DNA-dependent RNA polymerase enzymes affected in uraemic lymphocyte cells

The DNA-dependent RNA polymerase activity and endonucleases in uraemic lymphocyte cells were investigated. It was found that the activity and quantity in three classes of polymerases are remarkably reduced. The reduction in enzyme activity is accompanied by increasing endonuclease activity. The relationship of polymerase enzymes with endonucleases is discussed.     

Transmembrane signalling in human monocyte/mesangial cell co-cultures: role of cytosolic Ca(2+).

BACKGROUND: Adhesion of monocytes triggers apoptosis, cytotoxicity, cytokine release, and later proliferation of cultured human mesangial cells (HMC). In the search for transmembrane signals transducing the interaction of HMC adhesion molecules with leukocyte counterreceptors, we measured variations of cytosolic Ca(2+) ([Ca(2+)](i)) in HMC and monocytes of the U937 cell line during 6-h co-cultures. METHODS: Monolayer cultures of HMC and suspensions of U937 cells were loaded with the fluoroprobe fura 2-AM and subsequently co-cultured for 6 h while separately monitoring by microfluorometry the Ca(2+)-dependent 500 nm fluorescent emission of each cell line at fixed intervals upon excitation at 340/380 nm. RESULTS: U937 and peripheral blood monocyte adhesion was followed in HMC by a slow, progressive rise of [Ca(2+)](i) from basal levels of 96+/-9 nM to 339+/-54 at 60 min and 439+/-44 nM at 3 h. The [Ca(2+)](i) elevation reached a steady state thereafter, while parallel monolayers incubated with control media maintained resting levels throughout the co-culture with stable fluoroprobe retention. Receptor sensitivity to vasoconstrictor agents, including compounds not released by monocytes, such as angiotensin II, was rapidly downregulated in HMC co-cultured with U937 cells. No [Ca(2+)](i) changes could be elicited by the octapeptide or by the TxA(2) analogue, U-46619, as early as 30 min after exposure to U937 cells. No [Ca(2+)](i) changes were observed in U937 cells throughout the co-culture. Conditioned media from monocytes and from co-cultured HMC+U937 cells had no effect on [Ca(2+)](i) of HMC. Ca(2+) entry leading to fura 2 saturation was still inducible by Ca(2+) ionophores, such as ionomycin and 4-Br-A23187, which also inhibited the responses to vasoconstrictors. Ca(2+)-free solutions prevented the [Ca(2+)](i) rise as well as subsequent receptor inactivation, implicating Ca(2+) influx through store-operated Ca(2+) channels (SOC), a major pathway for Ca(2+) entry in these cultured cells. Ca(2+) influx was confirmed by Mn(2+)-quenching of fura 2. CONCLUSIONS: In HMC, early changes in [Ca(2+)](i) signal for monocyte adhesion in a co-culture model of glomerular inflammation. This signalling mechanism may mediate the functional responses elicited in glomerular cells by leukocytes, including downregulation of receptors for vasoactive agents.     

Deoxyribonuclease activity in lymphocytes of patients with chronic renal failure treated conservatively

The activity of nucleases and concentrations of highly important metal ions in T and B lymphocytes were examined. The source of lymphocyte was the blood of patients with chronic renal failure and activity of enzyme as well as ion concentrations were compared to the control group. Concomitant with the increase in enzyme activity was an increase of metal ion concentrations assayed in both T and B lymphocytes isolated from patients with renal disease. The data suggest that the enhancement of nuclease activity is a result of increased enzyme polypeptide synthesis and its stimulation by metal ions. Utilization of the nuclease test for monitoring uraemic toxicity is considered.     

Effects of isoflurane and xenon on Ba2+-currents mediated by N-type calcium channels

Background. Isoflurane and xenon are inhalation general anaestheticswith differing clinical profiles and contrasting synaptic actions.Both agents have been shown to depress excitatory synaptic responses.Whether this is via pre-synaptic or post-synaptic mechanismshas not been determined clearly. N-type calcium channels area putative pre-synaptic target for these agents. We tested whetherN-type calcium channels were sensitive to isoflurane and xenonand whether there was any stereoselectivity in the effect ofisoflurane. Methods. We used patch-clamp electrophysiology on isolated HEK293cells stably expressing N-type calcium channels to investigatethe effects of isoflurane and xenon on barium currents mediatedby N-type calcium channels. Results. Racemic isoflurane caused a concentration-dependentreduction (11–35%) in the peak current through the N-typechannels in the concentration range 0.15–1.22 mM. In theclinically relevant concentration range the inhibition was small.At an isoflurane concentration of 0.31 mM (equivalent to 1 MAC),the peak N-type current was inhibited by 14 (1)%. The opticalisomers of isoflurane were found to be equally potent at inhibitingcurrents through N-type channels. The inert gas anaestheticxenon was found to have no measureable effect on N-type channelsat a concentration of 3.4 mM (1 MAC). Conclusions. These results suggest that N-type calcium channelsare not the targets mediating general anaesthesia with thesetwo inhalation agents. Declaration of interest. Professor Franks is a board memberof an Imperial College spin-out company, Protexeon Ltd, thatis interested in developing clinical applications for medicalgases, including xenon. Professor Franks is a paid consultantin this activity. In addition Air Products have funded workin the authors' laboratories that bears on the actions of xenonas an anaesthetic and neuroprotectant. Air Products has a financialstake in Protexeon Ltd.     

Inhibition by uraemic sera of CD4+ T-cell adhesion to extracellular matrix components

BACKGROUND.: T-cell-mediated immune responses are impaired in patients withchronic renal failure. The migration, proliferation, differentiation,biological functioning, and interaction with other T cells aremediated by cell surface adhesion proteins, which include integrins. METHODS.: To elucidate how uraemia can impair T-cell-mediated responsesin vivo, the effects of sera from uraemic patients on T-cellproliferation and adhesion to extracellular matrix (ECM) componentswere examined. RESULTS.: Preincubation of human CD4⁺ T cells with sera from undialysedand dialysed (haemodialysis or peritoneal dialysis) uraemicpatients inhibited the capacity of the cells to be stimulatedby phytohaemmagglutinin and by anti-CD3 monoclonal antibodyplus immobilized fibronectin (FN). Sera from uraemic and dialysedpatients, but not from healthy individuals, inhibited significantly,and in a dose-dependent fashion, human CD4⁺ T cell adhesionto immobilized FN and laminin (LN). The degree of inhibitionof adhesion was similar whether the sera were continuously present,even during the adhesion assay, or removed by washing. The adhesioninhibiting capacity of the uraemic sera was not due to modificationof the expression of ß1 integrins on the surfacesof the T cells. CONCLUSIONS.: These results suggest that uraemia can impair the proliferativecapacity and adhesion of immune cells, and thus may affect normalimmune processes and contribute to the overall immune deficiencyobserved in patients with renal failure.     

Distinct Ca2+ channels mediate transmitter release at excitatory synapses displaying different dynamic properties in rat neocortex

To study the type of presynaptic calcium channels controlling transmitter release at synaptic connections displaying depression or facilitation, dual whole cell recordings combined with biocytin labelling were performed in acute slices from motor cortex of 17- to 22-day-old rats. Layer V postsynaptic interneurons displayed either fast spiking (FS) (n = 12) or burst firing (BF) (n = 12) behaviour. The axons of FS cells ramified preferentially around pyramidal cell somata, while BF cell axons ramified predominately around pyramidal cell dendrites. Synapses between pyramidal cells and FS cells displayed brief train depression (n = 12). Bath application of omega-Agatoxin IVA (0.5 microM), blocking P/Q-type calcium channels, decreased mean peak amplitudes of the EPSPs to 40% of control EPSPs (n = 8). Failure rate of the EPSPs after the first presynaptic action potential increased from 9 +/- 11 to 28 +/- 15%. This was associated with an increase in paired pulse ratio of 152 +/- 44%. Omega-conotoxin GVIA (1-10 microM), selectively blocking N-type calcium channels, had no effect on peak amplitudes or frequency dependent properties of these connections (n = 5). Synapses from pyramidal cells to BF cells displayed brief train facilitation (n = 8). Application of omega-Conotoxin in these connections decreased peak amplitudes of the EPSPs to 15% of control EPSPs (n = 6) and decreased the paired pulse ratio by 41 +/- 30%. Omega-agatoxin did not have any significant effect on the EPSPs elicited in BF cells. This study indicates that P/Q-type calcium channels are associated with transmitter release at connections displaying synaptic depression, whereas N-type channels are predominantly associated with connections displaying facilitation.     

Angiotensin-II-induced cell hypertrophy: potential role of impaired proteolytic activity in cultured LLC-PK1 cells

BACKGROUND: Angiotensin II-induced hypertrophy of both mesangial and tubularcells has been shown to be caused by enhanced protein synthesis.There are no data about its role on protein breakdown. Therefore,protein turnover and proteolytic activities were investigatedin LLC-PKI cells. METHODS: Protein turnover was measured by determining the incorporationand release of [¹⁴C]phenylalanine; collagenolytic and gelatinolyticactivities were assayed by using fluorogenic peptidyl substrates. RESULTS: Angiotensin II (10^–8–10^–6M) exerted a dose-dependentinhibition of collagenolytic and gelatinolytic activities, associatedwith reduction of protein degradation rate. In addition angiotensinII stimulated protein synthesis in the cells. These combinedeffects on protein turnover resulted in an increase in bothcell size and cell protein content (31.7% after 48 h). However,the rise of cell protein content was only partly (48.0%) preventedby the protein synthesis inhibitor cycloheximide (10^–5M),which supports the role of decreased protein degradation inthe angiotensin II-induced cell hypertrophy. The angiotensin-II-inducedeffects on proteolytic activities as well as on cell proteincontent could be abolished by coincubation with the angiotensinII type I-receptor antagonist DuP 753 (10^–6M). The calcium-channelblocker verapamil (10^–6M) ameliorated the impairment ofcollagenolytic activity. On the contrary the calcium ionophoreA23187 (10^–6M) mimicked the action of angiotensin II onthis enzyme activity (control 34.5± 1.9; angiotensinII 24.0±2.0; A23187 23.0±2.2 and angiotensin II+ verapamil, 33.8±2.6 pmol/min/µg DNA). The roleof cytosolic [Ca²⁺] in the actions of angiotensin II could befinally shown by a dose-dependent rise which was partly bluntedby verapamil. CONCLUSION: The angiotensin-II-induced hypertrophy in LLC-PK1 cells is causednot only by enhanced protein synthesis but also by reduced proteindegradation. The concomitant decline of collagenolytic and gelatinolyticactivities may contribute to the accumulation of extracellularmatrix, and presumably also to cell hypertrophy. These effectsare obviously mediated via angiotensin II type I receptors andseem to be [Ca²⁺] dependent.     

Strong depletion of CD14(+)CD16(+) monocytes during haemodialysis treatment.

BACKGROUND: The immune defect in haemodialysis (HD) patients is associated with a monocytic dysfunction, including an increased production of proinflammatory cytokines. Monocytes fall into subpopulations comprising CD14(++)CD16(-) and CD14(+)CD16(+) cells. Circulating numbers of the latter can rapidly increase during infectious episodes and inflammation. METHODS: We determined the amount of CD14(+)CD16(+) monocytes in HD patients and characterized their fate during HD treatment. In 34 HD patients and 17 healthy controls, the distinct cell populations were determined by differential blood counts and flow cytometry. Cells from 14 HD patients were analysed at the start, 10, 30 and 120 min thereafter, and at the end of HD treatment. RESULTS: Before HD, patients show a monocytosis with a strongly increased CD14(+)CD16(+) subpopulation. Early during HD treatment, circulating leukocyte numbers decrease, with monocytes being most profoundly influenced. Interestingly, among them, sequestration is most pronounced in the CD14(+) CD16(+) subpopulation. After 30 min, approximately 83+/-9% of CD14(+)CD16(+) cells are removed from circulation. This sequestration does not differ between patients treated with polyamide or haemophan membranes. The sequestration is a short-lived temporary effect and cell numbers are replenished within 120 min of treatment for the entire monocyte population. Beyond that time point, cellular activation by the dialyser membrane becomes visible. Reappearence kinetics of CD14(+)CD16(+) monocytes is slower; however, initial numbers are reached by the end of treatment. CONCLUSION: Haemodiaysis leads to temporary removal of monocytes from the bloodstream followed by the reappearance of activated cells. This might contribute to the state of chronic microinflammation, which is reflected by high levels of CD14(+)CD16(+) monocytes.     

Halothane does not inhibit synthesis of nucleic acids in Tetrahymena pyriformis

The effect of halothane on precursor incorporation into nucleic acids was studied in Tetrahymena pyriformis, a ciliate protozoan. At concentrations that blocked cell division (1.2 and 2.4 per cent), halothane inhibited incorporation of 14C-thymidine and 14C-uridine into DNA and RNA, respectively, in intact cells. However, in nuclei isolated from T. pyriformis, the anesthetic did not inhibit DNA and RNA synthesis when these processes were assayed using the nucleoside triphosphates (3H-thymidine triphosphate and 3H-uridine triphosphate) as precursors. It is concluded that halothane does not directly inhibit nucleic acid synthesis (i.e., the nucleic acid polymerase reactions), and that the inhibition of precursor incorporation observed in intact cells is due to an effect at a locus other than the DNA and RNA polymerase reactions.     

L-type calcium current of isolated rat cardiac myocytes in experimental uraemia.

BACKGROUND: End-stage renal failure is associated with a low-output cardiomyopathy, left ventricular hypertrophy and increased QTc dispersion. Cardiac dysfunction is prevalent in patients at the beginning of dialysis and is an important predictor of mortality. Ca(2+) influx through voltage-gated L-type Ca(2+) channels plays a key role in the excitation-contraction coupling of cardiac myocytes. The purpose of this study was to examine the effect of subtotal nephrectomy (SNx) in the rat on both cardiac L-type Ca(2+) currents and action potential duration. METHODS: Wistar rats underwent two-stage SNx; control rats (C) underwent bilateral renal decapsulation. Animals were sacrificed after 8 weeks, and ventricular myocytes were isolated. SNx rats showed a 2-fold increase in plasma urea and creatinine compared with C rats. Whole-cell patch clamp techniques were used to examine L-type Ca(2+) channel currents in isolated cardiac myocytes at 37 degrees C. In separate experiments, the epicardial monophasic action potentials of isolated perfused whole hearts from C and SNx rats were recorded. RESULTS: The amplitude and current-voltage relationships of the L-type Ca(2+) current were not significantly different in myocytes from C (n=11) and SNx (n=8) rats. However, the rate of inactivation of the Ca(2+) current was increased by approximately 15-25% (P<0. 05) in myocytes from SNx rats. The action potential duration (APD(33)) at the apex of the left ventricle was approximately 20% shorter (P<0.01) in hearts from SNx rats as compared with controls. CONCLUSIONS: Renal failure is associated with rapid inactivation of cardiac ventricular myocyte L-type Ca(2+) currents, which may reduce Ca(2+) influx and contribute to shortening of the action potential duration.     

Infiltration of tumor-reactive transforming growth factor-beta insensitive CD8+ T cells into the tumor parenchyma is associated with apoptosis and rejection of tumor cells

BACKGROUND: TGF-beta is a potent immunosuppressant. High levels of TGF-beta produced by cancer cells have a negative inhibition effect on surrounding host immune cells and leads to evasion of the host immune surveillance and tumor progression. In the present study, we report a distinct ability of tumor reactive, TGF-beta-insensitive CD8+ T cells to infiltrate into established tumors, secrete relevant cytokines, and induce apoptosis of tumor cells. METHODS: CD8+ T cells were isolated from the spleens of C57BL/6 mice, which were primed with irradiated mouse prostate cancer cells, the TRAMP-C2 cells. After ex vivo expansion, these tumor reactive CD8+ cells were rendered TGF-beta-insensitive by infection with a retroviral (MSCV)-mediated dominant negative TGF-beta type II receptor (TbetaRIIDN). Control CD8+ cells consist of those transfected with the GFP-only empty vector and na?ve CD8+ T cells. Recipient mice were challenged with a single injection of TRAMP-C2 cells 21 days before adoptive transfer of CD8+ T cells was performed. Forty days after the adoptive transfer, all animals were sacrificed. The presence of pulmonary metastases was evaluated pathologically. Serial slides of malignant tissues were used for immunofluorescent staining for different kinds of immune cell infiltration, cytokines, and apoptosis analysis. RESULTS: Pulmonary metastases were either eliminated or significantly reduced in the group receiving adoptive transfer of tumor-reactive TGF-beta-insensitive CD8+ T cells (3 out of 12) when compared to GFP controls (9 out of 12), and na?ve CD8+ T cells (12 out of 12). Results of immunofluorescent studies demonstrated that only tumor-reactive TGF-beta-insensitive CD8+ T cells were able to infiltrate into the tumor and mediate apoptosis when compared to CD4+ T cells, NK cells, and B cells. A large amount of cytokines such as perforin, nitric oxide, IFN-gamma, IL-2, TNF-alpha were secreted in tumor tissue treated with tumor-reactive TGF-beta-insensitive CD8+ T cells. No immune cells infiltration and cytokine secretion were detected in tumor tissues treated with na?ve T cells and GFP controls. CONCLUSIONS: Our results demonstrate the mechanism of anti-tumor effect of tumor-reactive TGF-beta-insensitive CD8+ T cells that adoptive transfer of these CD8+ T cells resulted in infiltration of these immune cells into the tumor parenchyma, secretion of relevant cytokines, and induction of apoptosis in tumor cells. These results support the concept that tumor-reactive TGF-beta-insensitive CD8+ T cells may prove beneficial in the treatment of advanced cancer patients.     

Role of cytosolic phospholipase A2 in cytokine-stimulated prostaglandin release by human gallbladder cells

Eicosanoids are involved in gallbladder inflammation, epithelial water transport, and mucous secretion. Phospholipase A, enzymes liberate arachidonic acid from membrane phosphohpids for the synthesis of eicosanoids. The purpose of this study was to determine the effect of selective cytoplasmic and secretory phospholipase A; inhibitors on basal and stimulated arachidonic acid and prostaglandin F., release in gallbladder cells. Western immunoblotting was employed to evaluate both cytosolic and secretory phospholipase A₂ enzymes in human gallbladder cells. Cells were incubated tor 22 hours with H-labelcd arachidonic acid. Arachidonic acid and prostaglandin E₂ release was then measured in the supernate after 2 hours of exposure to human interleukin-lβ, alone or after pretreatment for I hour with the inhibitors. Unstimulated gallbladder cells express both H5 kDa cytosolic and 14 kDa secretory phospholipase A;. The 85 kDa phospholipase A₂ was induced by interleukin-lβ, whereas there was no apparent change in secretory phospholipase A. enzyme concentrations. Both the secretory phospholipase A. inhibitor p-bromophenylacyl bromide and the cytosolic phospholipase A, inhibitor arachidonyl trirluorometlvyl ketone decreased basal and interleukin-1 β-stunulated arachidonic acid release. In contrast, only inhibition of cytosolic phospholipase A: led to a decrease in interleukin-1 β-stimulated prostaglandin E₂: release. Basal and intcrlcukin-lβ—stimulated arachidonic acid release appears to be the result of the activity ol both cytosolic and secretory phospholipase A₂. Interleukin-Iβ—stimulated prostaglandin E₂ release appears to he dependent on the activity of cytosolic phospholipase A₂ Supported by grant DK 27695 from the United States Public Health Service. Presented in part at the American Gastroenterologie Association Research Forum. Orlando, Fla., May 18. 1999.     

Effect of the 21-aminosteroid on nuclear factor-kappa B activation of Kupffer cells in endotoxin shock

BACKGROUND: The 21-aminosteroid (U-74389G) is a nonglucocorticoid steroid that was synthesized to inhibit lipid peroxidation without the glucocorticoid activity. We recently demonstrated that the 21-aminosteroid administered to endotoxin shock mice reduces liver injury and improves the survival rate of mice through inhibition of nuclear factor-kappa B activation in the liver. The study was undertaken to determine whether the 21-aminosteroid could suppress pro-inflammatory gene up-regulation through inhibition of nuclear factor-kappa B activation in Kupffer cells. METHODS: Kupffer cells were isolated from rats by collagenase perfusion followed by pronase digestion. After a lipopolysaccharide addition, each assay was performed for tumor necrosis factor-alpha, interleukin-6, tumor necrosis factor-alpha messenger RNA, nuclear factor-kappa B, and I kappa B proteins. RESULTS: After the lipopolysaccharide addition, Kupffer cells released both tumor necrosis factor-alpha and interleukin-6. The 21-aminosteroid treatment suppressed the release of tumor necrosis factor-alpha in a dose-dependent manner. The 21-aminosteroid also inhibited the increase of tumor necrosis factor-alpha messenger RNA expression and nuclear factor-kappa B activation in Kupffer cells 1 hour and 30 minutes, respectively, after lipopolysaccharide addition. Furthermore, the 21-aminosteroid treatment suppressed the degradation of I kappa B proteins in lipopolysaccharide-stimulated Kupffer cells. CONCLUSIONS: These results suggest that the 21-aminosteroid inhibits release of the tumor necrosis factor-alpha and interleukin-6 from lipopolysaccharide-stimulated Kupffer cells by inhibiting nuclear factor-kappa B activation. This is accomplished by inhibiting I kappa B degradation in endotoxin shock and this may prove useful for the treatment of endotoxin shock.     

人精子RNA的提取及含量分析

目的建立可靠的提取人精子RNA的方法,分析其含量并用于检测基因mRNA。方法9例正常精液标本液化后,经Percoll纯化,用体细胞裂解液(含0.1%十二烷基硫酸钠和0.5%Triton X-100的水溶液)于0℃处理15 min去除精子以外的细胞。用RNeasy Kit提取精子RNA,微量核酸测定仪测定RNA量。RNA用于逆转录-聚合酶链反应(RT-PCR),检测β-Actin、精子特异性阳离子通道2(CatSper2)、鱼精蛋白2(Protamine-2)mRNA,同时,检测c-Kit、CD4、上皮细胞钙粘蛋白(E-Cad-herin)mRNA,分别排除生精细胞、白细胞和上皮细胞的污染。结果体细胞裂解液于0℃处理15 min能去除精子以外的细胞,使精子RNA提取量提高(2.2~4.9倍)。9例正常精液标本RNA量为(233.5±75.3)ng/106精子。所有标本RNA用RT-PCR,均成功扩增β-Actin、CatSper2、Protamine-2,但扩增c-Kit、CD4、E-Cadherin未见目的条带。结论人精子中含微量RNA,本提取方法能提取人精子中微量RNA,且避免其他细胞污染,可供人精子RNA研究和临床检测选用。     

雷公藤甲素预处理诱导Tregs细胞减轻小鼠肝脏缺血再灌注损伤的实验研究

目的 探讨雷公藤甲素(TPT)预处理减轻小鼠肝脏缺血再灌注损伤的作用及其机制.方法 将C57BL/6小鼠随机分为4组(15只/组):假手术对照组;假手术雷公藤甲素组;实验对照组;雷公藤甲素实验组.两个雷公藤甲素组小鼠术前1周每天给予雷公藤甲素0.1 mg/kg腹腔注射,术前1h加用一次,而两对照组同期仅给予等体积无菌生理盐水腹腔注射.肝脏缺血90 min再灌注24 h后分别采集各组小鼠的血液和肝组织,检测血清丙氨酸转移酶(ALT)、天冬氨酸转移酶(AST)水平.以及肝脏组织丙二醛(MDA)和超氧化物歧化酶(SOD)含量.光镜下观察肝组织的病理学变化.采用流式细胞术检测肝组织中CD4+CD25+Foxp3+T淋巴细胞占CD4+T细胞的百分比,采用实时聚合酶链反应检测肝组织中Foxp3 mRNA的表达.采用酶联免疫吸附试验检测血清中IL-10、IL-6、IL-1β和TNF-α细胞因子含量.结果 雷公藤甲素实验组和实验对照组小鼠血清ALT和AST明显升高,且雷公藤甲素实验组水平低于实验对照组(P＜0.05).假手术雷公藤甲素组和雷公藤甲素实验组与相应假手术和实验对照组相比MDA含量降低,SOD活性升高(P＜0.05).两假手术组肝组织结构正常,实验对照组可见明显的肝组织片状坏死,雷公藤甲素实验组肝小叶结构基本正常.假手术对照组、假手术雷公藤甲素组、实验对照组和雷公藤甲素实验组CD4+CD25+Foxp3+T淋巴细胞占CD4+T细胞的百分比分别为(7.55±1.87)%、(12.59±3.87)%、(7.85±1.07)%和(12.02±3.16)%.假手术雷公藤甲素组和雷公藤甲素实验组Foxp3 mRNA相对表达量高于相应的对照组(P＜0.05).雷公藤甲素实验组较实验对照组相比有升高血清IL-10,降低IL-6、IL-1β和TNF-α细胞因子的含量的作用.结论 雷公藤甲素可减轻小鼠肝脏缺血再灌注损伤,其机制可能与雷公藤甲素诱导上调体内CD4+CD25+Foxp3+调节性T淋巴细胞比例及增加IL-10分泌,抑制IL-6、IL-1p和TNF-α炎症细胞因子有关.

Abstract：

Objective To investigate the effect and related mechanism of triptolide pretreatment to prevent from ischemia/reperfusion (I/R) injury in mice liver. Methods Sixty male C57BL/6 mouse were randomized into four groups (15/group): A:sham group with saline , B: sham group with triptolide, C: saline I/R group, D: triptolide I/R group. The mice were pretreated with either saline or triptolide (0. 1 mg/kg/d) through intraperitoneal (ip) injection for one week. The mouse partial liver model of I/R injury was established, and samples were collected at 24 h after the I/R injury. Results Serum ALT and AST levels were significantly decreased and histological damage was significantly alleviated in the triptolide I/R group as compared with the saline I/R group (P＜0.05), the concentration of MDA in the triptolide groups was significantly decreased, while SOD activity was significantly increased compared with that of the saline I/R group (P＜0.05). The percentages of CD4+ CD25+ regulatory T cells (Tregs) cells among CD4+ T cells in groups A, B, C, and D were(7. 55 ± 1.87)%, (12. 59±3. 87)%,(7. 85±1.07)%, and(12. 02±3. 16)% in liver tissue, respectively. The expression levels of Foxp3 mRNA were significantly higher in the triptolide I/R group than those of saline I/R group (P＜0. 05). ELISA showed that triptolide could significantly inhibit the levels of IL-6, IL-Iβ and TNF-αand promoted the level of IL-10 in the serum (P＜0.05). Conclusion Pretreatment with triptolide could effectively prevent from liver I/R injury, which may be related to the induction of Treg cells by triptolide, the increase in the level of IL-10 in serum, and the inhibition of IL-6, IL-1β and TNF-α production in serum.