCLUSION:Ethanol-induced liver damage was associated with oxidative stress,and co-administration of n-acetylolsteine attenuates this damage effectively in rat model.

Contribution of Antioxidative Enzymes and Anoxia Responsive Genes to Submergence Tolerance in Rice: A Review

Flooding/submergence of rice fields is a severe problem in South and South-East Asia, affecting more than 20 million hectares of rice every year. Submergence creates hypoxic or anoxic condition causing poor germination, seedling establishment,and enormous yield loss. Standing water in the field from weeks to months also leads to significant yield losses when large part of aerial tissues is under water. For flash flooding, a rice variety FR1A3 with tolerant gene(SUB1A) was identified. SNORKEL1 and SNORKEL2 have been identified for their ability to survive deep-water flooding by rapid elongation. Submergence stress has also been reported to adversely affect cell division and damage cellular and organelle membranes. Research on antioxidative enzymes response and genes that confer tolerance to prolonged flooding is in progress. Here we review the different anoxia responsive genes and the potential involvement of antioxidative enzymes, such as superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase, which occur in cells of rice plant exposed to submergence stress.

Antioxidative capacity and enzyme activity in Haematococcus pluvialis cells exposed to superoxide free radicals

The antioxidative capacity of astaxanthin and enzyme activity of reactive oxygen eliminating enzymes such as superoxide dismutase (SOD),peroxidase (POD),catalase (CAT) and ascorbate peroxidase (APX) were studied in three cell types of Haematococcus pluvialis exposed to high concentrations of a superoxide anion radical (O2ˉ).The results show that defensive enzymes and astaxanthin-related mechanisms were both active in H.pluvialis during exposure to reactive oxygen species (ROS) such as Oˉ2.Astaxanthin reacted with ROS much faster than did the protective enzymes,and had the strongest antioxidative capacity to protect against lipid peroxidation.The defensive mechanisms varied significantly between the three cell types and were related to the level of astaxanthin that had accumulated in those cells.Astaxanthin-enriched red cells had the strongest antioxidative capacity,followed by brown cells,and astaxanthin-deficient green cells.Although there was no significant increase in expression of protective enzymes,the malondialdehyde (MDA) content in red cells was sustained at a low level because of the antioxidative effect of astaxanthin,which quenched Oˉ2 before the protective enzymes could act.In green cells,astaxanthin is very low or absent;therefore,scavenging of ROS is inevitably reliant on antioxidative enzymes.Accordingly,in green cells,these enzymes play the leading role in scavenging ROS,and the expression of these enzymes is rapidly increased to reduce excessive ROS.However,because ROS were constantly increased in this study,the enhance enzyme activity in the green cells was not able to repair the ROS damage,leading to elevated MDA content.Of the four defensive enzymes measured in astaxanthin-deficient green cells,SOD eliminates Oˉ2,POD eliminates H2O2,which is a by-product of SOD activity,and APX and CAT are then initiated to scavenge excessive ROS.

Predictive biomarker and clinicopathological characteristics analysis for esophageal cancer

Objective:The aim of this study was to explore the expression of manganese superoxide dismutase(MnSOD) in esophageal squamous cell carcinoma and its relationship with clinicopathological characteristics and its biological behavior.Methods:Immunohistochemical method(SP method),reverse transcription-polymerase chain reaction(RT-PCR) and Western blot were combined to detect the MnSOD protein and mRNA expression in 45 cases of esophageal squamous cell carcinoma and the normal tissue that was 5 cm apart from the edge of esophageal cancer lesion and without documented microscopic invasive cancer.Meanwhile,analysis was performed on the relationship between the pathological features of esophageal cancer and its biological behavior.Results:In esophageal squamous cell carcinoma and normal esophageal tissue,MnSOD protein expression was identified in 31.1%(14/45) and 86.7%(31/45)(P = 0.003),respectively,with the relative expression levels of MnSOD mRNA were 0.310 ± 0.036 and 0.482 ± 0.053(P = 0.000).The longer the lesions and the deeper the invasion,the differentiation would become poorer and the expression level of MnSOD would get lower,indicating that the level of MnSOD protein and mRNA expression were closely related to esophageal squamous cell carcinoma in the length of lesion,depth of invasion,and degree of differentiation(P < 0.05).Nevertheless,it showed no association with the presence of the lymph node metastasis,lesion site and the macroscopic classification(P > 0.05).Conclusion:The MnSOD protein and mRNA expression were both decreased in esophageal squamous cell carcinoma tissue.This may be related to the carcinogenesis and development of esophageal cancer.Detection of the expression of MnSOD would be of clinical significance in understanding the prognosis and guiding therapeutic strategy of esophageal cancer.