FK506抑制脊髓挫伤后诱导型一氧化氮合酶表达的实验研究

目的观察大鼠脊髓挫伤后早期应用FK506对诱导型一氧化氮合酶(iNOS)表达的抑制作用。方法45只成年雄性大鼠随机分为假手术组、对照组和治疗组。治疗组在脊髓挫伤后5 min一次性经尾静脉注射FK506(0.3mg/kg),其余两组以相同方法给予0.9%生理盐水。伤后3,7,14,21 d采用BBB评分法进行后肢运动功能评价,应用逆转录聚合酶链反应(RT-PCR)和免疫组织化学染色检测iNOS的mRNA和蛋白质的表达,同时行脊髓组织尼氏染色病理学观察。结果治疗组病理学观察和行为学评分明显优于对照组(P<0.05,P<0.01);iNOS的mRNA和蛋白质的表达均于伤后7 d达高峰,两者表达在治疗组明显低于对照组(P<0.05,P<0.01)。结论FK506能抑制大鼠脊髓挫伤后iNOS表达,减轻继发性损害,从而改善脊髓损伤后的功能恢复。     

FK228对HepG2细胞NF-κB活化及炎症因子转录的影响

目的:研究FK228对TNF-α诱导的人肝癌细胞HepG2核转录因子κB(nuclear factor-κB,NF-κB)活化及炎症因子IL-6、IL-8转录的影响。方法:培养的HepG2细胞分为对照组、TNF-α刺激组和FK228干预组。分别用TNF-α刺激和FK228+TNF-α共同作用,免疫印迹(Western blot)法分析细胞核中NF-κBp65及其细胞浆中抑制因子IκBα的表达;RT-PCR对炎症因子IL-6、IL-8 mRNA作半定量分析。结果:FK228(4～32μg·L~(-1))干预组与TNF-α刺激组比较,细胞核内NF-κB显著减少(P<0.01);FK228(8～32μg·L~(-1))减少胞浆中IκBα的降解且各组之间差异有统计学意义(P<0.01);FK228降低TNF-α诱导的IL-6、IL-8 mRNA表达,FK228干预组与TNF-α刺激组相比,差异具统计学意义(P<0.01)。结论:FK228减少胞浆中IκBα降解、阻碍NF-κB的过度活化可能是降低炎症因子释放、发挥抗炎作用的重要机制。     

Roles of the jejunum and ileum in the first-pass effect as absorptive barriers for orally administered tacrolimus

BACKGROUND: The immunosuppressant tacrolimus shows poor and variable bioavailability following oral administration in clinical use. Recently, the hepatic and intestinal metabolisms, or first-pass effect, of tacrolimus have been suggested to be responsible for its bioavailability. In the present study, we investigated the respective contribution of the jejunum and ileum to the first-pass effect of tacrolimus in rats. METHODS: The metabolism of tacrolimus in everted sacs of the duodenum, jejunum, and ileum was examined. Tacrolimus was administered intravenously or intraintestinally to sham-operated, jejunum-resected, or ileum-resected rats. Blood samples were collected over a 240-min period, and whole-blood tacrolimus concentrations were measured by semiautomated microparticle enzyme immunoassay. The pharmacokinetic parameters of tacrolimus in each group were estimated. RESULTS: The metabolic activity of tacrolimus appeared to be the highest in the everted sacs of the duodenum. The bioavailability of tacrolimus in the jejunum- or ileum-resected rats was higher than that in sham-operated controls. On the other hand, the time to peak concentration in the jejunum-resected rats was about twofold slower than those in ileum-resected and sham-operated rats. CONCLUSIONS: These results suggested that the first-pass effect of tacrolimus in the small intestine shows regional differences and the extraction of tacrolimus in the small intestine consists of the amount of extraction in the jejunum and ileum. In addition, the ileum rather than the jejunum as a graft of segmental small bowel transplantation would be useful to avoid the adverse effects of tacrolimus.     

肾移植术后肝功能异常患者用普乐可复替换环孢素A疗效的初步观察

目的观察肾移植术后应用环孢素A（CsA）导致肝功能损害的患者，更换普乐可复（FK506）对肝功能损害治疗的有效性和安全性。方法选择18例肾移植术后应用CsA出现肝功能异常的患者，以FK506替换CsA，FK506初始剂量及维持剂量以患者体重、移植后时间、病情及FK506血药浓度进行相应调整，同时保肝治疗。结果将CsA替换成FK506治疗2-8周后，患者肝功能指标（血清ALT、D-BIL及I-BIL）呈明显下降趋势。8-12周后，14例患者肝功能恢复正常，4例接近正常，替换前后比较差异有显著性，P〈0．05。肾功能（血清Cr、BUN）换药前后比较差异无显著性，P〉0．05。继续随访3-6个月，肝功能、肾功能全部维持正常。结论对CsA引起肝功能损害的肾移植患者应用FK506替换治疗是安全有效的。     

Effects of MK-801, dantrolene, and FK506 on convulsive seizures and brain nitric oxide production in seizure-susceptible EL mice

To clarify the role of nitric oxide (NO) in the pathogenesis of seizures in susceptible EL mice, we investigated effects of three drugs potentially related to NO production, MK-801, dantrolene, and FK506, on convulsive seizures and brain NO metabolites (NOx). MK-801 or dantrolene, but not FK506, suppressed convulsive seizures in EL mice; only MK-801 reduced NOx in the brain. Our results suggested involvement of the N-methyl-D-aspartate receptor-channel complex and intracellular calcium mobilization, but not calcineurin, in the convulsions of EL mice.     

Effect of FK506 on Expression of Hepatocyte Growth Factor in Murine Spinal Cord Following Peripheral Nerve Injury

This study is to investigate the effect of FK506 on expression of hepatocyte growth factor （HGF） in rats＇ spinal cord following peripheral nerve injury and to elucidate the mechanisms for neuroprotective property of FK506. Fifty male rats were randomly divided into normal group, injury group and treatment group. Models of peripheral nerve injury were established by bilateral transection of sciatic nerve 0.5 cm distal to piriform muscle. Then the treatment group received subcutaneous injection of FK506 （1 mg/kg） at the back of neck, while the injury group was given 0.9% saline. The L4-6 spinal cords were harvested at various time points after the surgery. Western blotting and immunofluorescent staining were used to detect the level and position of HGF in spinal cord. Immunofluorescent staining showed that HGF-positive neurons were located in anterior horn, intermediate zone and posterior horn of gray matter in normal spinal cord. Western blotting revealed that there was no significant difference in the expressions of HGF between the injury group and the normal group, while the expression of HGF was significantly higher in the treatment group than in the injury group 7 and 14 days after surgery. It is suggested that peripheral nerve injury does not result in up-regulation of the expression of HGF in spinal cord, while FK506 may induce high expression of endogenous HGF after injury thereby protecting neurons and promoting axonal outgrowth.     

Post-transplant epididymitis and orchitis following Listeria monocytogenes septicaemia

We report the occurrence of epididymitis and orchitis 1 week after the onset of Listeriosis in an 11-month-old boy receiving an orthotopic liver transplantation for biliary atresia. Immunologic implications of Listeria monocytogenes-induced testicular inflammation are discussed, and the potential role of immunosuppression with tacrolimus is also discussed.     

Population pharmacokinetics of tacrolimus in Asian paediatric liver transplant patients

AIMS: The purpose of this study was to describe the population pharmacokinetics of intravenous and oral tacrolimus (FK506) in 20 Asian paediatric patients, aged 1-14 years, following liver transplantation and to identify possible relationships between clinical covariates and population parameter estimates. METHODS: Details of drug dosage histories, sampling times and concentrations were collected retrospectively from routine therapeutic drug monitoring data accumulated for at least 4 days after surgery. Before analysis, patients were randomly allocated to either the population data set (n = 16) or a validation data set (n = 4). The population data set was comprised of 771 concentration measurements of patients admitted over the last 3 years. Population modelling using the nonlinear mixed-effects model (NONMEM) program was performed on the population data set, using a one-compartment model with first-order absorption and elimination. Population average parameter estimates of clearance (CL), volume of distribution (V) and oral bioavailability (F) were sought; a number of clinical and demographic variables were tested for their influence on these parameters. RESULTS: The final optimal population models related clearance to age, volume of distribution to body surface area and bioavailability to body weight and total bilirubin concentration. Predictive performance of this model evaluated using the validation data set, which comprised 86 concentrations, showed insignificant bias between observed and model-predicted blood tacrolimus concentrations. A final analysis performed in all 20 patients identified the following relationships: CL (l h-1) = 1.46 *[1 + 0. 339 * (AGE (years) -2.25)]; V (l) = 39.1 *[1 + 4.57 * (BSA (m2)-0. 49)]; F = 0.197 *[1 + 0.0887 * (WT (kg) -11.4)] and F = 0.197 *[1 + 0.0887 * (WT (kg) -11.4)] * [1.61], if the total bilirubin > or = 200 micromol l-1. The interpatient variabilities (CV%) in CL, V and F were 33.5%, 33.0% and 24.1%, respectively. The intrapatient variability (s.d.) among observed and model-predicted blood concentrations was 5.79 ng ml-1. CONCLUSIONS: In this study, the estimates of the pharmacokinetic parameters of tacrolimus agreed with those obtained from conventional pharmacokinetic studies. It also identified significant relationships in Asian paediatric liver transplant patients between the pharmacokinetics of tacrolimus and developmental characteristics of the patients.     

FK506预处理下骨髓移植诱导同种异体小鼠皮肤移植耐受的实验研究

目的探讨短期大剂量FK506作为宏嵌合诱导供体特异性耐受中,骨髓移植前对受体预处理方法的可行性及临床实用性. 方法 100只雄性C57BL/6和60只雌性BALB/C小鼠分别作为皮肤移植的供体和受体,雄性ICR小鼠15只作为无关第三品系用以检测移植耐受状态的特异性.将60只受体小鼠随机分为5组,即无处理对照组、单纯FK506组、单纯骨髓细胞移植(BMT)组、实验组(FK506 BMT)和无关供体对照组,每组12只.FK506诱导及维持方案是皮肤移植前对受体小鼠先给予大剂量FK506腹腔注射(3 mg/kg×2 d),移植当天尾静脉输注2×107个骨髓细胞,再以小剂量FK506(0.5 mg/kg×7 d)短期维持治疗.观察皮肤移植存活时间、对第三方皮肤的排斥反应及对供体鼠的单向混合淋巴细胞反应,并用多聚酶链式反应(PCR)检测嵌合体的形成. 结果常规剂量的骨髓输注或短期FK506治疗并不能延长移植物的存活时间,也没有宏嵌合形成.实验组皮肤移植物存活时间(24.0±1.5)d比无处理对照组(9.6±1.1)d、单纯FK506组(10.5±1.6)d、单纯骨髓细胞移植组(10.3±1.5)d、无关供体对照组(9.8±1.1)d明显延长(P<0.05).混合淋巴细胞反应实验组供者特异性抑制率80.55%±14.10%明显高于单纯FK506组38.65%±12.43%及单纯骨髓细胞移植组35.41%±8.99%(P<0.05),实验组宏嵌合呈阳性. 结论采用短期大剂量FK506这一温和的非照射预处理方法,可获得一定程度的免疫耐受,延长移植物存活.移植前输注供体骨髓细胞能够促进宏嵌合的形成及移植物的存活.     

利用神经再生室观察FK506促进神经再生的实验研究

目的探讨免疫抑制剂FK506促神经再生的作用及药物应用方法。方法将雄性SD大鼠60只随机分成3组,每组20只,切断双侧坐骨神经制成坐骨神经再生室模型。A组在再生室内注入生理盐水;B组在再生室内注入盐水,颈后皮下注射FK5061mg／kg,连续14d;C组在再生室内注入1μg／mlFK506。观察神经损伤局部的免疫反应、检测腓肠肌湿重、组织形态学及图像分析、电生理学。结果B、C组大鼠神经损伤局部淋巴细胞浸润程度较A组轻微。6周时大鼠腓肠肌湿重为：A组平均579mg,B组平均725mg,C组平均761mg,B、C组大鼠腓肠肌湿重明显优于A组;组织形态学观察与图像分析显示,有髓神经纤维总数为：A组平均720根,B组平均778根,C组平均772根,在有髓神经纤维密度、平均轴突直径、髓鞘厚度等指标中,B组结果明显优于A组。结论（1）大鼠全身应用FK506后具有神经保护和神经营养作用,可加快神经功能的恢复。（2）局部应用FK506对早期损伤神经有一定的保护作用。