二至丸保肝有效部位群对体外肝细胞损伤的保护作用

目的 研究二至丸保肝有效部位群(50％乙醇部位)(EFEP)对体外肝细胞损伤的保护作用及机理.方法 培养L-O2型肝细胞,采用四氯化碳(CCl4)和过氧化氢(H2O2)体外诱导肝细胞损伤,检测培养上清液中AST和ALT水平,测定上清液中丙二醛(MDA)的含量、过氧化物岐化酶(SOD)及谷胱甘肽过氧化物酶(GSH-Px)活性,MTT法检测细胞存活和增殖活性.结果 EFEP0.32-40 μg/ml明显降低由CCl4所致肝细胞培养上清液中AST和ALT水平和MDA含量的升高,也显著提高由CCl4所致肝细胞存活率和SOD活力及GSH-Px活性的降低.EFEP 0.32-40 μg/ml使H2O2升高的肝细胞培养上清液中AST和ALT水平及MDA含量明显降低,还显著提高由H2O2降低的肝细胞存活率和SOD活力及GSH-Px活性.结论 EFEP对体外肝细胞损伤有较强的保护作用.该作用可能与其抗氧化作用有关.     

胶原夹心培养大鼠肝细胞及其细胞色素P450酶活性的测定

目的　自制大鼠尾腱Ⅰ型胶原培养原代大鼠肝细胞 ,测定肝细胞中细胞色素P450 (cytochromeP450 ,CYP)酶活性。方法　制备无菌大鼠尾腱Ⅰ型胶原 ,比较单层胶原铺底法 (collagencoated ,CC)及胶原夹心法 (collagensandwichsys tem ,CSS)培养大鼠肝细胞的生长及功能维持情况。CSS法培养肝细胞 ,分别加入泼尼松龙 (10 0 μmol·L- 1,3d)、尼莫地平 (50 μmol·L- 1,2d)和利福平 (50 μmol·L- 1,2d) ,测定CYP1A、CYP2E1及CYP3A酶活性。结果　CSS法培养 6d后 ,肝细胞生长良好。CC法培养 3d后细胞开始脱落 ,此后持续增多 ;6d后 ,培养上清液中ALT、AST与LDH活性升高 ,均高于同期CSS法培养细胞上清液中的水平。加入经CYP3A代谢药物 ,CSS培养肝细胞CYP1A活性无明显改变 ;尼莫地平使CYP3A活性升高 3 3 % ,而CYP2E1活性下降 45% (P <0 0 5) ;利福平使CYP3A活性升高为对照组的1 94倍 (P <0 0 5) ,对CYP2E1活性无作用。结论　同为CYP3A底物 ,泼尼松龙、尼莫地平和利福平对CYP亚型的影响不同 ,但不改变肝细胞CYP1A对致癌物的活化。CSS培养法可作为体外模型用于药物代谢研究     

高糖环境下HGF对肾小球系膜细胞增殖及TGF-β1的影响

目的研究高糖环境下大鼠肾小球系膜细胞(RMC)的增殖、转化生长因子β1(TGF-β1)的分泌、以及肝细胞生长因子(HGF)的干预作用。方法①将RMC分为3组:正常对照组;高糖组;高糖+HGF组(25.0mmol/L葡萄糖,50ng/mlHGF)。分别培养不同时间(12,24,48,72,96h)。运用MTT法测定细胞的增殖情况。②将RMC分为3组:正常对照组;高糖组;甘露醇对照组:(20.0mmol/L甘露醇)。分别于培养的12、24、48、96h收集细胞及上清夜,用ELISA法来检测TGF-β1分泌量。③将RMC分为:正常对照组;高糖组;高糖+HGF组(HGF浓度分别为25、50、100、200ng/ml)。分别培养48h后,用ELISA法测定此时TGF-β1分泌情况。以上各组正常组中葡萄糖浓度5.5mmol/L,高糖浓度25.0mmol/L。结果①25.0mmol/L高糖在24h促进RMC增殖,肝细胞生长因子(HGF)可以抑制细胞增殖。在48,72和96h高糖抑制细胞增殖。HGF对抗高糖对细胞增殖的抑制作用;而且呈时间依赖性。②高糖促进TGF-β1分泌,HGF可以抑制TGF-β1的分泌,且呈剂量依赖性。结论高糖刺激肾小球系膜细胞TGF-β1出现稳定高表达,而给予外源性的HGF后,系膜细胞TGF-β1的分泌减少,而且呈时间依赖性。     

促肝细胞生长素对体外培养成人肝细胞增殖和细胞周期的影响

目的 观察促肝细胞生长素(PHGF)在成人肝细胞(HH)增殖和细胞周期中的作用.方法 体外培养一定时间后,HH分成空白对照组和5个PHGF剂量(10、20、40、80、160)μg/ml干预组,采用台盼蓝染色,计数CCK-8检测细胞增殖,流式细胞术检测细胞周期.结果 PHGF对HH增殖有明显促进作用,PHGF 20和40 μg/ml两组HH增殖明显大于对照组(P＜0.05);与对照组相比,PHGF作用48 h后,20和40μg/ml两组G0/G1期细胞比例减少,S期C2/M期细胞比例增加(P＜0.05).结论 在一定剂量范围内,PHGF促进HH增生,其可能机制是通过促进DNA合成,增加进入S期细胞数目实现的.     

玉郎伞多糖对四氯化碳诱导大鼠原代肝细胞损伤的保护作用

目的:研究玉郎伞多糖(YLS)对大鼠原代肝细胞损伤的保护作用及其机制。方法:采用IV型胶原酶灌流法分离大鼠肝细胞进行原代培养,用四氯化碳(CCl4)体外诱导肝细胞损伤,检测培养上清液中天门冬氨酸转换酶(AST)和丙氨酸氨基转换酶(ALT)水平,测定肝细胞中丙二醛(MDA)和谷胱甘肽(GSH)含量,MTT法检测细胞存活和增殖活性。结果:YLS(0.125~1.000g.L-1)可明显降低由CCl4升高的肝细胞培养上清液中AST和ALT水平及肝细胞MDA含量,还可提高CCl4降低的肝细胞存活率和GSH含量。结论:提示YLS对大鼠原代培养肝细胞损伤有直接保护作用,该作用可能与其抗氧化作用有关。     

低氧下肝细胞生长因子对胃癌细胞侵袭的影响

目的探讨低氧条件下,肝细胞生长因子(HGF)对胃癌细胞株侵袭,迁移的影响及其机制。方法将细胞分为常氧组和低氧组,分别给予不同浓度的HGF培养48h,用划痕法测定细胞的迁移能力,Boyden小室体外侵袭实验测定细胞穿透基底膜能力,细胞免疫组化检测各组细胞乙酰肝素酶蛋白(HPSE)的表达。结果低氧组的细胞迁移力和细胞侵袭力明显高于常氧组,在HGF作用下尤为显著(P<0.05),HPSE蛋白的表达在低氧和HGF条件下显著增强。结论低氧可显著提高胃癌细胞HPSE蛋白的表达及其细胞的侵袭力,其侵袭力的增加,可能与HGF作用有密切关系     

珠蚌多糖对四氯化碳诱导肝细胞损伤的保护作用

目的 研究珠蚌多糖(HCP)对肝细胞损伤的保护作用及其机制.方法 培养L-02型肝细胞,用四氯化碳(CCL)体外诱导肝细胞损伤,检测培养上清液中天门冬氨酸转挟酶(AST)和丙氨酸氨基转换酶(ALT)水平,测定上清液中丙二醛(MDA)的含量扣过氧化物岐化酶(SOD)活力,MTT法检测细胞存活和增殖活性.结果 珠蚌多糖(25,250及1000μg·L-1)剂量组均可明显降低由CCl4升高的肝细胞培养上清波中AST争ALT水平及MDA含量,还可提高CCl4降低的肝细胞存活率和SOD活力.结论 提示珠蚌多糖对肝细胞损伤有直接保护作用,该作用可能与其抗氧化作用有关.     

丹参酮ⅡA对损伤肝细胞的保护作用及活化肝星状细胞的抑制作用

目的探索丹参酮ⅡA对体外培养肝细胞株HL-7702的安全使用剂量并观察丹参酮ⅡA对肿瘤坏死因子α(TNF-α)和过氧化氢(H2O2)所致体外培养肝细胞损伤的保护作用;同时探讨丹参酮ⅡA对活化肝星状细胞增殖的抑制作用。方法体外培养人肝细胞株HL-7702,加入不同浓度的丹参酮ⅡA,通过MTT比色法检测肝细胞存活率并检测培养上清液中丙氨酸转氨酶(ALT)和乳酸脱氢酶(LDH)含量的变化。建立TNF-α和H2O2所致肝细胞损伤模型,测定培养上清液中的ALT和LDH含量,同时用MTT比色法检测肝细胞存活率。体外培养大鼠肝星状细胞株HSC-T6,加入不同浓度的丹参酮ⅡA,通过MTT比色法检测肝星状细胞存活率。结果①丹参酮ⅡA在一定的剂量范围内对肝细胞无细胞毒性,超过该剂量时,其细胞毒性表现为细胞存活率下降和肝细胞合成分泌的ALT、LDH水平增高。②丹参酮ⅡA可改善TNF-α所致肝细胞存活率下降及ALT、LDH水平的增高。③丹参酮ⅡA可改善H2O2所致肝细胞存活率的下降。④丹参酮ⅡA可抑制活化肝星状细胞的增殖。结论①丹参酮ⅡA对于体外培养肝细胞株(HL-7702)的安全剂量范围为1～2μg/ml。②丹参酮ⅡA在安全剂量范围内能改善TNF-α和H2O2所致体外培养人肝细胞株的损伤。③丹参酮ⅡA在25～100μg/ml的剂量范围内可以有效抑制活化肝星状细胞的增殖。     

大鼠肝细胞分离及体外损伤模型建立

目的:分离大鼠肝细胞,建立体外大鼠肝细胞损伤模型.方法:改进Seglen胶原酶(IV型)原位灌注分离大鼠肝细胞,培养液中加入不同浓度D-氨基半乳糖培养24 h,于培养1、3、6、12、24 h取上清测定ALT(丙氨酸氨基转移酶)、AST(天门冬氨酸转移酶)、LDH(乳酸盐脱氢酶),同步测定肝细胞的细胞增殖活性(MTT)反应.结果:平均肝细胞产量(8.92±0.47)×108,Trypan blue拒染实验细胞活性率96.23%±2.41%,培养体系中加入D-氨基半乳糖后,部分肝细胞胞膜破损,随剂量增加及时间延长而逐渐加重;各剂量组随时间延长,培养上清液中生化指标水平逐渐升高,而MTT反应水平逐渐下降,以3 h与6 h变化最为明显;各时间点生化指标及MTT反应变化随剂量增加呈现相同趋势.结论:该方法可获得高产量高活性大鼠肝细胞;D-氨基半乳糖可成功诱导大鼠肝细胞体外损伤模型.     

甜菜红苷对人结肠癌HT29细胞凋亡的影响

目的:研究甜菜红苷对人结肠癌HT29细胞凋亡的影响。方法:体外传代培养HT29细胞。以不同质量浓度[0(空白对照)、0.5、1、1.5、2、3 mg/ml]的甜菜红苷培养细胞24 h,以1.5 mg/ml甜菜红苷培养细胞不同时间[0(空白对照)、1、3、6、12、24 h]后,采用MTT法测定细胞活力并计算抑制率;以0(空白对照)、1、1.5、2 mg/ml甜菜红苷培养细胞24 h后,采用流式细胞仪测定细胞凋亡率,测定含半胱氨酸的天冬氨酸蛋白水解酶3(Caspase-3)、Caspase-9的活性,采用实时荧光聚合酶链反应(RT-PCR)与Western blot法测定Bcl-2、Bax m RNA与蛋白的表达。结果:与空白对照比较,0.5、1、1.5、2、3 mg/ml甜菜红苷培养细胞24 h后,1.5 mg/ml甜菜红苷培养细胞1、3、6、12、24 h后,细胞抑制率升高(P<0.01)。与空白对照比较,1、1.5、2 mg/ml甜菜红苷培养细胞24 h后,细胞凋亡率升高,Caspase-3、Caspase-9活性增强,Bcl-2 m RNA与蛋白表达减弱、Bax m RNA与蛋白表达增强(P<0.01)。结论:甜菜红苷可诱导HT29细胞凋亡,其机制可能与上调Caspase-3、Caspase-9活性和Bax m RNA与蛋白表达,下调Bcl-2 m RNA与蛋白表达有关。     

Reinforcement of antitumor effect of Cordyceps sinensis by 2'-deoxycoformycin, an adenosine deaminase inhibitor

In this study, an attempt was made to elucidate the combined effect of 2'-deoxycoformycin (DCF), an adenosine deaminase inhibitor, with a water extract of Cordyceps sinensis (WECS), on the growth curves of mouse melanoma and lung carcinoma cells. Sub-confluent cells were harvested with an EDTA trypsin solution, and resuspended to appropriate concentrations in DMEM containing 10% fetal bovine serum. Using 1x10(5) cells/2 ml in each well of a 12-well culture plate, cells were incubated for 24, 48 and 72 h in the presence of WECS alone, or WECS plus DCF in a CO2 incubator at 37 degrees C. Duplicate samples of viable cells were enumerated with a Coulter counter. The antitumor effect of WECS on the growth curves of tumor cell lines increased over 3-fold in combination with DCF. These results suggest that DCF has a remarkable reinforcement effect on the antitumor activity of WECS. DCF is a potent adjuvant for WECS.     

姜黄素对热打击血管内皮细胞损伤的保护作用

目的:研究姜黄素对热打击导致的人脐静脉内皮细胞(HUVECs)损伤的影响。方法:建立HUVECs热打击模型,对照组细胞置于标准37℃、5%CO2细胞培养箱培养,热打击组细胞于43℃细胞培养箱中热打击2 h,热打击后继续在37℃细胞培养箱孵育。姜黄素预处理组使用不同浓度姜黄素预处理细胞后进行热打击。使用CCK-8法检测细胞增殖,流式细胞术检测细胞周期及细胞凋亡,分光光度法检测Caspase活性,ELISA法检测细胞因子。结果:热打击显著抑制HUVECs的活力(P<0.05),而姜黄素预处理能以剂量依赖的方式减轻热打击对HUVECs活力的抑制作用(P<0.05)。与正常对照组相比,热打击后HUVECs出现显著的G0/G1期阻滞(P<0.05),而姜黄素预处理能显著减少热打击诱导的G0/G1期阻滞(P<0.05)。热打击后HUVECs中凋亡细胞的比例明显升高(P<0.05),姜黄素预处理能够显著减少细胞凋亡(P<0.05)。Caspase活性检测提示姜黄素可以抑制热打击诱导的Caspase活化(P<0.05)。姜黄素预处理后,热打击诱导的TNF-α、MCP-1产生明显减少(P<0.05)。结论:姜黄素能显著抑制热打击诱导的内皮细胞凋亡和炎性细胞因子产生,对热打击诱导的血管内皮细胞损伤具有保护作用。     

肝细胞生长因子预处理对过氧化氢诱导大鼠神经干细胞凋亡的保护作用

目的研究肝细胞生长因子(HGF)对神经干细胞(NSC)凋亡的保护作用及其作用机制,为HGF用于NSC移植提供实验基础。方法分离培养大鼠NSC。细胞分为正常对照、模型(H2O2100μmo.lL-1)、HGF+H2O2(HGF15,30及60μg.L-1预处理24h后,再加入H2O2100μmol.L-1处理4h),LY294002(PI3K/Akt通路抑制剂)+HGF+H2O2(先加入LY29400220μmol.L-1处理30min,再加入HGF60μg.L-1处理24h,最后再加入100μmo.lL-1H2O2培养4h)组。MTT法检测细胞存活率;TUNEL法检测细胞凋亡率;比色法检测半胱氨酸天冬氨酸蛋白酶(caspase)-3活性;Western印迹分析Bcl-2,Bax蛋白表达。结果MTT检测发现,随着HGF浓度的增加,NSC细胞的存活率也增加。与模型组〔(63.5±2.4)%〕比较,HGF15,30及60μg.L-1预处理组细胞存活率明显升高〔(79.1±7.5)%,(83.8±6.1)%和(86.6±8.2)%;n=3,P<0.05〕。TUNEL法检测发现,HGF预处理组凋亡细胞明显减少,模型组的凋亡率为(43.5±6.2)%,HGF预处理组则分别为(34.2±8.6)%,(21.7±3.8)%及(19.4±4.0)%。Caspase-3活性检测表明,与模型组相比,HGF预处理组细胞caspase-3活性降低。Western印迹分析结果显示,与模型组比较,HGF预处理使细胞的Bcl-2蛋白表达升高,但Bax蛋白表达不受影响;HGF的抗凋亡效应可被PI3K/Akt通道阻滞剂LY294002阻断。结论HGF可减轻H2O2所诱导的大鼠NSC凋亡,且呈一定的浓度依赖关系,其作用机制可能与NSC的PI3K/Akt通路激活和Bcl-2表达增强有关。     

新生大鼠海马脑片培养方法

目的　建立新生大鼠海马脑片体外长期培养方法。方法　取出生后 10d的新生大鼠海马 ,切成30 0 μm厚的脑片 ,转至带有微孔膜插件的培养皿中进行培养。培养期间进行形态学观察 ,并通过MTT法鉴定组织活力 ,免疫组化法观察胶质细胞对损伤的反应 ,电生理反应以检测神经细胞功能。结果培养海马脑片逐渐变薄 ,5d后结构清晰 ,细胞形态完整 ;MTT法显示培养 4 0d内的海马组织均能保持高摄入MTT能力 ;在Schaffer侧枝给予单脉冲刺激 ,于CA1区能接收到完整的群峰电位 ;谷氨酸导致胶质细胞抗胶质纤维酸性蛋白高表达。结论　本方法培养 4 0d的海马脑片具有正常的活力和功能。     

Morphologic injury and lipid peroxidation in monolayer cultures of rabbit tracheal epithelium exposed in vitro to ozone

Numerous reports have documented airway epithelial damage and lipid peroxidation in the lungs of animals exposed to ozone. However, the response of isolated tracheal epithelial (TE) cells to ozone has not been extensively studied. To assess ozone-induced injury in cultured TE cells, an in vitro exposure system was developed in which cells were maintained at gas-fluid interface analogous to in vivo conditions. Confluent monolayer cultures of rabbit TE cells were exposed for 30 min to atmospheres of 5% CO2/air containing 0.05, 0.1, 0.5, 1, 2, 4, 6, or 8 ppm ozone. Morphologic injury was assessed by phase-contrast microscopy and by determination of TE cell number and viability (trypan blue dye exclusion) pre- and postexposure, and the lipid peroxide content of TE cells was measured as thiobarbituric acid (TBA) reactive substances. Exposure to 5% CO2/air alone did not affect monolayer morphology, cell number of viability. Cultures exposed to 0.05 or 0.1 ppm ozone demonstrated no consistent light microscopic changes, whereas exposure to 0.5 ppm and higher ozone concentrations caused distortion of monolayer morphology, cytoplasmic vacuolization, and decreased viability. Exposure to 0.5 or 1 ppm resulted primarily in cytoplasmic vacuolization while exposure to 2, 4, 6, or 8 ppm induced more pronounced cellular injury associated with cell necrosis (viability post 8 ppm ozone 75.0 +/- 7.0%, vs. 95.9 +/- 2.6% for 5% CO2/air controls). Ozone exposure also caused changes in cell shape, which on occasion resulted in loss of cell-to-cell contact. Increased production of TBA-reactive substances was detected in TE cells following ozone exposure, including exposure to 0.05 and 0.1 ppm. The morphologic changes induced by in vitro ozone exposure in the cultured TE cells were similar to those described in the tracheal epithelium of ozone-exposed animals and occurred independent of recruited inflammatory cells or extravasated circulating mediators.     

Hepatocyte growth factor attenuates pancreatic damage in caerulein-induced pancreatitis in rats.

Hepatocyte growth factor (HGF) overexpression was reported in experimental and clinical acute pancreatitis. These observations prompted us to determine the effect of HGF administration on the development of caerulein-induced pancreatitis in rats. Acute pancreatitis was induced by s.c. infusion of caerulein (10 microg/kg/h) for 5 h. HGF was administrated twice (30 min before caerulein or saline infusion and 3 h later) at the doses: 0.4, 2, 10 or 50 microg/kg s.c. Immediately after cessation of caerulein or saline infusion, the pancreatic blood flow, plasma amylase and lipase activity, plasma cytokines concentration, cell proliferation, and morphological signs of pancreatitis were examined. Caerulein administration induced acute edematous pancreatitis manifested by 41% decrease in DNA synthesis, 53% inhibition of pancreatic blood flow, a significant increase in plasma amylase and lipase activity, plasma interleukin-1beta and interleukin-6 concentration, as well as, the development of the histological signs of pancreatic damage (edema, leukocyte infiltration, and vacuolization). Administration of HGF without induction of pancreatitis increased plasma interleukin-10. Treatment with HGF, during induction of pancreatitis, increased plasma interleukin-10 and attenuated the pancreatic damage, what was manifested by histological improvement of pancreatic integrity, the partial reversion of the drop in DNA synthesis and pancreatic blood flow, and the reduction in pancreatitis evoked increase in plasma amylase, lipase, and interleukin-1beta and interleukin-6 levels. HGF administrated at the dose 2 microg/kg exhibited a similar beneficial effect as administration of HGF at the doses 10 or 50 microg/kg. Treatment with HGF at the dose 0.4 microg/kg was less effective. We conclude that: (1) administration of HGF attenuates pancreatic damage in caerulein-induced pancreatitis; (2) this effect seems to be related to the increase in production of interleukin-10, the reduction in release of interleukin-1beta and interleukin-6, and the improvement of pancreatic blood flow.     

Stable ciliary activity in human nasal epithelial cells grown in a perfusion system

PURPOSE: Explore the usefulness of a perfusion system in order to establish human nasal epithelial cell cultures suitable for long-term in vitro ciliary beat frequency (CBF) and cilio-toxicity studies. METHODS: The cells were obtained by protease digestion of nasal biopsy material. The cells were plated at a density of 0.8-1 x 10(6)/cm2 on Vitrogen-coated polyethylene terephthalate membranes, and cultured under submerged conditions in a CO2 incubator or in a perfusion system (initiated on days 8-9 after plating). The CBF was determined at 24.1 +/- 0.8 degrees C by a computerized microscope photometry system. The morphology of the cultured cells was characterized by transmission electron microscopy (TEM). RESULTS: Under CO2 incubator culture conditions, stable ciliary activity was expressed and maintained from day 2 to day 24. Under perfusion system culture conditions, the CBF (mean+/-S.D., n = 4) amounted to 8.4 +/- 0.9 and 8.8 +/- 0.4 Hz on days 7 and 14, respectively. These values were lower as compared to the corresponding CBF obtained in the CO2 incubator cultures (9.5 +/- 0.6 and 9.9 +/- 1.0 Hz, respectively). Reference cilio-stimulatory (glycocholate) and cilio-inhibitory (chlorocresol) compounds were used to assess CBF reactivity. In the CO2 incubator and 7- and 14-days perfusion system cultures, glycocholate (0.5%) showed a reversible cilio-stimulatory effect of 23, 26 and 21%, respectively, while chlorocresol (0.005%) exerted a reversible cilio-inhibitory effect of 36, 40 and 36%, respectively. TEM revealed polarized cuboidal to columnar epithelial morphology, with well-differentiated ciliated cells under CO2 and perfusion system conditions (up to day 23). CONCLUSION: Culturing human nasal epithelial cells on Vitrogen-coated polyethylene terephthalate membranes in submerged conditions in a CO2 incubator and in a perfusion system offers the possibility for long-term preservation (up to 22-24 days) of stable and reactive CBF in vitro.     

In vitro bioassay for transforming growth factor-beta using XTT method

Research in the cytokine field has grown exponentially in recent years, and the validity of such studies relies heavily on the appropriate measurement of levels of cytokines in various biological samples. Transforming growth factor (TGF)-beta, a hormonally active polypeptide found in normal and transformed tissue, is a potent regulator of cell growth and differentiation. The most widely used bioassay for TGF-beta is the inhibition of the proliferation of mink lung epithelial cells. Though detection of [3H]thymidine incorporation is more sensitive than the MTT assay, it presents some disadvantages due to the safety and disposal problems associated with radioisotopes. In this study, we attempted to ascertain the experimental conditions which could be used for measuring the in vitro biological activity of TGF-beta in a safer and more sensitive way compared with the currently available methods. We compared the commonly used method, the MTT assay, to the XTT assay using different parameters including cell number, incubation time and the wave length used for detecting the product. We examined the anti-proliferative activities of TGF-beta in three different cell lines: Mv-1-Lu mink lung epithelial cells, MCF10A human breast epithelial cells and H-ras-transformed MCF10A cells. Herein, we present an experimental protocol which provides the most sensitive method of quantifying the biological activity of TGF-beta, with a detection limit of as low as 10 pg/ml: Mv-1-Lu or H-ras MCF10 A cells (1 x 10(5)/well) were incubated with TGF-beta at 37 degrees C in a humidified CO2 incubator for 24 hr followed by XTT treatment and determination of absorbance at 450 or 490 nm. Our results may contribute to the establishment of an in vitro bioassay system, which could be used for the satisfactory quantitation of TGF-beta.