Effects of Ethyl Pyruvate on Myocardial Apoptosis and Expression of Bcl-2 and Bax Proteins after Ischemia-reperfusion in Rats

In order to study the effects of ethyl pyruvate on cardiomyocyte apoptosis following ischemia/reperfusion （I/R） in vitro and the expression of Bcl-2 and Bax proteins, isolated rat hearts were perfused in a Langendorff model. Twenty-four rats were randomly divided into 3 groups （n=8 in each group）： control group was perfused for 120 min. In the I/R group, after 30 min stabilization the injury was induced by 30 min global ischemia followed by 60 min reperfusion. Ethyl pyruvate （EP） group was set up with the same protocol as I/R group except that it was supplied with 2 mmol/L EP 15 rain before ischemia and throughout reperfusion. Myocardial malonaldehyde （MDA） content was measured. Myocardial apoptotic index （AI） was tested by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling （TUNEL） method. The expression of anti-apoptotic protein Bcl-2 and pro-apoptotic protein Bax in cardiac myocytes was detected by immunohistochemistry. As compared with control group, the content of MDA, myocardial AI and the expression of Bcl-2, Bax proteins were increased significantly in I/R group, but the content of MDA, myocardial AI and the expression of Bax protein were decreased obviously and the expression of Bcl-2 protein was up-regulated in EP group （P〈0.05）. These results demonstrate that EP could inhibit apoptosis of cardiac myocytes possibly via alleviating oxidative stress, up-regulating Bcl-2 and down-regulating Bax proteins.

Pretreatment with low-frequency repetitive transcranial magnetic stimulation may influence neuronal Bcl-2 and Fas protein expression in the CA1 region of the hippocampus: A possible anti-epilepsy mechanism in a lithium-pilocarpine-induced epileptic rat mod

BAOKGROUND： Bcl-2 and Fas proteins are well known as anti-apoptotic and pro-apoptotic factors respectively. However, whether the anti-epileptic mechanism of low-frequency repetitive transcranial magnetic stimulation （rTMS） involves an anti-apoptotic effect via regulating Bcl-2 and Fas protein expression remains to be determined. OBJECTIVE： To verify the correlation between the anti-epileptic mechanism following pretreatment of low-frequency rTMS and anti-hippocampal apoptosis. DESIGN, TIME AND SETTING： A randomized controlled animal experiment was performed at Institute of Neurological Disorders, Affiliated Hospital of North Sichuan Medical College between September 2007 and March 2008. MATERIALS： Pilocarpine （053K13011） was provided by Sigma, USA; lithium was provided by Shanghai Biotechnology Co., Ltd., China; Dantec Maglite-r25 rTMS instrument was provided by Dundee, Denmark. METHODS： A total of 21 adult male Wistar rats were randomly divided into control （n = 6）, rTMS pretreatment （n = 9）, and sham-stimulation （n = 6） groups. The rTMS pretreatment group was pretreated with low-frequency rTMS （0.5 Hz, 75% threshold intensity, 20 times/bundle, and 5 bundles/day）, while the sham-stimulation group was sham-stimulated with a similar sound for 7 successive days to establish lithium-pilocarpine-induced epileptic state models. MAIN OUTCOME MEASURES： Epileptic stroke latency; neuronal morphology was observed using hematoxylin and eosin staining; mean positive-reactive cell number and mean absorbance of Bcl-2 and Fas protein in the hippocampal CA1 region was observed using immunohistochemistry. RESULTS： Epileptic latency in the rTMS pretreatment group was significantly enhanced （P 〈 0.01）, and a number of degenerated neurons were observed to be apoptotic. Bcl-2 protein expression increased at each time point, but Fas protein expression decreased （P 〈 0.01）. CONCLUSION： Low-frequency rTMS has an anti-epileptic effect, which may be via regulation of Bcl-2 and Fas protein expression in the hippocampal region.

Expression of bcl-2 protein in gastric carcinoma and its significance

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Function of apoptosis and expression of the proteins Bcl-2,p53 and C-myc in the development of gastric cancer

INTRODUCTIONIn China ,the incidence and mortality of gastric cancer rank the second among all cancers. Recent development of cancer [1-20].The aim of this study was investigat the insight of apoptosis and bcl-2, p53 and C-myc protein expression in the development of gastric cancer .

Dioscin-induced Apoptosis of Human LNCaP Prostate Carcinoma Cells through Activation of Caspase-3 and Modulation of Bcl-2 Protein Family

Dioscin is a natural steroid saponin derived from several plants, showing potent anti-cancer effect against a variety of tumor cell lines. In the present study, we investigated the anti-cancer activity of dioscin against human LNCaP cells, and evaluated the possible mechanism involved in its antineoplastic action. It was found that dioscin（1, 2 and 4 μmol/L） could significantly inhibit the viability of LNCaP cells in a time- and concentration-dependent manner. Flow cytometry revealed that the apoptosis rate was increased after treatment of LNCaP cells with dioscin for 24 h, indicating that apoptosis was an important mechanism by which dioscin inhibited cancer. Western blotting was employed to detect the expression of caspase-3, Bcl-2 and Bax in LNCaP cells. The expression of cleaved caspase-3 was significantly increased, and meanwhile procaspase-3 was markedly decreased. The expression of anti-apoptotic protein Bcl-2 was down-regulated, whereas the pro-apoptotic protein Bax was up-regulated. Moreover, the Bcl-2/Bax ratio was drastically decreased. These results suggested that dioscin possessed potential anti-tumor activity in human LNCaP cells through the apoptosis pathway, which might be associated with caspase-3 and Bcl-2 protein family.

Presence of Fas and Bcl-2 proteins in BEL-7404 human hepatoma cells

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THE EXPERIMENTAL STUDY ON THE CELL APOPTOSIS AND EXPRESSION OF BCL-2 PROTEIN IN INTRACEREBRAL HEMORRHAGE IN MODEL OF RATS

Objective To study whether there is the apoptosis of neural cells and the expression of Bcl-2 protein in intracerebral hemorrhage (ICH) in model of rats, for the further understanding the mechanism of the delayed damage of the neural cells around the hematoma after ICH. Methods Fifty SD rats were randomly divided into 5 groups, ten in each. With the Group A as the control, the rest 40 were used to set up intracerebral hemorrhage model. The brains were taken out at 12 th , 24 th , 48 th and 72 th hours, respectively. Apoptosis cells were detected with terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL), and the expression of Bcl-2 protein was detected with immunochemical stainging methed (SP). Results In the control group, no apoptosis cells and Bc1-2 protein were detected. In rest groups, the apoptosis cells and Bc1-2 protein were expressed in different degree. Apoptosis rates verified and corresponded with the time after ICH, with the peak at 48 th -72 th hour after hemorrhage. The peak rate of apoptosis cells was (24.50±2.69)% and Bcl-2 protein expression was (20.76±1.97)% . There was significant difference between the experimental groups and control (P<0.05), and no linear relationship between the apoptosis rate and the expression of Bcl-2 protein. Conclusion Apoptosis may be an important factor in the secondary trauma of ICH. There is a time leg after hemorrhage. All this is instructive to clinical treatment in time. Bcl-2 protein keeps increasing in a certain time after hemorrhage, but not synchronize with the cell apoptosis. This indicates that bcl-2 has the effect to reduce the apoptosis of neural cells.

THE QUANTITATIVE MEASUREMENT OF BCL-2, P53 PROTEIN AND PCNA EXPRESSION IN BREAST CARCINOMA AND THEIR CORRELATION WITH PROGNOSIS

To study quantitative index of bci-2, P53, Nroliferating cell nuclear antigen (PCNA),ER and PR in breast carcinoma and their correiation and their relatiousbip with prognosis, the ex expression of bcl-2, P53 and PCNA were studied by immunohistochemical technique. The measurementof ER and PR used enzyme linked affinuity histochemical methods. The quantitative index was analyzed by image technique. All analyses were hased on 60 breast carcinomas. The results were as follows:the more bcl-2 protein, the lower histological graded the longer survival term and the highersurvival rate (P< 0. 05). The quautitative measurement of bcl-2, P53 and PCNA expression were ofvalue in evaluating the degree of differentiation and prognosis in breast carcinoma. The quantitativeand qualitative measurement or p53 protein expression showed a Ⅰwerful evidence in evaluatingprognosis of bcl-2 were more significant in evaluating poor prognosis of breast carcinoma. A relationship between bcl-2 and ER, PR showed a better value for response to endocrine therapy in breastcarcinoma patients.

Regulatory Effect of Bcl-2 Family Proteins in CPB-induced Cardiomyocyte Apoptosis in Dog Hearts

Summary: Whether conventional hypothermic CPB induces myocyte apoptosis in dog hearts and modulation of bcl-2, bcl-xl, bax, bad, and caspase-3 pathways in this setting was investigated. Ten healthy adult dogs were randomized into sham-operated and CPB groups. Samples of left ventricle were obtained before, during and 3 h after CPB. In situ TUNEL was used to detect apoptotic myocytes. Immunohistochemistry and flow cytometry were employed for detection of expressions of bcl-2, bcl-xl, bax and bad proteins. Z-DEVD-AMC substrate cleavage and TBARS methods were used to measure the activity of caspase-3 and the content of lipid peroxide in LV myocardium, respectively. After CPB, the number of apoptotic myocytes in CPB group was significantly increased. The results of immunohistichemistry demonstrated that bcl-2, bcl-xl, bax and bad proteins were constitutionally present on the sarcolemma of the LV myocytes. FACS results showed that, after CPB, expressions of bax and bad in CPB group were significantly upregulated, while the expressions of bcl-2 and bcl-xl were not significantly changed in both groups. The activity of caspase-3 and the content of lipid peroxide in LV myocardium in CPB group were also significantly increased after CPB. The present study shows that there exists myocardiocyte apoptosis in dog hearts undergoing conventional hypothermic CPB and the myocyte apoptosis is initiated by ischemia and performed during reperfusion. Moreover, the CPB-induced myocyte apoptosis was associated with upregulation of expressions of bax and bad proteins, activation of caspase-3 and increase of oxidative stress.

Melatonin restores normal Bax and Bcl-2 protein expression in the subgranular zone of the dentate gyrus in pinealectomized rats

In this study, we sought to elucidate the effects of melatonin on learning and memory as well as apoptosis and expression of the Bax or Bcl-2 proteins in the subgranular zone of the dentate gyrus in pinealectomized rats. Using the Morris water maze and the olfactory memory tests, we found that the average escape latency in pinealectomized rats was clearly increased compared with sham-operated rats. Moreover, the average escape latency in the melatonin-treated and pinealectomized rats was longer than that in the sham-operated rats and shorter than that in the pinealectomized and untreated rats. Immunohistochemistry and terminal-deoxynucleoitidyl transferase mediated nick end labeling （TUNEL） showed that there were fewer Bax immunoreactive cells and TUNEL-positive （apoptotic） cells but more Bcl-2 immunoreactive cells in the melatonin-treated rats compared with the pinealectomized rats. The sham-operated rats showed numbers of these cells similar to the melatonin-treated rats. These experimental findings demonstrate that melatonin treatment may reduce abnormal apoptosis by promoting gene expression of Bax and suppressing gene expression of Bcl-2 in the subgranular zone of the dentate gyrus in pinealectomized rats. These effects appear to result in the inhibition of cellular apoptosis and the improvement of spatial learning and memory in pinealectomized rats.

Signal transduction mediated by Bid,a pro-death Bcl-2 family proteins, connects the death receptor and mitochondria apoptosis pathways

Two major apoptosis pathways have been defined in mammalian cells, the Fas/TNF-R1 death receptor pathway and the mitochondria pathway. The Bcl-2 family proteins consist of both anti-apoptosis and pro- apoptosis members that regulate apoptosis, mainly by controlling the release of cytochrome c and other mitochondrial apoptotic events. However, death signals mediated by Fas/TNF-R1 receptors can usually activate caspases directly, bypassing the need for mitochondria and escaping the regulation by Bcl-2 family proteins. Bid is a novel pro-apoptosis Bcl-2 family protein that is activated by caspase 8 in response to Fas/TNF-R1 death receptor signals. Activated Bid is translocated to mitochondria and induces cytochrome c release, which in turn activates downstream caspases. Such a connection between the two apoptosis pathways could be important for induction of apoptosis in certain types of cells and responsible for the pathogenesis of a number of human diseases.

How the Bcl-2 family of proteins interact to regulate apoptosis

到 apoptosis 的房间的承诺主要被在 Bcl-2 蛋白质家庭的成员之间的蛋白质蛋白质相互作用管理。它的三个亚科有不同角色：BH3 仅仅，蛋白质经由他们的 BH3 领域由绑定触发 apoptosis 到支持幸存的亲戚，当 pro-apoptotic Bax 和 Bak 有一个必要下游的角色包含 organellar 膜和 caspase 激活的正式就职的混乱时。BH3 仅仅，蛋白质充当损坏传感器，由压力信号保持惰性直到他们的激活。一旦激活，他们被认为杂乱地绑在支持幸存的蛋白质目标，但是意外选择最近从他们的相互作用的分析出现了。BH3 仅仅，蛋白质也绑在 Bax 和 Bak 的一些。Bax 和 Bak 是否被这些 BH3 仅仅直接激活蛋白质，或间接地作为后果 BH3 仅仅蛋白质抵销他们的支持幸存的目标是强烈争论的题目。不管这，在家庭成员之间的相互作用的详细理解，经常选择，为设计反癌症药指向 Bcl-2 家庭有著名含意。

Clinicopathological significance of Bcl-2 and Bax protein expression in human pancreatic cancer

AIM: To assess the clinicopathological significance of the expression of the apoptosis-inhibitory Bcl-2 protein (pBcl-2) and the apoptosis-promoting Bax protein (pBax) in human invasive ductal carcinomas (IDCs) of the pancreas. METHODS: Fifty-nine surgical specimens of IDCs of the pancreas were stained immunohistochemically to detectpBcl-2 and pBax expressions whose correlation to tumor classification, staging, and prognosis was analyzed by univariate and multivariate analyses. RESULTS: The expression of pBcl-2 and pBax was detected in 21 of 59 (35.6%) and in 29 of 59 (49.2%) patients with IDCs of the pancreas, respectively. Neither pBcl-2 nor pBax alone was correlated to TNM staging and differentiation degree of IDCs of the pancreas according to univariate analysis. By Mantel-Cox test, the median survival time after surgery for pBcl-2(+) and pBcl-2(-) groups were 14.3 and 7.3 mo, respectively (χ2= 9.357, P = 0.002) and that for pBax(+) and pBax(-) groups were 12.9 and 10.2 mo, respectively (χ2= 0.285, P＞0.05).Contingency coefficient between pBd-2 and pBax expression was 0.298, indicating that there was correlation between them (χ2= 5.74, P＜0.05). The median survival time after surgery for pBd-2(+)pBax(+) and pBcl-2(+)pBax(-) groups were 14.3 and 14.1 mo, respectively, and that for pBcl-2 (-)pBax(+) and pBcl-2(-)pBax(-) groups were 5.9 and 9.9 mo, respectively. There was a significant difference between pBcl-2(+)pBax(+) and pBcl-2(-)pBax(+) (χ2 = 5.06,P＜0.05), such was the case for pBcl-2(+)pBax(+) andpBcl-2(-)pBax(-) (χ2= 7.18, P＜0.01). Cox proportional hazards model for multivariate analysis was applied, indicating that pBcl-2, TNM staging, age and pBax were high risk factors of post-surgical survival time. CONCLUSION: Both pBcl-2 and pBax have high expression in IDCs of the pancreas, indicating that co-expression of pBcl-2 and pBax is a good indicator of favorable prognosis in IDCs of the pancreas.

High expression of anti-apoptotic protein Bcl-2 is a good prognostic factor in colorectal cancer: Result of a metaanalysis

AIM To systematically evaluate the prognostic-predictive capability of Bcl-2 in colorectal cancer(CRC).METHODS A systematic literature search was conducted using Pub Med,Web of Science and EMBASE databases. Any eligible study must meet the following criteria:(1) bcl-2 expression was evaluated in human CRC tissues by immunohistochemistry;(2) assessment of the relationships between bcl-2 expression and overall survival(OS),disease free survival(DFS),recurrent free survival(RFS) or clinic-pathological characteristics of CRC was included;(3) sufficient information was provided to estimate the hazard ratio(HR) or odds ratio and their 95% confidence intervals(CIs); and(4) the study was published in English. The impact of Bcl-2 expression on survival of CRC patients were evaluated through this meta-analysis.RESULTS A total of 40 eligible articles involving 7658 patients were enrolled in our final analysis. We drew the conclusion that Bcl-2 high expression was significantly correlated with favorable OS(pooled HR = 0.69,95%CI: 0.55-0.87,P = 0.002) and better DFS/RFS(pooled HR = 0.65,95%CI: 0.50-0.85,P = 0.001). Additionally,the subgroup analysis suggested that Bcl-2 overexpression was significantly associated withprognosis(OS) especially in patients came from Europe and America but not Asian and patients who did not receive any adjuvant therapy before surgery. Finally,our present results indicated that expression of bcl-2 protein was associated with high differentiation grade and A/B Ducks' stage. CONCLUSION Bcl-2 high expression was significantly correlated with favorable OS and better DFS/RFS. Hence,we propose that Bcl-2 may be a valuable prognostic-predictive marker in CRC.

Effects of genistein on neuronal apoptosis,and expression of Bcl-2 and Bax proteins in the hippocampus of ovariectomized rats

Genistein is one of several isoflavones that has a structure similar to 17β-estradiol, has a strong antioxidant effect, and a high affinity to estrogen receptors. At 15 weeks after ovariectomy, the expression of Bcl-2 in the hippocampus of rats decreased and Bax expression increased, with an obvious upregulation of apoptosis. However, intraperitoneal injection of genistein or 17β-estradiol for 15 consecutive weeks from the second day after operation upregulated Bcl-2 protein expression downregulated Bax protein expression, and attenuated hippocampal neuron apoptosis. Our experimental findings indicate that long-term intervention with genistein can lead to a decrease in apoptosis in hippocampal neurons following ovadectomy, upregulate the expression of Bcl-2, and downregulate the expression of Bax. In addition, genistein and 17β-estradiol play equal anti-apoptotic and neuroprotective roles.

Effect of compound preparation Tongqiao Jiannao capsules on neural cell apoptosis and Bcl-2 and Bax protein levels in a rat model of brain ischemia/reperfusion injury

BACKGROUND：Pharmacological studies have demonstrated that compound preparation Tongqiao Jiannao capsules composed of Zexie, Baizhu, Honghua, Danshen, and Shexiang can supplement qi, activate blood circulation, relieve blood stasis, induce resuscitation for alleviating pain, relieve pain, and dilate blood vessels. OBJECTIVE： To observe the effects of Tongqiao Jiannao capsules on the levels of the anti-apoptotic protein Bcl-2 and the proapoptotic protein Bax, and verify the mechanism of action. DESIGN, TIME AND SETTING： Randomized, controlled animal experiment, performed in the Laboratory of Biochemistry and Molecular Biology, Shanxi Medical University between June 2001 and December 2002. MATERIALS： The right middle cerebral arteries of 24 healthy adult Sprague Dawley rats were occluded by the suture method. The primary Chinese herbal medicinal ingredients of Tongqiao Jiannao capsules are Zexie, Baizhu, Honghua, Danshen, and Shexiang, which were purchased from Shanxi Provincial Medicinal Material Company, China, and prepared into condensed granules in the Room for Chinese Herbal Medicine Preparation, Second Hospital, Shanxi Medical University. Bcl-2 and Bax immunohistochemical staining kits, a 3,3-diaminobenzidine（DAB） kit, and an in situ apoptosis detection kit were purchased from Wuhan Boster Bioengineering Co., Ltd., China. METHODS： Twenty-four rats were randomly and evenly divided into three groups： （1） sham-operated rats in which sutures were inserted and immediately pulled out; （2） Tongqiao Jiannao capsule-treated rats that were intragastrically administered 6.5 g/kg/d Tongqiao Jiannao capsule preparation for seven successive days prior to middle cerebral artery occlusion （MCAO）; and （3） MCAO rats without any other treatments. MAIN OUTCOME MEASURES： The levels of neural cell apoptosis and Bcl-2 and Bax proteins at 24 hours post-surgery. RESULTS： In the MCAO group, the numbers of apoptotic cells and Bax-positive cells were significantly increased, while the numbers of Bcl-2-positive cells were slightly decreased compared with the sham-operated group. Bcl-2- and Bax-positive cells and apoptotic cells were primarily distributed in the ischemic penumbra. In the Tongqiao Jiannao capsule-treated group, neuronal apoptosis was inhibited, and the number of Bcl-2-positive cells was significantly increased （P 〈 0.01）, while the number of Bax-positive cells was significantly decreased （P 〈 0.01）, compared with the MCAO group. CONCLUSION： Tongqiao Jiannao capsules elevated Bcl-2 expression, lowered Bax expression, and inhibited cellular apoptosis during the process of cerebral ischemia/reperfusion injury.

Effects of Local Testicular Heating on Bcl-2 and Bax Protein Expression in Spermatogenic Cells in Rats

Objective To investigate the expression of Bcl-2 and Bax in spermatogenic cells induced by local testicular heating in rats Methods Forty adult male SD rats were divided into experimental group and control group at random. According to day 0.5, 1, 3 and 6 after local testicular heating, each group was divided into 4 subgroups： experimental subgroup （n=6） and control subgroup （n=4）. The expression of Bcl-2 and Bax in the spermatogenic cells was detected on day 0.5, 1, 3 and 6 after heat exposure by using immunohistochemistry. Results Compared with control groups, the ratio of positive cells and content of Bcl-2 positive cells significantly decreased in all experimental subgroups （P〈0.01）. The content of Bax positive cells increased in all experimental subgroups （P〈0.01）, the ratio of positive cells which had no significant difference （P〉0.05） except 6 d group decreased （P〈0.01 ）. Redistribution of Bax from a cytoplasmic to perinuclear or nuclear localization could be observed after heating. Conclusions Expression of Bcl-2 would decrease and Bax would increase with redistribution in spermatogenic cells in rats after heating. The change of Bcl-2 and Bax expression in spermatogenic cells would be correlated with the spermatogenic cell apoptosis induced by heating.

The Protein Expression of Bcl-2, Bax, Fas/Apo-1 in Acute Myeloid Leukemia

The protein expression of bcl-2, bax, Fas/Apo-1 in 19 cases of acute myeloid leukemia (AML) were investigated by Western blot and APAAp techniques. High expression of bcl-2 protein was found in most of the AML cases,and some of the cases expressed Fas/Apo-1 and bax. High expression of bcl-2 protein was associated with a bad clinical prognosis and a poor response after intensive chemotherapy. Bax seemed to coexpress with bcl-2 and so appeared to be a bad prognostic factor instead of a good one. The expression of Fas/Apo-1 was inversely correlated with hcf-2 and seemed to be a good prognostic factor which may reflect the relative homeostasis of apoptotic pathway. It is concluded that apoptosis-induced pathways in AML often exhibit disturbance features. Coregulation of bcl-2, Bax and Fas/Apo-1 genes formed the apoptosis-induced pathway,which is the biological factor affecting response to chemotherapy.

The Effect of Targeted Magnetic Nanopaticles on Hepatoma and the Expression of bcl-2/bax Protein

The effect of targeted magnetic nanoparticles on hepatoma and the underlying mechanism were examined. Nude mice transplanted with a human hepatoma cell line （HepG2 cells） were randomized into 5 groups, including： （1） group A, receiving normal saline, （2） group B, receiving 5-fluorouracil （5-Fu）, （3） group C, receiving magnetic nanoparticles containing 5-Fu, （4） group D, consisting of treatment with magnetic nanoparticles containing 5-Fu and inside magnetic field and （5） group E, receiving pure magnetic nanoparticles and inside magnetic field. Morphological features of transplanted tumors in mice in each group were observed under transmission electron microscope （TEM）. The expression of bcl-2/bax protein was immunohistochemically detected by SABC method. The results showed that a large number of apoptotic tumor cells were found in group B and group D under TEM. The expression of bcl-2 protein was significantly decreased and the expression of bax protein increased significantly in both group B and D as compared with those in group A, C and E （P〈0.01 for all）. The decrease in bcl-2 and the increase in bax were more in group D as compared with group B （P〈0.01）. It is concluded that the targeted magnetic nanoparticles containing 5-Fu can improve the chemotherapeutic effect of 5-Fu by decreasing bcl-2 expression, increasing bax expres- sion and inducing apoptosis of the liver cancer cells.

THE EXPRESSION OF BCL-2 AND BAX PROTEINS IN GASTRIC CARCINOMA AND PRECANCEROUS LESIONS

Objective To investigate the variance of expression of bcl-2 and bax genes in the genesis or gastric carcinoma as well as their relationship. Methods Thirty-five cases of early-stage gastric carcinoma and Twenty-four cases ot chronic atrophic gastritis were studied by immunohistochemical method. Results There were no statistical differences of bcl-2 expression levels between gastric carcinoma and atypical hyperplasia or paracancerous intestinal- epithelial metaplasia(IEM) (P>0.05).There were statistical differences of bcl-2 expression between normal epithe- lial tissues (or non-cancerous IEM) and the other three groups(P<0.05), but no statistical difference between the normal epithelial and the non-cancerous IEM group was observed(P>0.05). The expressions or bax protein were found in the normal epithelial and the other groups in varying degrees,but there were no statistical differences be- tween either two of the groups (P>0.05). The bcl-2/bax ratio was higher in early-stage gastric carcinoma,atypical hy- perplasia and paracancerous intestinal-metaplasia than in the non-cancerous intestinal-metaplasia (P<0.05) and nor- mal epithelial tissues(P<0.01). Conclusion The abnormal expression of bcl-2 protein and bax protein,especially the increased bcl-2/bax ratio, probably play an important role in the course of carcinogenesis or gastric carcinoma.