Expression of Bcl-2 and Bax in the human corpus luteum during the menstrual cycle and in early pregnancy: regulation by human chorionic gonadotropin

To investigate the relationship between apoptosis and the Bcl-2/ Bax system in the human corpus luteum (CL), the frequency of apoptosis and expression of Bcl-2 and Bax were examined in the CL during the menstrual cycle and in early pregnancy. In situ analysis of DNA fragmentation showed that the number of apoptotic cells was much greater in the regressing CL than that in the midluteal phase CL, whereas there were almost no apoptotic cells in the CL of early pregnancy. Immunohistochemistry revealed that Bcl-2 expression was observed in the luteal cells in the midluteal phase and early pregnancy, but not in the regressing CL. In contrast, Bax immunostaining was observed in the regressing CL, but not in the midluteal phase and early pregnancy. bcl-2 messenger ribonucleic acid (mRNA) levels in the CL during the menstrual cycle were highest in the midluteal phase and lowest in the regressing CL. In the CL of early pregnancy, bcl-2 mRNA levels were significantly higher than those in the midluteal phase. In contrast, bax mRNA levels were highest in the regressing CL and remarkably low in the CL of early pregnancy. Western blot analyses revealed that Bcl-2 expression was significantly lower in the regressing CL than in the midluteal phase and early pregnancy, and that Bax expression was, in contrast, significantly higher in the regressing CL than in the midluteal phase and was remarkably low in the CL of early pregnancy. When corpora lutea of the midluteal phase were incubated with hCG, hCG significantly increased the mRNA and protein levels of Bcl-2 and significantly decreased those of Bax. In conclusion, Bcl-2 and Bax may play important roles in the regulation of the life span of the human CL by controlling the rate of apoptosis. hCG may act to prolong the life span of the CL by increasing Bcl-2 expression and decreasing Bax expression when pregnancy occurs.     

Apoptosis and apoptosis-related proteins in human endometrium

Apoptosis has been shown to be an important regulator of endometrium function. To study the regulation of apoptosis in the endometrium during the normal menstrual cycle, the expression of the apoptosis related proteins Bcl-2 and Bax and their correlation to serum estradiol and progesterone, as well as to a replication-related antigen Ki-67 were analyzed. Nine uterine tissue samples and thirty-nine endometrial biopsy specimens were studied. Apoptosis was studied quantitatively by Southern blot analysis of internucleosomal cleavage of genomic DNA, and qualitatively by using in situ 3'-end labeling of fragmented DNA, and Bcl-2, Bax and Ki-67 were detected and quantified immunohistochemically. Apoptotic cells were mostly detected in the glandular epithelium of late secretory and menstruating endometrium. Immunostaining of Ki-67 was detected predominantly in proliferative endometrium. The expression of Bcl-2 was high in proliferative endometrium and decreased in the secretory phase, being very low or absent in the mid- and late secretory and menstruatory phases. Similarly, Bax expression also decreased, but was still present throughout the secretory phase. In human endometrium, apoptosis occurs predominantly in the late secretory and menstrual phases, and is related to alterations in the expression of Bcl-2 and Bax. A decrease in the Bcl-2/Bax ratio in the early secretory phase precedes DNA fragmentation and may predispose the cells to apoptosis.     

Expression of messenger ribonucleic acid species encoding steroidogenic enzymes in human follicles and corpora lutea throughout the menstrual cycle

The levels of expression of mRNA species encoding cholesterol side-chain cleavage cytochrome P-450 (P450scc), 17 alpha-hydroxylase cytochrome P450 (P450(17 alpha], aromatase cytochrome P-450 (P-450AROM), and 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) were examined in human follicles and corpora lutea (CL) throughout the menstrual cycle. Tissues were obtained from women undergoing hysterectomy and oophorectomy. The largest follicle or the CL was dissected from the ovary depending on whether the surgery was performed in the follicular or luteal phase. The day of the cycle was determined by onset of last menstrual period and was confirmed by endometrial histology. Total RNA was examined by Northern blot analysis, using as probes specific 32P-labeled cDNA inserts encoding each human enzyme. Early follicles demonstrated detectable mRNA for both P450scc and P450(17 alpha), but not for P450AROM or 3 beta HSD. P450AROM was detectable late in the follicular phase and appeared markedly induced in the CL. 3 beta HSD was detectable only in the CL. Levels of P450(17 alpha) mRNA remained relatively unchanged throughout the cycle, whereas P450scc mRNA levels were greatly increased in the CL. The presence of P450(17 alpha) mRNA in the human CL is of interest, since it is absent from the bovine CL, and this is consistent with the ability of the human, but not the bovine, CL to synthesize 17 alpha-hydroxyprogesterone and estrogens. The fact that P450AROM expression is highest in CL is surprising, since plasma estrogen levels are highest during the late follicular phase of the cycle, and may suggest that CL estrogen biosynthesis is limited by 17 alpha-hydroxylase or 17,20-lyase activities.     

Expression of apoptosis-regulating proteins p53, Bcl-2, and Bax in primary resected esophageal squamous cell carcinoma

Apoptosis plays a key role in the pathogenesis, aggressiveness, and therapy responsiveness of cancer. Proteins of the Bcl-2 family as well as p53 are important regulators of apoptosis. The present study retrospectively examines the expression of apoptosis-regulating proteins in primary resected esophageal squamous cell carcinoma (ESCC) and the correlation between the outcome of patients' treatment and the expression of the proteins. We used antibodies specific for the human p53, Bcl-2 and Bax proteins to examine the expression of these apoptosis-regulating proteins in 40 archival specimens of patients with primary resected esophageal squamous cell carcinoma. The overall expression of p53, Bcl-2, and Bax was 73%, 18%, and 100%, respectively. No significant correlations were found between the expression of p53, Bcl-2, and Bax. The expression of Bcl-2 had a negative influence on survival in this population of primary resected ESCC patients (p=0.03). But no differences in survival were observed in relation to the expression of p53 or Bax. In conclusion, Bcl-2 expression may provide additional and prognostic information for the clinical course of the disease and therefore to be developed as a prognostic indicator for primary resected esophageal squamous cell carcinoma.     

Bcl-2和Bax在多巴胺诱导PC12细胞凋亡中的作用

目的探讨多巴胺诱导PC12细胞凋亡的可能机制。方法流式细胞仪检测PC12细胞的凋亡率及Bcl-2和Bax蛋白的表达率。结果多巴胺诱导PC12细胞凋亡,两者间呈明显的量效和时效关系。0.45mmol/L多巴胺作用24h,细胞的凋亡率为53.3%±3.1%。在凋亡过程中,Bcl-2蛋白表达显著降低,Bax蛋白表达随之增高。诱导型一氧化氮合成酶(iNOS)抑制剂和半胱氨酸蛋白酶3(CPP32)抑制剂对抗多巴胺诱导PC12细胞的凋亡作用与Bcl-2蛋白增加、Bax蛋白降低有关。结论Bcl-2和Bax蛋白是多巴胺诱导PC12细胞凋亡的重要调节蛋白,iNOS和CPP32在凋亡过程中可能具有重要作用。     

Expression of steroid hormone receptors, proliferation and apoptotic markers in primate endometrium

In humans, circulating levels of steroid hormones vary during the menstrual cycle, with oestrogen elevated in the proliferative phase and progesterone increased during the secretory phase. In humans, oestrogen levels also increased during the mid-secretory phase, but this is not observed in non-human primates. In marmosets, the New World monkeys, plasma oestrogen and progesterone levels exhibit similar profiles as those found in Old World monkeys, however, these animals do not menstruate. Proliferative and apoptotic changes occur at specific phases of the menstrual cycle, suggesting regulation by steroid hormones. It was, therefore, of interest to compare expression of steroid hormone receptors, proliferation and apoptotic markers in the uterine endometrium of marmosets and humans. Localization of oestrogen receptor-alpha (ER-alpha) was observed in glandular epithelial cells during the proliferative phase in marmosets and in human endometria. A decrease in ER-alpha and progesterone receptor (PR-A) was observed during the mid luteal phase in both species although a postovulatory oestradiol peak is observed in human but not in marmoset. A decrease in PR-A in the late secretory phase was seen in marmoset as well as in human endometria. The proliferation marker PCNA was enhanced in the proliferative phase in both species, but it was increased in late secretory phase only in marmosets. Apoptosis as revealed by a TUNEL assay was moderate in early stage in both species. Surprisingly, apoptosis, as well as the localization of the pro-apoptotic Bcl-2 family member, Bax, was optimal in marmosets during the mid-secretory phase when plasma progesterone levels were high. On the other hand, in the human, apoptosis was maximal by TUNEL assay in late secretory phase, but Bax protein was highest in the mid-secretory phase. Thus, Bax may be initiating apoptosis in the endometrial glands as well as in the stroma. Although the pattern of steroid receptor expression in endometria of marmosets and humans are similar, proliferation and apoptosis markers appear to be regulated by other factors along with steroid hormones.     

Frequent expression of the cell death-inducing gene Bax in Reed- Sternberg cells of Hodgkin's disease

The expression of a cell death-inducing gene, Bax, was investigated in 52 cases of Hodgkin's disease in parallel with Epstein-Barr virus and was compared with the immunodetection of other apoptosis-regulating proteins, Mcl-1, Bcl-2, and Bcl-x. Bax immunostaining was found in 92% of the cases, among them 28% with a strong signal in more than 75% of the Reed-Sternberg cells. Mcl-1 was positive in 80% of the cases, whereas Bcl-2 and Bcl-x were found in 53% and 88% of the cases, respectively. Of 48 (89%) Bax-positive tumors, 43 were found to express apoptosis-inhibiting proteins such as Mcl-1 or Bcl-2. With the exception of 1 case, all Bax-positive tumors also expressed either Bcl- 2, Bcl-x, Mcl-1, or combinations of these anti-apoptotic proteins. No correlation was found between Bax expression and the presence of apoptotic cells as detected by morphology and the in situ 3' OH-DNA end- labeling technique. Our findings show that the apoptosis-inducing gene Bax expression is frequently expressed in Hodgkin's disease, providing a potential explanation for the good chemoresponses generally obtained for patients with this neoplastic disorder.     

tBHQ对无机砷诱导HaCaT细胞凋亡中的保护作用

目的观察tBHQ对内源性线粒体凋亡通路和凋亡相关蛋白Bel-2等蛋白表达的影响,探讨tBHQ在无机砷诱导HaCaT细胞凋亡过程中的作用。方法采用分光光度法检测Caspase-3蛋白活力;Westernblot法分析细胞内Caspase-3、CytC、Bcl-2和Bax蛋白表达水平。结果NaAsO2单独作用于HaCaT细胞24h,线粒体中CytC蛋白表达降低,而胞浆中CytC蛋白表达则随染砷剂量的增加而明显升高。tBHQ预处理12h后再分别暴露于NaAsO2,线粒体中CytC蛋白表达明显恢复,胞浆中CytC蛋白表达则随tBHQ剂量的增加而明显回落。此外,NaAsO。单独作用于HaCaT细胞24h,Procaspase-3蛋白表达降低,而Caspase-3活化程度均显著高于对照组（P〈0．01）,tBHQ预处理12h后再暴露于NaAsO2,Procaspase-3蛋白表达均明显高于相同浓度砷单独作用组,而且Caspase-3酶活力得到明显抑制,差异均具有统计学意义（P〈0．05）。NaAsO：单独作用于HaCaT细胞24h,与对照组相比Bcl-2蛋白表达降低,而Bax蛋白表达明显升高。tBHQ预处理12h后再分别暴露于NaAsO2,Bcl-2蛋白表达明显恢复,而Bax蛋白表达则随tBHQ剂量的增加而减少。结论tBHQ能够影响线粒体凋亡途径拮抗NaAsO2诱导的人皮肤角质细胞凋亡;tBHQ能够诱导调控凋亡相关蛋白Bcl-2／Bax从而发挥抗凋亡作用。     

Estrous cycle dependent changes in expression and distribution of Fas, Fas ligand, Bcl-2, Bax, and pro- and active caspase-3 in the rat ovary

In the present investigation, the localization of proteins involved in ovarian apoptosis were studied throughout the estrous cycle in the presence of fluctuating hormone levels. Fas, Fas ligand, Bcl-2, Bax and caspase-3 mRNA expression and proteins were detected in all ovarian tissue extracts, though the amount of protein varied with the phase of the estrous cycle. Fas, Bax and caspase-3 protein levels were highest at diestrus and decreased thereafter towards metestrus. In contrast, Fas ligand and Bcl-2 protein levels were lowest at diestrus and increased toward metestrus. Immunohistochemistry revealed that the staining of the anti-apoptotic protein Bcl-2 was more pronounced in healthy preantral follicles than in atretic follicles. In contrast, the pro-apoptotic proteins Fas, Fas ligand, Bax and active caspase-3 were more predominantly present in atretic follicles. In the ovarian surface epithelium (OSE), Fas, procaspase-3 and Bcl-2 immunostaining appeared independent of the phase of the estrous cycle. Fas ligand and Bax staining was detected particularly during proestrus in OSE cells surrounding the ovulatory follicles, while active caspase-3 was observed only in OSE cells at the postovulatory site during estrus. The proportion of luteal cells that stained positively for Fas, Bax and caspase-3 increased with the age of the corpus luteum, while Fas ligand and Bcl-2 immunostaining was strongest in newly formed corpora lutea and decreased thereafter. In conclusion, the components of the Fas signalling pathway were differentially expressed throughout the estrous cycle in a variety of ovarian cell types, which may correspond to hormone dependent survival mechanisms.     

Study on protecting effects of Baicalin and Octreotide on hepatic injury in rats with severe acute pancreatitis

AIM： To investigate the protective effects and mechanisms of Baicalin and Octreotide on hepatic injury in rats with severe acute pancreatitis （SAP）. METHODS： The SAP rat models were prepared and randomly assigned to the model control group, Baicalin treated group, and Octreotide treated group while other healthy rats were assigned to the shamoperated group. Rat mortality, levels of ALT, AST, liver and pancreas pathological changes in all groups were observed at 3, 6 and 12 h after operation. Tissue microarray （TMA） sections of hepatic tissue were prepared to observe expression levels of Bax, Bcl-2 protein and Caspase-3, and changes of apoptotic indexes.RESULTS： Rat survival at 12 h, expression levels of Bax, Caspase-3 protein and apoptotic indexes of liver were all significantly higher in treated groups than in model control group. While the liver and pancreas pathological scores, contents of ALT, AST, and expression levels of Bcl-2 protein were all lower in treated groups than in the model control group. CONCLUSION： Both Baicalin and Octreotide can protect rats with SAP by decreasing the contents of ALT, AST and expression levels of Bcl-2 protein and improving the expression levels of Bax protein, Caspase-3 protein, and inducing apoptosis.     

Expression of 11beta-hydroxysteroid dehydrogenases in bovine follicle and corpus luteum

In glucocorticoid target organs, local concentrations of active glucocorticoid are determined by the relative expression of two 11beta-hydroxysteroid dehydrogenases (HSDs): bi-directional 11beta-HSD type1 (11HSD1) that mainly activates cortisone to cortisol, and dehydrogenase 11beta-HSD type2 (11HSD2) that inactivates cortisol to cortisone. In this study, we examined the expression of mRNA encoding these two 11beta-HSDs in bovine granulosa cells harvested from preovulatory follicles and corpora lutea (CL). Ovaries were obtained from Holstein cows at a local slaughterhouse. Follicles larger than 10 mm in diameter and CL were dissected and follicular fluid and granulosa cells were taken. Corpora lutea were weighed and their stages were morphologically assessed (stage I, days 1-4; stage II, days 5-10; stage III, days 11-17; stage IV, days 8-20). Follicles were classified into four groups according to their hormonal status (oestradiol (E(2)): progesterone (P(4))>1: oestrogen active; E(2):P(4)<1: oestrogen inactive) and stage of the oestrous cycle (luteal or follicular phase). Total RNA was extracted with phenol-chloroform and subjected to a semi-quantitative RT-PCR for 11HSD1, 11HSD2 and beta-actin. Concentrations of steroids in follicular fluid were determined by an enzyme immunoassay. In granulosa cells, only 11HSD1 mRNA was detected. There was a negative correlation between the expression of 11HSD1 and the concentration of cortisol in follicular fluid (P<0.05), indicating 11HSD1 may act as a dehydrogenase in the bovine follicle. Both types of 11beta-HSDs were expressed in CL. The levels of mRNA for both isozymes were high in stage I and II, and were decreased in stage III CL. In stage IV CL, the expression of 11HSD2 but not 11HSD1 mRNA increased. These results indicate that the bovine granulosa cells and CL express 11HSD1 and 11HSD2, and they may play an important physiological role in the bovine ovary through modulating the local glucocorticoid environment.     

低分子肝素对子痫前期样大鼠肝脏保护作用研究

目的研究低分子肝素（Low Molecular Weight Heparin,LMWH）对子痫前期样大鼠肝脏组织的保护作用．并从抗细胞凋亡角度探讨其可能的作用机制。方法取10只正常非孕鼠为正常非孕组,另将30只孕鼠随机分为正常孕组、子痫前期组（preeclampsiagroup,PE组）及LMWH治疗组。PE组及LMWH治疗组孕鼠均于妊娠第13天开始给予左旋硝基精氨酸甲酯（L—NAME）200mg·kg-1·d-1皮下注射,共5d．建立子痫前期样孕鼠模型。PE组于妊娠第15～20天给予生理盐水0．5ml皮下注射,LMWH治疗组于妊娠第15～20天给予LMWH40μl·kg-1·d-1皮下注射。检测各组血压、尿蛋白及ALT、AST,对LMWH疗效进行评价;采用TUNEL法检测肝脏细胞凋亡率,荧光定量PCR及WesternBlot法检测分别检测肝脏组织中caspase-3、Bcl-2及BaxmRNA和蛋白表达。结果与PE组相比,LMWH组血压及尿蛋白显著降低（P〈0．05）,转氨酶J蝴及AST显著降低（P〈0．05）;LMWH组肝脏细胞凋亡率、Caspase-3mRNA及活化Caspase-3蛋白表达均显著低于PE组（P〈0．05）,Bcl-2mRNA及蛋白表达显著升高,而BaxmRNA及蛋白则显著降低（P〈0．05）。结论低分子肝素可以有效改善子痫前期样大鼠肝功能,减少肝脏细胞凋亡。对其肝脏具有保护作用,这一作用可能通过调节Bcl-2／Bax平衡抑制细胞凋亡。     

The expression of angiotensin and endothelin system members in bovine corpus luteum during estrous cycle and pregnancy

The aim of this study was to determine the changing profiles of the mRNA expression of members of angiotensin and endothelin system in bovine corpus luteum (CL) from different stages of the estrous cycle and pregnancy. Corpora lutea were accordingly assigned to the following stages; d 1–2, 3–4, 5–7, 8–12, 13–18, >18 (after regression) of estrous cycle and of early and late pregnancy (<4 and >4 mo). The block RT-PCR analysis of CL showed a significantly higher angiotensin converting enzyme (ACE) mRNA expression during mid and late luteal phases as well as after regression, but lower levels during pregnancy. Full quantitative real-time RT-PCR (LightCycler) confirmed this pattern of ACE mRNA expression. The angiotensin receptor type 1 (AT1R) mRNA expression was relatively stable throughout the periods examined. In contrast, AT2R mRNA temporarily decreased on d 8–12, followed by an increase to the highest levels during late luteal phase, and it remained at high levels during regression and pregnancy. Concentration of angiotensin II (Ang II) peptide in luteal tissue was highest after ovulation (d 1–2), decreased afterward, increased again during late luteal phase, and decreased to lower levels during regression and pregnancy. The mRNA expression and peptide concentration of endothelin 1 (ET-1) was high after ovulation followed by a decrease during mid and late luteal phases and increased again to the highest level after regression. The endothelin receptor type B (ETR-B) mRNA expression increased during late luteal phase and further after regression. In contrast, ETR-A and endothelin converting enzyme 1 (ECE-1) mRNA expression were relatively constant during all stages examined. In conclusion, the regulatory changes of both angiotensin and endothelin family members during early luteal phase and again during late luteal phase suggest a possible modulatory role of these vasoactive peptide families for bovine CL formation and regression.     

Derangement of apoptosis-related lymphocyte homeostasis in systemic sclerosis

OBJECTIVES: Both increased and decreased apoptosis may be involved in generating autoimmunity. This study addressed the question of whether apoptosis and apoptosis-regulating proteins are altered in systemic sclerosis (SSc). Patients and methods. Peripheral lymphocytes of 39 SSc patients and 47 healthy control persons were studied for apoptosis, Bcl-2 and Bax levels, expression of Fas (CD95) and activation markers (CD25, HLA-DR) as determined by fluorocytometry. Serum Fas and Fas ligand were measured by ELISA. RESULTS: SSc lymphocytes (mainly CD4(+)) expressed increased amounts of Bcl-2, while Bax was not elevated. Apoptosis rates of SSc lymphocytes were increased in unsupplemented medium, but returned to normal in the presence of autologous plasma. SSc patients had increased percentages of activated and CD95(+) lymphocytes and elevated soluble Fas and soluble FasL levels in serum. Activating anti-CD95 antibodies further increased the apoptosis rate. CONCLUSIONS: Increased in vitro apoptosis, elevated lymphocytic Bcl-2 content and the increased number of Fas-positive T cells are not specific for peripheral blood from SSc patients, but indicate deregulation of lymphocyte homeostasis in this disease.     

18α-甘草酸二铵对丝裂霉素C诱导的HepG2细胞凋亡的影响及机制

目的探讨18α-甘草酸二铵对丝裂霉素（MMC）诱导的HepG2细胞凋亡的影响及机制。方法18Ⅸ一甘草酸二铵不同浓度与低剂量MMC（50p．g／m1）MMC联合作用,采用MTT比色法观察MMC对HepG2细胞活性率的影响;流式细胞术分析凋亡细胞的百分率、线粒体膜电位的改变及Caspase－3的活性变化;WesternBlot检测细胞内细胞色素c的表达及凋亡相关蛋白Bcl－2／Bax的表达情况。结果单独MMC（50gg／m1）处理的HepG2细胞活性率明显降低,凋亡率显著增加,线粒体膜电位下降,Caspase-3活性增加,细胞内细胞色素C表达增加,抗凋亡蛋白Bcl-2表达减少,而促凋亡蛋白Bax表达增加。不同浓度的18α-甘草酸二铵与MMC合用组,这些指标的变化均受到抑制。结论18Ⅸ一甘草酸二铵可抑制MMC诱导的HepG2细胞凋亡,其机制可能通过调控凋亡相关蛋白的表达而实现。     

藤梨根提取物对大肠癌LoVo细胞增殖的抑制作用及诱导凋亡的影响

目的:研究藤梨根提取物(ethanol extract from radix of actinidia chinensis,EERAC)对人大肠癌LoVo细胞增殖和凋亡的影响.方法:提取藤梨根抗癌有效活性成分(EERAC),按浓度分为4处理组(10、40、160、320mg/L)和空白对照组(0mg/L).各实验组经作用24、48、72h后,进行一般形态学和AO/EB荧光染色观察;MMT法检测细胞增殖的抑制情况;免疫组织化学(immunohistochemistry,IHC)法测定LoVo细胞中凋亡相关基因Bcl-2、Bax、Caspase-3的蛋白表达变化.结果:与空白对照组比较,一般形态学显示EERAC处理组能使细胞密度减低,增殖变慢;细胞逐渐变大,细胞间接触变松,胞浆中颗粒增多,细胞脱壁现象和周围碎片增多;荧光染色观察可见处理组细胞呈橙红色荧光,细胞核出现碎片状或固缩状的凋亡特征学形态改变,凋亡现象与EERAC的浓度呈正相关性;MTT法检测显示,EERAC处理组对LoVo细胞的最佳作用时间为72h,最大抑制率为79.48%,具有浓度和时间的依赖性(P<0.01);IHC检测结果显示EERAC作用LoVo细胞24h后,Bcl-2表达明显减弱,Bax、Caspase-3表达水平明显增高,Bcl-2/Bax比值下降,差异具有统计学意义(P<0.05),其效应与浓度相关.结论:EERAC具有明显抑制LoVo细胞增殖的作用,其机制可能与降低Bcl-2表达,上调Bax、Caspase-3的表达水平,激活线粒体凋亡途径有关.     

Apoptotic chondrocyte death in human osteoarthritis

OBJECTIVE: To define apoptotic chondrocyte death and the expression of Bcl-2, Bax, and Fas in human osteoarthritis (OA) cartilage. METHODS: Cartilage samples were obtained from patients with knee OA at the time of joint replacement surgery and from normal autopsy cases. In OA, sections were obtained both from the lesional area, usually within 1 cm of bony exposure, and from the non-lesional area, which had macroscopically normal appearance or only mild surface irregularities. Apoptosis was verified by microscopic examination of hematoxylin and eosin stained specimens, TUNEL staining, electron microscopy, and DNA ladder analysis by electrophoresis. Immunohistochemistry was done to study the expression of Bcl-2, Bax, and Fas. Apoptotic cells and Bcl-2, Bax, and Fas positive cells were counted within defined microscopic fields. Expression of Bcl-2 and Bax was verified by Western blot. RESULTS: The percentage of apoptotic cells in the lesional area was significantly higher than in the non-lesional area in cartilage from the same patient with OA, while apoptotic cells were rarely seen in normal cartilage. This result was confirmed by TUNEL stain. Many chondrocytes with chromatin condensation were verified in electron microscopy, and DNA from OA lesional cartilage revealed a DNA ladder on electrophoresis. Bcl-2 and Fas expressions were significantly higher in the OA lesional area than in the non-lesional area. On the other hand, Bcl-2 expression in normal cartilage was significantly higher than in OA cartilage. There was no significant difference in Bax expression among normal, OA lesional, and OA non-lesional cartilage. CONCLUSION: These results show that apoptotic chondrocyte death occurs more frequently in OA compared to normal cartilage and in OA lesional compared to OA non-lesional cartilage. The different expression patterns of Bcl-2 and Fas in OA lesional and non-lesional cartilage suggest that they might be involved in the pathogenesis of OA.     

Apoptosis is developmentally regulated in rat growth plate

Apoptosis occurs in the growth plate during normal and abnormal longitudinal growth. To investigate the role of apoptosis during growth plate maturation, apoptosis and apoptosis-related proteins were studied in rat tibial growth plates at 2, 4, 8, and 11 wk of age. Apoptosis was studied by the terminal deoxynucleotidyl transferase (TdT)-mediated deoxy-UTP nick end-labeling (TUNEL) method, and immunohistochemistry was used to detect p53, caspase-3 and -6, the antiapoptotic proteins Bcl-2 and Bcl-x, and the proapoptotic proteins Bax and Bad. In all age groups studied, most apoptotic chondrocytes were terminal hypertrophic chondrocytes (THPCs) with a significant increase during development. At 2 wk, 0.108±0.026 THPCs were found to be apoptotic per millimeter of growth plate width; at 4 wk, 0.355±0.048; at 8 wk, 0.394±0.043; and at 11 wk, 1.084±0.069 (p<0.001; 11 wk vs 2, 4, and 8 wk). THPCs were negative for p53 immunoreactivity at 2 and 4 wk, whereas some THPCs were positive at 8 and 11 wk. Caspase-3 and -6 were found in proliferative and early hypertrophic cells at 2 wk, whereas mature hypertrophic cells and THPCs were negative. At later stages of development, mature hypertrophic cells and THPCs were stained for both caspase-3 and -6. Bcl-2 and Bcl-x were present in proliferative and early hypertrophic cells at 2 wk, whereas at older ages a decrease in staining was observed. At 2 wk of age, Bax and Bad immunoreactivities were localized in proliferative and early hypertrophic cells, whereas at 8 and 11 wk many mature hypertrophic cells and THPCs were immunoreactive for Bax and Bad. Our results show that apoptosis is developmentally regulated in the rat growth plate. In older animals, with decreased growth rate and growth plate height, apoptosis is significantly increased, especially in THPCs.