IL-12 induces T lymphocytes underging apoptosis and affects the expression and signal conduction of Bcl-2

AIM: IL-12 acts upon T lymphocytes and activates its receptor complexes of β1/β2 ,and so IL-12 can regulate TH1/TH2 balance. Our study is aimed at IL-12-inducing apoptosis of T cells and expression and signal conduction of Bcl-2 during T cell apoptosis. METHODS: The apoptosis of T cells was detected by Annexin V staining cytometry and the expression of Bcl-2 under different inhibitors were detected by the method of semi-quantitative PCR. RESULTS: IL-12 can induce the human leukemic T cell line(TIB-152) and the human lymphoma T cell line(HTB-176) and the normal human T cells to undergo apoptosis. The Bcl-2 expression at 6 hours of treatment with IL-12 increased aparently, and reached the max at 24 hours. But IL-12 did influence Bcl-2 expression. IL-12 can induce T cells to undergo apoptosis which is characterized by early membrane changes. CONCLUSION: The inducing effect is correlated with the concentration of IL-12 and the maturation of T cells. Bcl-2 takes part in the progression of T cells' apoptosis as a apoptosis mediator.     

IL-12 induces T lymphocytes apoptosis and influences the expression and signal transduction of Fas/FasL

AIM: IL-12 acts upon Tlymphocytes and activates its receptor complexes of β1/β2,and so IL-12 can regulate TH1/TH2 balance. Our study is aimed at IL-12-inducing apoptosis of Tcells and expression and signal transduction of Fas/FasLduring Tcell apoptosis. METHODS: The apoptosis of Tcells was detected by Annexin Vstaining cytometry and the expression of Fas/FasLunder different inhibitors were detected by semi-quantitative PCR. RESULTS: IL-12 induced the human leukemic Tcell line(TIB-152) and the human lymphoma Tcell line(HTB-176) and the normal human Tcells to undergo apoptosis. The FasLexpression at 6 hours after treatment with IL-12 increased apparently, and reached the max at 24 hours, and FasLexpression induced by IL-12 was inhibited by PKCinhibitor. But IL-12 did not influence Fas expression. CONCLUSIONS: IL-12 can induce Tcells to undergo apoptosis which is characterized by early membrane changes, the inducing effect is correlated with the concentration of IL-12 and the maturation of Tcells. FasLparticipates in the progression of Tcell apoptosis as a apoptosis mediator, and the effect of IL-12 on FasLexpression may be related with PKCpathway.     

The expression of CD14 in rat Kupffer cells

AIM: To explore the expression of CD14 in rat Kupffer cells (KCs). METHODS: In rat KCs induced by LPS or the mediators from KCs induced by LPS, the changes of CD14 expression were measured by RT-PCR and immunohistochemistry.The expressions of TNFα mRNA、IL-6 mRNA or the concentrations of TNFα、IL-6 were estimated by in situ hybridization and radioimmunoassay, respectively. RESULTS: LPS increased the expression of CD14 in KCs in a dose-dependent fashion (LPS, 1 μg/L-10 mg/L) and in a time-dependent fashion(0.5 h-24 h, peaked at 3-6 hours). While the expression of CD14 in KCs stimulated by the active mediators from KCs which had been exposed to LPS 1 hour were obviously increased. CONCLUSIONS: There was a close relationship between LPS or the active mediators from KCs induced by LPS and the expressions of CD14. It is implied that the increase in CD14 expression may be induced by LPS and the cytokines produced by KCs, it also reveals that there is a auto-regulated loop in CD14 expression.     

Effects of Fas,NF-κB and caspases on microvascular endothelial cell apoptosis induced by TNFα

AIM:To study the apoptotic effect of TNFα on rat pulmonary microvascular endothelial cells(PMVEC)and the role of Fas, NF-κB in its mechanism. METHODS: Apoptosis of PMVEC was analyzed and quantitated with TUNEL, flow cytometer. Northern blot was applied to assess the influence of TNFα on PMVEC Fas expression. Fas antibody was used to investigate the apoptotic effect of Fas on PMVEC. Activation of caspase-8 was examined by Western blot. Expression of caspase-3 was analyzed with histo-immunochemical staining. RESULTS:Growth curve showed that TNFα suppressed endothelial cell proliferation in a dose-dependent manner. After treatment with 5×10⁶U/LTNFα, apoptotic rate was 14.0%±3.1% detected with TUNEL, and 13.1% with flow cytometer. When the cells were co-cultured with TNFα and APDC, an NF-κB inhibitor, less cells were viable and more cells were positively stained with TUNEL. Fas expression in PMVEC was elevated after TNFα treatment. Co-culturing with Anti-Fas antibody aggravated PMVEC apoptosis. Caspase-8 activity and caspase-3 expression was elevated. Caspase-3 inhibitor significantly ameliorated PMVEC apoptosis. CONCLUSION: Large dose of TNFα(5×10⁶U/L) can induce apoptosis in rat PMVEC. NF-κB has an anti-apoptotic effect in PMVEC. TNFα up-regulates Fas expression in PMVEC, and the latter takes a part in apoptosis. Caspase-8 and caspase-3 are involved in PMVEC apoptosis induced by TNFα.     

Fibronectin supports endotoxemia mice survival

AIM:To study the preventive effect of fibronectin on hepatic failure induced by endotoxin in mice.METHODS:The survival rate was observed in endotoxemia mice injected with fibronectin from human plasma. The tissue damage and expression of TNFα, IL-1β, IL-6 mRNA in hepatocyte were detected by the methods of histology, ultrastructure, DNA fragementation and RT-PCR.RESULTS:①Fibronectin obviously reduced the mortality of endotoxemia mice sensitized by D-galactosamine(GalN). ②Histopathology showed that less necrosis occurred on the hepatocyte of endotoxemia mice injected with fibronectin, compared with saline control. ③Ultrastructure and DNA fragmentation showed fibronectin suppressed hepatocyte apoptosis induced by LPS. ④Fibronectin down-regulated the overexpression of TNFα, IL-1β, IL-6 mRNA on hepatocyte induced by LPS.CONCLUSION:Fibronectin supports endotoxemia mice surrival by down-regulating the expression of TNFα, IL-β, IL-6, it may be a potent therapy for endotoxemia.     

Effects of lipopolysaccharide,IL-6 and TNFα on the tissue factor expression of astrocytes

AIM:To study the effects of lipopolysaccharide(LPS), interleukin-6(IL-6)and tumor necrosis factor α (TNFα) on tissue factor(TF) expression of astrocytes. METHODS:Astrocytes were identified with anti-glial fibrillary acidic protein antibody. The TF activity of cell lysate was measured with one stage clotting assay. RESULTS:TF activity of astrocytes of LPS,IL-6,TNFα groups were obviously higher than that of the control group(P <0.05); While LPS,IL-6 and TNFα were combined with trifluoperazine or H₇, their inductive effects were inhibited. CONCLUSION:LPS,IL-6 and TNFα promoted the TF expression of astrocytes and its mechanisms may connected with Calcium/Camodulin and protein kinase C pathway.     

Expression of cytokines and their receptors in leukemia cell lines and normal blood cells

AIM: To study the expression of cytokines and their receptors in leukemia cell lines and normal blood cells. METHODS: RT-PCR was used to detect expression of mRNA for cytokines in leukemia cell lines(HL-60,U937,K562,HEL,DAMI,MEG-01,HUT78 and CA) and normal blood cells, including CD34⁺ cells, megakaryocytes,platelets, peripheral mononucleates cells and granulocytes. RESULTS: ①CD34⁺ cells simultaneously expressed mRNA for IL-1(α,β),IL-3, IL-6 , G-CSF, GM-CSF and their receptors and SCFR,MPL as well. The granulocytes only expressed IL-6,IL-6R,G-CSFR,GM-CSF. Megakaryocytes and platelets only expressed IL-3R,IL-6,IL-6R,MPL.Interestingly, TGFβ₁ ,TNFα and their receptors sustained to express in normal cells.②Most leukemia cell lines were found to simultaneously express at least two or more stimulating cytokines and receptors ,while TGFβ 1 , TNFα and their receptors were expressed in all the leukemia cell lines we observed. CONCLUSIONS: ①Multi-autocrine loops exist in leukemia cells;②Imbalance of autocrine loops of positive and negative cytokines may be related to leukemia.     

Dengue virus type 2 induces apoptosis and expression of death receptor in hepatic veno-endotheliocyte ED25

AIM: To investigate apoptosis and the expression of death receptors of TRAIL,TNF and Fas on hepatic veno-endotheliocyte ED25 cell strain induced by dengue virus type 2(DV2).METHODS: Flow cytometric analysis was used to detect the number of apoptotic cells and the expression levels of TRAILR1-4 ，TNFR1-2，Fas on ED25 cells before/after DV2 infection.RESULTS: The numbers of apoptotic cells of ED25 increased after DV2 infection,there were only about 5.7%±1.2% of apoptotic cells before virus infection while there were approximately 27.3%±1.6% of apoptotic cells after virus infection.At the same time the expression level of Fas also increased,before virus infection about 44.3%±2.2% of ED25 cells expressed Fas while 63.0%±2.3% of ED25 cells expressed Fas after virus infection.CONCLUSION: DV2 infection can induce apoptosis of ED25 cells,and it suggests strongly that Fas/FasL may be involved in the apoptotic signal transduction.     

Mechanisms of nitric oxide synthesis induced by human complement C5b-9complex in glomerular mesangial cells of rats

AIM: To explore the mechanism of the nitric oxide (NO) synthesis induced by human C5b-9 complex in glomerular mesangial cells(MC) of rats. METHODS: The MC of rats were cultured and stimulated with human complement C5b-9 complex to induce TNFα and IL-1β. At the same time, several parameters related to NO synthesis were measured at 3 h, 6 h and 24 h after C5b-9 stimulation. The effects of monoclonal antibodies against TNFα and IL-1β on NO synthesis were examined in this system. RESULTS: TNFα concentration in supernatant from MC in C5b-9 group was higher than that of control group at 6, 24 h after stimulation with C5b-9 complex and reversed by adding anti-TNFα McAb. C5b-9 complex didn't stimulate the release of IL-1β in same system. In addition, the expression of iNOS mRNA in MC was observed at 3 h after stimulation with C5b-9. Levels of iNOS mRNA expression and cGMP in MC and NO₃^-/NO₂^- in supernatant from MC in C5b-9 group were higher than those in control group at 6, 24 h after C5b-9 stimulation, these changes were also reversed by adding monoclonal antibody against TNFα. CONCLUSION: C5b-9 complex could induce iNOS mRNA expression at 3 h after C5b-9 stimulation, and the synthesis of NO at 6, 24 h was related to TNFα released from cultured MC of rats by C5b-9 complex to a certain extent.     

Effects of TNFα and IL-10 on cytomegalovirus infection in human embryonic lung fibroblasts

AIM:To study effects of tumour necrosis factor alpha(TNFα) and interleukin-10(IL-10) on human cytomegalovirus AD169 (HCMV AD169) infection in human embryonic lung fibroblasts (HEL),and the ability of the infected HEL to produce TNFα. We have attempted to understand the effect of cytokines in the immune of HCMV infection. METHODS:TNFα、IL-10 were added separately with different concentrations before 24 h HCMV infection of HEL to study the effect of TNFα and IL-10 on multiplication of HCMV. HCMV was incubated with HEL, TNFα in culture supernatants were measured at 4, 24, 48, 72, 96 h postinfection. The level of TNFα was measured by enzyme-linked immunosorbent assay( ELISA). RESULTS:The addition of TNFα with the concentration of 10-100 μg/L or IL-10 with the concentration of 1-10 μg/L before 24 h HCMV infection of HEL could remarkably inhibited the multiplication of HCMV in HEL. Level of TNFα didn't increase in infected cell supernatants. CONCLUSION:TNFα and IL-10 play an important role in the immune of HCMV infection.     

Effects of leptin on hypoxia-reoxygenation induced apoptosis in human L02 cells and expression of Fas and FasL

AIM: To observe the effect of leptin (LEP) on hypoxia-reoxygenation induced apoptosis in L02 cells.METHODS: In the experiment, L02 cell injury was induced by hypoxic air (95%N2 and 5% CO2). The cultured L02 cells were divided into hypoxic 12 h group (IR group) alone, normal control group and the hypoxic plus leptin (100 μg/L, 200μg/L, 400 μg/L, 800 μg/L and 1 600 μg/L) treatment groups in vitro. Flow cytometry, terminal dUTP nick-end labeling (TUNEL) assay and fluorescent quantitative PCR were used to measure the changes of apoptosis in L02 cells and expression of Fas/FasL mRNA.RESULTS: (1) The percentage of L02 cells apoptosis and positive TUNEL cells significantly increased in IR group compared to control group (P<0.01). When L02 cells were treated with LEP, the percentage of cell apoptosis and positive TUNEL cells were decreased compared to IR group. (2) Compared to control group, the Fas/FasL mRNA expression significantly increased in IR group (P<0.01). When L02 cells were treated with LEP, the Fas/FasL mRNA expression decreased compared to IR group, the effect of LEP at concentration of 400 μg/L was obviously (P<0.05). CONCLUSION: LEP decreases the apoptosis of hypoxic-reoxygenation L02 cells by down-regulation of Fas/FasL mRNA expression in L02 cells.     

Influence of GPIF on the expression of costimulatory molecules lineaged T cells in mice with immunodeficiency in vivo

AIM:To investigate the effects of goat placenta immunoregulating factor (GPIF) on the expression of costimulatory molecules lineaged T cells in BALB/c mice. METHODS:Animal model for immunodeficiency made from BALB/c mice with whole-body irradiation by 5 Gy 60Coγ-ray was applied for research. The immunosuppressive mice were injected with GPIF for seven days continuously. FACS was applied to analyze the rate of CD28+, CD152+, CD4+CD28+, CD8+CD28+, CD4+CD152+ and CD8+CD152+ cells in splenic lymphocytes and ELISA method was employed to measure the amount of IL-2 and IFN-γ in serum of mice. RESULTS:GPIF increased the percentage of CD28+, CD4+CD28+ and CD8+CD28+ cells (P<0.05, P<0.01), and decreased the percentage of CD152+ (P<0.05, P<0.01), CD4+CD152+ cells (P<0.05, P<0.01) in splenic lymphocytes of immunosuppressive mice significantly. GPIF increased the content of IL-2 and IFN-γ in serum of mice simultaneously (P<0.01). CONCLUSION:Immuno-enhancing effect of GPIF facilitates the costimulation of CD28 pathway, which can activate T cells and accelerate the course of renewing T cell activity. The function of GPIF may have close relationship with an immune network formed by the secretion of IL-2 and IFN-γ and the expression of CD28 and CD152.     

Toosendanin exerts synergistic effect on γδ T cell-induced cytotoxicity to colorectal cancer by suppressing expression of MCL-1

AIM: To investigate the synergistic effect of toosendanin on regulating the cytotoxicity of γδ T cells to colorectal cancer cells. METHODS: γδ T cells amplified in vitro were identified by flow cytometry. Lactate dehydrogenase (LDH) release was detected to evaluate the cytotoxicity of γδ T cells and toosendanin to SW480 cells. The role of toosendanin in regulating the protein expression of Bcl-xL, Bcl-2 and MCL-1 was determined by Western blot. The effect of toosendanin on regulating the secretion of TNF-related apoptosis-inducing ligand (TRAIL) and Fas ligand (FasL) by γδ T cells was evaluated by ELISA. The mitochondrial membrane potential and apoptosis in SW480 cells treated with γδ T cells and toosendanin were analyzed by flow cytometry. The activation of caspase-9 and caspase-3 were determined by Western blot. RESULTS: CD3 and γδ T-cell receptor (TCR) were highly expressed in the γδ T cells amplified in vitro. Combination with toosendanin significantly enhanced the cytotoxicity of γδ T cells to SW480 cells. Toosendanin did not influence the secretion of TRAIL and FasL secreted by γδ T cells. Toosendanin did not regulate the expression of Bcl-xL and Bcl-2 but suppressed the expression of MCL-1 in SW480 cells. In addition, enforced expression of MCL-1 obviously suppressed the synergistic effect of toosendanin on γδ T cell-induced cell death in SW480 cells. Meanwhile, co-treatment with toosendanin was able to enhance the γδ T cell-induced apoptosis and decrease of mitochondrial membrane potential. γδ T cell-dependent activation of caspase-9 and caspase-3 was significantly enhanced by toosendanin co-treatment in SW480 cells. CONCLUSION: Toosendanin exerts synergistic effect on γδ T cell-induced cytotoxicity to colorectal cancer by suppressing the expression of MCL-1.     

Effect of respiratory syncytial virus on apoptosis and expressions of FasL,Fas, Bcl-2 and Bax

AIM: To study the relationship between respiratory syncytial virus (RSV) infection and apoptosis, between RSV infection and expressions of FasL, Fas, Bcl-2 and Bax. METHODS: Apoptotic cells were examined by flow cytometry and transmission electron microscope. Immunohistochemical analysis was used to detect the expressions of apoptosis-associated gene FasL, Fas, Bcl-2 and Bax in A549 cells during RSV infection. RESULTS: Apoptotic index increased at 72 h and 120 h postinfection. Apoptotic cells were detected by transmission electron microscope. High-expressions of FasL, Fas and Bax genes and low-expression of Bcl-2 gene were detected by immunohistochemical staining. CONCLUSION: Apoptosis in A549 cells was induced by RSV infection. This apoptosis may be induced by up-regulating the expression of FasL, Fas, Bax genes and down-regulating the expression of Bcl-2 gene.     

The mechanism of apoptosis induced by homoharringtonine in HL-60 cells

AIM: To study the signal transduction pathway of apoptosis initiation induced by homoharringtonine in HL-60 cells. METHODS: After establishing the model of apoptosis initiation induced by homoharringtonine in HL-60 cells, at the point of apoptosis initiation, molecular caspase-3, Bcl-2, Bax and Fas/FasL were measured with flow cytometry and transmission electron microscope. ERK2 and P38 expression in HL-60 cells were detected by using immunohistochemistry. RESULTS: The model of apoptosis initiation induced by homoharringtonine was established in HL-60 cells. At the point of apoptosis initiation, upregulation of caspase-3 and decrease in Bcl-2/Bax were observed. However, the expression of Fas/FasL did not significantly change. ERK2 expression decreased and P38 expression increased. CONCLUSIONS: Caspase-3, Bcl-2, Bax and mitogen activated protein kinase pathways were involved in signal transduction of apoptosis initiation induced by homoharringtonine in HL-60 cells.     

Effects of PTEN on apoptosis,oxidative damage and immune inflammatory factors in myocardial H9c2 cells with anoxia/reoxygenation

AIM: To investigate the effects of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) on the apoptosis, oxidative damage and immune inflammatory factors in myocardial H9c2 cells with anoxia/reoxygenation (A/R). METHODS: The H9c2 cells were used to establish a model of A/R. The H9c2 cells were transfected with PTEN small interfering RNA (siRNA) and negative control. After A/R, the expression of PTEN at mRNA and protein levels was determined by RT-PCR and Western blot, respectively. The cell viability was measured by MTT assay. The apoptosis was analyzed by flow cytometry. Xanthine oxidase method was used to determine superoxide dismutase (SOD) activity. The content of malondialdehyde (MDA) was detected by thiobarbituric acid method. The lactate dehydrogenase (LDH) activity in the supernatant was evaluated by 4-dinitrophenylhydrazine method. The levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6 in culture supernatant were examined by ELISA. The protein levels of cleaved caspase-3, Bax and FasL in the cells were determined by Western blot. RESULTS: After A/R, the expression of PTEN at mRNA and protein levels was significantly increased in the H9c2 cells (P<0.05). The mRNA and protein levels of PTEN were decreased significantly after transfection with PTEN siRNA (P<0.05). The viability of H9c2 cells was decreased after A/R, while the apoptotic rate was increased. The protein levels of cleaved caspase-3, Bax and FasL were increased in the cells. The MDA level was elevated, the activity of SOD was decreased, and the levels of LDH, TNF-α, IL-1β and IL-6 in the culture supernatant were increased (P<0.05). Down-regulation of PTEN partly antagonized the effects of A/R on the viability, apoptotic rate, MDA content, SOD activity, and the levels of LDH, TNF-α, IL-1β and IL-6 in culture supernatant. CONCLUSION: Down-regulation of PTEN attenuates oxidative damage induced by A/R, reduces apoptosis and secretion levels of TNF-α, IL-1β and IL-6 in the H9c2 cells.     

Relation between TNF-α,TNFR I expression and apoptosis in oral lichen planus

AIM: To examine the expression and distribution of tumor necrosis factor-α (TNF-α), tumor necrosis factor receptor I (TNFR I) and apoptosis in oral lichen planus, and evaluate their roles and relation in the oral lichen. METHODS: Immunohistochemical technique and TUNEL were employed to study the expression of TNF-α, TNFR I and apoptosis in 50 cases of oral lichen planus and 10 normal oral mucosa specimens. RESULTS: Compared with the normal control group, TNF-α expression was upregulated in mononuclear cells in lamina propria and decreased in keratinocytes in oral lichen planus lesion (P<0.05). On the contrary, TNFR I expression was increased in keratinocytes and decreased in lamina propria in oral lichen planus lesion (P<0.05). The increased apoptosis index in keratinocytes and the decreased apoptosis index in lamina propria were found in oral lichen planus (P<0.05). CONCLUSION: The accelerated apoptosis of keratinocytes and the inhibition of lymphocytes apoptosis may contribute to the formation and progression of oral lichen planus.     

Effects of Tertram ethylpyrazine on expression of Fas/FasL mRNA in lung tissue with ischemia-reperfusion injury in rabbits

AIM: To study the expression of Fas/FasL mRNA in lung tissue with ischemia-reperfusion lung injury in rabbits and the relationship with the apoptosis,and to observe the effects of Tertram ethylpyrazine on them.METHODS: The pulmonary ischemia-reperfusion models in rabbits with occlusion of left pulmonary hilum for 1 h and then reperfusion 1,3,5 h respectively were used in this experiment.In TMP group,Tertram ethylpyrazine was intravenously dropped at dose of 60 mg/kg at 1 h before ischemia.The TUNEL technique was used to explore apoptotsis of pulmonary cells.In situ hybridization was performed on the rabbit lung tissue to assay the expression of Fas/FasL mRNA.RESULTS: Apoptosis of pulmonary cells was found in both IR group and TMP group.Compared with group IR,the apoptosis index (AI) was decreased obviously in group TMP (P<0.01).There was a significant positive correlation between the expression of Fas/FasL mRNA and the apoptosis of pulmonary cells (r₁=0.900,r₂=0.869,P<0.01).CONCLUSION: The activation of Fas/Fas-L system may contribute significantly to induce pneumocyte apoptosis in pulmonary ischemic injury.Tertram ethylpyrazine inhibits the activation of Fas/FasL system to decrease apoptosis in pulmonary tissue,which may protect the pulmonary tissues in ischemia injury.     

Mechanisms underlying the induction of IL-2 secretion by PDB pl us ionomycin in CD4+CD25+ T cells from cord blood and adult peripheral blood

AIM:To confirm that CD4+CD25+ regulato ry T cells don't have an instinctive defection in IL-2 secretion,and to have an insight into the maturation state of CD4+CD25+ T cells in cord blood.METHODS:CD4+CD25+ and CD4+CD25- T cells were purified f rom cord blood of term infants (CB) and adult peripheral blood (PB) by autoMACS,and stimulated with PDB plus ionomycin.After 45 hours of culture,cells were d etected for expression of CD69 and CD25 by flow cytometry,and the supernatants were measured for 7 kinds of cytokines by Luminex.RESULTS:CD4+CD25+ T cells from both CB and PB proliferated comparably with CD4+CD25- T cells when stimulated with PDB plus ionomycin.A fter 45 hours of culture,however,the CD4+CD25+ T cells underwent a tendenc y of cell death.Expression of CD25 was further upregulated when CD25+ cells w ere activated.Under stimulation of PDB plus ionomycin,both CD4+CD25+ and C D4+CD25- T cells in PB secreted high levels of IFN-γ,IL-2 and TNF-α,with CD25+ cells secreted much higher level of IL-5,IL-4 and IL-10 than those in CD25- cells;CD4+CD25+ and CD4+CD25- T cells in CB also secreted high level of IL-2 and TNF-α but much lower level of IFN-γ than those in PB,and no secretion of IL-5,IL-4 and IL-10 was observed.CONCLUSION:CD4+CD25+ regulatory T cells don't have an i nstinctive defection in IL-2 secretion,otherwise there may be a different TCR signaling pattern in CD4+CD25+ T cells from traditional T cells.The CD4+C D25+ T cells in cord blood have not fully matured in function.     

The function of Fas,FasL and Bcl-2 in the pathogenesis of autoimmune thyroid disorders

AIM: To investigate the expression and function of apoptosis-related protein, Fas, FasL, and Bcl-2 in the pathogenesis of autoimmune thyroiditis. METHODS: Immunohistochemical staining was performed on 20 Hashimoto's thyroiditis (HT), 20 Graves' disease (GD), and 20 thyroid follicular adenoma (TFA, as control).RESULTS: All the cases expressed Fas, mainly on the cell surface and cytoplasm. FasL was found in all except 3 of the TFA. Bcl-2 in 15 of HT, 19 of GD, 17 of TFA. In TFA follicular cells expressed moderate Fas and minimal or absent FasL. In HT, follicles adjacent to infiltrating lymphocytes showed a increased levels of Fas and FasL, but infiltrating lymphocytes exhibited weaker staining of Fas and FasL than thyrocytes. In GD, thyrocytes and lymphocytes showed nearly similar Fas with HT, but rather weaker for FasL than HT. Bcl-2 was nearly similar in GD and TFA, but follicular cells in vicinity of lymphocytes and lymphocytes located in germinal centers of HT tissues exhibited significantly weaker. CONCLUSION: The expression of Fas, FasL and Bcl-2 in Hashimoto's thyroiditis and Graves' disease was nearly similar. Strong FasL expression and weak Bcl-2 expression on the follicles in HT may induce apoptosis. These results provide further proof that the functions of Fas and its ligand and Bcl-2 may play an important part in the pathogenesis of autoimmune thyroid diseases. The lymphocytes do not seem to be directly engaged in the process with their own FasL, but they may provide some cytokines that , in turn , up-regulates Fas and/or FasL leading to apoptosis.