甲壳低聚糖对非肥胖性糖尿病小鼠胰岛细胞生长及胰岛素分泌量的影响

目的探讨甲壳低聚糖对非肥胖性糖尿病 (NOD)小鼠胰岛 β 细胞生长增殖和释放胰岛素的影响。方法通过胰导管逆行灌注胶原酶静止消化NOD小鼠胰腺及不连续密度梯度Ficoll液纯化胰岛细胞 ,并用转板以及碘乙酸处理的方法除去其中的成纤维细胞 ,得到比较纯的胰岛细胞。以此为材料 ,将细胞分为干预组及对照组 ,干预组在细胞培养液中加入 3%甲壳低聚糖 ,对照组在细胞培养液中加入生理盐水。分别检测细胞增殖情况和急性胰岛细胞释放胰岛素实验。结果干预组细胞增殖优于对照组 (P <0 .0 5 ) ,而急性胰岛素释放则两组相比较差异无显著性。结论甲壳低聚糖能够促进胰岛 β

降糖孜亚比提片(HZT)对大鼠乳鼠胰岛细胞生长及胰岛素分泌的影响

2型糖尿病及其并发症严重影响人类身体健康，在这一群体呈现逐年递增的情况下仍缺乏有效防治手段，关键在于对其发病机制认识不足。现在认为，2型糖尿病是一种高度异质性的多基因疾病，胰岛素抵抗和胰岛功能障碍是其发病机制中的两个主要环节，很少有2型糖尿病患者只存在胰岛素抵抗或胰岛功能不足。本文目的是通过从中药有效成分中寻找新型降糖药并以动物胰岛细胞作为研究对象。新疆维药降糖孜亚比提片（HZT）由马齿苋子、天竺黄、石榴花、欧玉竹等13种中药组成，具有调节胆液汁，生津止渴的作用。

游离脂肪酸促进基础状态胰岛细胞生长和分泌胰岛素

游离脂肪酸促进基础状态胰岛细胞生长和分泌胰岛素邵建华袁振芳李长红王淑凤高妍为探明游离脂肪酸对胰岛素分泌的影响及其作用机制，本实验利用体外培养大鼠胰岛细胞方法，研究了基础状态油酸和软脂酸对胰岛细胞生长和分泌功能的影响。一、材料和方法１．材料：Ｗｉｓｔａ...

胰岛素样细胞生长因子-1、碱性成纤维细胞生长因子及转化生长因子α对人表皮干细胞增殖的影响

目的表皮干细胞是组织工程化皮肤的"种子细胞"。文中研究碱性成纤维细胞生长因子(basic fibroblast growthfactor,bFGF)、胰岛素样细胞生长因子-1(insulin-like growth factor-1,IGF-1)和转化生长因子α(transforming growth factorα,TGFα)对人表皮干细胞增殖的影响。方法采用两步酶消化法和Ⅳ型胶原差速贴壁相结合的方法获得人原代表皮干细胞,将表皮干细胞分为A组(K-SFM)、B组(K-SFM+bFGF)、C组(K-SFM+IGF-1)及D组(K-SFM+TGFα)进行培养。比较不同组之间表皮干细胞的克隆形成率、生长增殖、生长曲线和细胞周期等指标。结果 B组、C组及D组培养的表皮干细胞在细胞增殖、细胞克隆率方面检测结果均明显高于A组(P<0.05);流式细胞仪检测B组、C组与A组及D组处于G0/G1细胞比例比较差异有统计学意义(P<0.05)。结论 IGF-1、bFGF及TGF-α均对表皮干细胞的增殖有促进作用,IGF-1及bFGF对表皮干细胞表型的维持有较好的作用。

TGF-β_1和IGF-1对人骨髓基质干细胞体外增殖和分化的影响

目的探讨转化生长因子β1(TGF-β1)和胰岛样细胞生长因子-1(IGF-1)对人骨髓基质干细胞(BMSC)体外增殖、分化的影响。方法8份标本分两组,每组4份,抽取骨髓,分离基质干细胞,体外连续传代培养,A组为基础培养液,B组加入TGF-β1和IGF-1,观察细胞生长情况及形态特征,阿新蓝染色,Ⅱ型胶原mRNA表达情况。结果B组细胞增殖速度及形态变化均较A组加快。阿新蓝染色:原代细胞阴性;传代细胞,A组淡染或阴性,B组呈蓝色;Ⅱ型胶原mRNA表达:A组未检出,B组阳性。结论TGF-β1和IGF-1在体外可诱导人BMSC分化为软骨样细胞,但同时其增殖能力减弱。

VEGF和IGF-1在代谢性酸中毒诱导的新生大鼠视网膜细胞中的表达

目的了解代谢性酸中毒诱导新生大鼠视网膜病变的发展进程,探讨其发生与血管内皮生长因子(VEGF)和胰岛素样细胞生长因子-1(IGF-1)的关系。方法模型组新生Sprague-Daw ley大鼠80只,从出生后第2天开始按535 mg.kg-1的剂量管饲NH4C l(质量浓度为50 mg.m l-1),每天2次,连续7 d,然后进入恢复期;另选未行管饲的80只新生大鼠作为对照组。两组大鼠分别于出生后第3、5、8、10、13、20天处死。取出双眼进行视网膜铺片和二磷酸腺苷酶染色,对视网膜血管进行评估;视网膜切片经常规HE染色定量反映视网膜血管增生情况;用免疫组化方法进行VEGF和IGF-1测定。结果模型组大鼠在出生后第3、5、8、10、13、20天新生血管(NV)发生率分别为0、7%、24%、59%、23%、0。HE染色可见实验组10 d龄鼠有较多突破视网膜内界膜的血管内皮细胞核,平均每张切片有(14.67±2.16)个。而对照组未见或极少见突破内界膜的血管内皮细胞核,每张仅(0.87±0.75)个,两者比较差异有统计学意义(t=18.47,P<0.000 1)。出生后第10、13天,模型组鼠VEGF的蛋白水平比对照组明显升高,差异有统计学意义(P<0.05)。出生后第8天,模型组大鼠视网膜IGF-1的蛋白水平比对照组明显下降,差异有统计学意义(P<0.05)。结论代谢性酸中毒可能损害了正在发育的视网膜血管而引起新生血管;视网膜新生血管的发生与VEGF和IGF-1的异常表达有关。

骨质疏松骨折愈合过程中IGF-I mRNA的基因表达

目的 探讨骨质疏松性骨折愈合过程中IGF ImRNA基因表达的细胞定位及基因表达模式。方法 利用去势SD大鼠造成Ⅰ型骨质疏松及其骨折模型 ,通过原位杂交及斑点杂交的方法 ,检测正常及骨质疏松性骨折骨痂局部IGF ImRNA的基因表达。结果 骨质疏松骨折与正常骨折愈合过程中IGF ImRNA基因表达的细胞定位无差别 ;骨质疏松骨折愈合过程中IGF ImRNA表达在骨折后第 9天 ,且较正常组高。结论 IGF I在骨质疏松骨折愈合中起重要的调节作用。

Reactivation of the insulin-like growth factor-Ⅱsignaling pathway in human hepatocellular carcinoma

Constitutive activation of the insulin-like growth factor (IGF)-signaling axis is frequently observed in human hepatocellular carcinoma(HCC).Especially the over- expression of the fetal growth factor IGF-Ⅱ,IGF-Ⅰ receptor(IGF-IR),and cytoplasmic downstream effectors such as insulin-receptor substrates(IRS)contribute to proliferation,anti-apoptosis,and invasive behavior. This review focuses on the relevant alterations in this signaling pathway and independent in vivo models that support the central role IGF-Ⅱsignaling during HCC development and progression.Since this pathway has become the center of interest as a target for potential anti-cancer therapy in many types of malignancies,various experimental strategies have been developed,including neutralizing antibodies and selective receptor kinase inhibitors,with respect to the specific and efficient reduction of oncogenic IGF-Ⅱ/IGF-IR-signaling.

Expression and significance of tumor-related genes in HCC

AIM: To investigate the expression and clinical significance of DEK, cyclin D1, insulin-like growth factor Ⅱ (IGF-Ⅱ), glypican 3 (GPC3), ribosomal phosphoprotein 0 (rpPO) mRNA in hepatocellular carcinoma (HCC) and its paraneoplastic tissues. METHODS: The expression of mRNAs of DEK, cyclin D1, IGF-Ⅱ, GPC3 and rpP0 mRNA was detected in HCC and its paraneoplastic tissues by multiplex RT-PCR. RESULTS: By the simplex RT-PCR, the overexpression of mRNAs of DEK, cyclin D1, IGF-Ⅱ, GPC3, rpP0 mRNA in HCC and its paraneoplastic tissues was 78.1%, 87.5%, 87.5%, 75.0%, 81.3% and 15.6%, 40.6%, 37.5%, 21.9%, 31.3% respectively (P<0.05). By the multiplex RT-PCR, at least one of the mRNAs was detected in all HCC samples and in 75.0% of paraneoplastic samples (P>0.05). However, all these five mRNAs were found in 68.8% of HCC samples, but only in 9.4% of paraneoplastic tissues (P<0.05). The positive expression of mRNAs of DEK, cyclin D1, IGF-Ⅱ, GPC3, rpP0 in well- and poorly-differentiated HCC was 89.0%, 66.7%, 66.7%, 66.7%, 77.8% and 73.9%, 95.7%, 95.7%, 95.7%, 82.6%, respectively (P>0.05). The expression of these genes in HCCs with α-feto protein (AFP) negative and positive was 90.0%, 80.0%, 90.0%, 90.0%, 90.0% and 72.7%, 86.3%, 77.3%, 90.9%, 68.2% respectively (P>0.05). CONCLUSION: The expression of DEK, cyclin D1, IGF-Ⅱ, GPC3, rpP0 mRNA in HCC is much higher in HCC than in its paraneoplastic tissues. Multiplex RT-PCR assay is an effective, sensitive, accurate, and cost-effective diagnostic method of HCC.

Effects of Basic Fibroblast Growth Factor and Insulin-like Growth Factor on Cultured Cartilage Cells from Skate Raja porasa

Effects of basic fibroblast growth factor (bFGF) and insulin like growth factor II (IGF II) on cartilage cells from proboscis of skate, Raja porasa Günther, were investigated in this study. The cartilage cells were cultured in 20% FBS supplemented MEM medium at 24℃. Twelve hours after culture initiation, the cartilage cells were treated with bFGF and IGF II at different concentration combinations. It was found that 20 ng/ml of bFGF or 80 ng/ml of IGF II was enough to have obvious stimulating effect on the growth and division of skate cartilage cells. Test of bFGF and IGF II together, revealed that 20 ng/ml of bFGF and 80 ng/ml of IGF II together had the best stimulating effect on the growth and division of skate cartilage cells. The cartilage cells cultured could form a monolayer at day 7.

Feeder-free maintenance of hESCs in mesenchymal stem cell-conditioned media： distinct requirements for TGF-β and IGF-Ⅱ

A paracrine regulation was recently proposed in human embryonic stem cells （hESCs） grown in mouse embryonic fibroblast （MEF）-conditioned media （MEF-CM）, where hESCs spontaneously differentiate into autologous fibroblastlike cells to maintain culture homeostasis by producing TGF-β and insulin-like growth factor-lI （IGF-Ⅱ） in response to basic fibroblast growth factor （bFGF）. Although the importance of TGF-β family members in the maintenance of pluripotency of hESCs is widely established, very little is known about the role of IGF-Ⅱ. In order to ease hESC cul- ture conditions and to reduce xenogenic components, we sought （i） to determine whether hESCs can be maintained stable and pluripotent using CM from human foreskin fibroblasts （HFFs） and human mesenchymal stem cells （hM- SCs） rather than MEF-CM, and （ii） to analyze whether the cooperation of bFGF with TGF-β and IGF-Ⅱ to maintain hESCs in MEF-CM may be extrapolated to hESCs maintained in allogeneic mesenchymal stem cell （MSC）-CM and HFF-CM. We found that MSCs and HFFs express all FGF receptors （FGFR1-4） and specifically produce TGF-β in response to bFGF. However, HFFs but not MSCs secrete IGF-Ⅱ. Despite the absence of IGF-Ⅱ in MSC-CM, hESC pluripotency and culture homeostasis were successfully maintained in MSC-CM for over 37 passages. Human ESCs derived on MSCs and hESCs maintained in MSC-CM retained hESC morphology, euploidy, expression of surface markers and transcription factors linked to pluripotency and displayed in vitro and in vivo multilineage developmental potential, suggesting that IGF-Ⅱ may be dispensable for hESC pluripotency. In fact, IGF-Ⅱ blocking had no effect on the homeostasis of hESC cultures maintained either on HFF-CM or on MSC-CM. These data indicate that hESCs are successfully maintained feeder-free with IGF-Ⅱ-lacking MSC-CM, and that the previously proposed paracrine mechanism by which bFGF cooperates with TGF-β and IGF-Ⅱ in the maintenance of hESCs in MEF-CM may not be fully extrapolated to hESCs maintained in CM from human MSCs.

Apoptosis in Granulosa cells during follicular atresia:relationship with steroids and insulin-like growth factors

It is well known that during mammalian ovarian follicular development, the majority of follicles undergo atresia at various stages of their development. However, the mechanisms controlling this selection process remain unknown. In this study, we investigated apoptosis in granulosa cells during goat follicular atresia by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The changes in the levels of steroids, insulin-like growth factors (IGFs) and IGF receptors were studied by radioimmunoassay (RIA) and semi-quantitative reverse transcrip-tion-PCR. We found that the percentage of apoptotic granulosa cells in the atretic (A) follicles was significantly higher than that in the slightly atretic (SA) and healthy (H) follicles. The level of estradiol and the ratio of estradiol to progesterone in H follicles were significantly higher than those in A follicles. On the other hand, the level of progesterone was not significantly different among these follicle types. We also found that the level of IGF-Ⅰ in H follicles was higher than in SA and A follicles, whereas the amount of IGF-Ⅱ did not vary significantly. The expression of IGF receptor also decreased in A follicles as compared to that in H and SA follicles. These results suggested that estradiol and IGF-Ⅰ might be involved in controlling apoptosis in granulosa cells during follicular atresia.

Effect of growth hormone on small intestinal homeostasis relation to cellular mediators IGF-I and IGFBP-3

AIM:To evaluate the effects of growth hormone(GH) on the histology of small intestines which might be related to the role of insulin like growth factor(IGF)-I, IGF-binding protein 3(IGFBP-3)and its receptors. METHODS:Twelve week-old adult male Wistar albino rats were divided into two groups.The study group(n =10),received recombinant human growth hormone (rGH)at a dose of 2 mg/kg per day subcutaneously for 14 d and the control group(n=10)received physiologic serum.Paraffin sections of jejunum were stained with periodic acid shift(PAS)and hematoxylin and eosin(HE) for light microscopy.They were also examined for IGF-I, IGFBP-3 and IGF-receptor immunoreactivities.Staining intensity was graded semi-quantitatively using the HS- CORE. RESULTS:Goblet cells and the cells in crypt epitheliawere significantly increased in the study group compared to that of the control group.We have demonstrated an increase of IGF-I and IGFBP-3 immunoreactivities in surface epithelium of the small intestine by GH application.IGF-I receptor immunoreactivities of crypt,villous columnar cells,enteroendocrine cells and muscularis mucosae were also more strongly positive in the study group compared to those of in the control group. CONCLUSION:These findings confirm the important trophic and protective role of GH in the homeostasis of the small intestine.The trophic effect is mediated by an increase in IGF-I synthesis in the small intestine, but the protective effect is not related to IGF-I.

C-peptide and Diabetic Encephalopathy

With the changes of life style, diabetes and its complications have become a major cause of morbidity and mortality. It is reasonable to anticipate a continued rise in the incidence of diabetes and its complications along with the aging of the population, increase in adult obesity rate, and other risk factors. Diabetic en- cephalopathy is one of the severe microvascular complications of diabetes, characterized by impaired cogni- tive functions, and electrophysiological, neurochemical, and structural abnormalities. It may involve direct neuronal damage caused by intracellular glucose. However, the pathogenesis of this disease is complex and its diagnosis is not very clear. Previous researches have suggested that chronic metabolic alterations, vascular changes, and neuronal apoptosis may play important roles in neuronai loss and damaged cognitive functions. Multiple factors are responsible for neuronal apoptosis, such as disturbed insulin growth factor （IGF） system, hyperglycemia, and the aging process. Recent data suggest that insulin/C-peptide deficiency may exert a primary and key effect in diabetic encephalopathy. Administration of C-peptide partially improves the condition of the IGF system in the brain and prevents neuronal apoptosis in the hippocampus of diabetic patients. Those findings provide a basis for application of C-peptide as a potentially effective therapy for diabetes and diabetic encephalopathy.

新疆90例贲门癌中IGF-IR、bcl-2、PCNA的表达及其意义

目的:探讨胰岛素样生长因子-Ⅰ受体(IGF-IR)、细胞凋亡相关基因-2(bcl-2)及增殖细胞核抗原(PCNA) 的异常表达在新疆3个不同民族贲门癌发生发展中的作用及其病理生物学意义,为此病的防治提供实验资料。方法:应用免疫组化LSAB法检测90例贲门腺癌和21例非癌组织的IGF-IR、bcl-2、PCNA蛋白的阳性表达情况。结呆:(1)IGF-IR、bcl-2蛋白、PCNA在90例贲门腺癌中的检出率分别为84．44％(69/90)、87．78％(79/90)、97．78％ (88/90),在贲门非癌良性组织中的阳性检出率分别为47．62％(10/21)、52．38％(11/21)、0％(0/21)。IGF-IR、bcl- 2、PCNA的阳性率在癌和非癌组织间均具有统计学的差异(P<0．01)。(2)哈萨克族(哈族)、维吾尔族(维族)、汉族各民族之间IGF-IR、bcl-2、PCNA阳性率的差异均无统计学意义(P>0．05)。(3)IGF-IR、bcl-2、PCNA在贲门腺癌不同分化程度中阳性率的差异均无统计学意义(P>0．05)。(4)贲门腺癌中bcl-2,与IGF-IR间、bcl-2与PC- NA间无相关关系(P>0．05)。结论:(1)IGF-IR蛋白、癌基因bcl-2和PCNA的异常表达在贲门癌变过程中具有重要作用。(2)贲门癌组织中IGF-IR、bcl-2、PCNA表达在肿瘤不同分化程度和不同民族间无显著差别。

Insulin promotes sinusoidal endothelial cell proliferation mediated by upregulation of vascular endothelial growth factor in regenerating rat liver after partial hepatectomy

AIM： To determine whether insulin could promote sinusoidal endothelial cell （SEC） proliferation mediated by upregulation of vascular endothelial growth factor （VEGF） in regenerating rat liver after partial hepatectomy （PHx）. METHODS： Adult male Sprague-Dawley rats undergoing 70% PHx were injected with insulin （300 MU/kg） or saline via the tail veins every 8 h after surgery for 7 d and killed at 0, 24, 48, 72, 96, 120, 144, and 168 h after surgery. Proliferation of both hepatocytes and SECs was monitored by evaluating the proliferating cell nuclear antigen （PCNA） labeling index （LI）. The expression of VEGF protein was evaluated by immunohistochemistJv. The mRNA expressions of VEGF and its receptors FIt-1 and FIk-1 were evaluated by semi-quantitative reverse transcription-PCR. RESULTS： Insulin markedly increased the expression of VEGF mRNA between 24 and 120 h after hepatectomy compared to controls. Similarly, insulin significantly increased the expression of Fit-1 between 24 and 96 h. However, insulin had no significant effect on FIk-1. Furthermore, the immunohistochemical staining revealed that expression of VEGF protein increased in the insulin groups. Insulin significantly increased the PCNA LI of hepatocytes and SECs compared to controls. CONCLUSION： Exogenous insulin may promote SEC proliferation with an enhanced expression of VEGF and its receptor Fit-1 in regenerating rat liver after PHx.

Insulin-like growth factor binding protein-5 influences pancreatic cancer cell growth

AIM： To investigate the functional significance of insulin-like growth factor binding protein-5 （IGFBP-5） overexpression in pancreatic cancer （PaC）.METHODS： The effects of IGFBP-5 on cell growth were assessed by stable transfection of BxPC-3 and PANC-1 cell lines and measuring cell number and DNA synthesis. Alterations in the cell cycle were assessed by flow cytometry and immunoblot analyses. Changes in cell survival and signal transduction were evaluated after mitogen and phosphatidylinositol activated protein kinase 3-kinase （PI3K） inhibitor treatment.RESULTS： After serum deprivation, IGFBP-5 expression increased both cell number and DNA synthesis in BxPC-3 cells, but reduced cell number in PANC-1 cells. Consistent with this observation, cell cycle analysis of IGFBP-5-expressing cells revealed accelerated cell cycle progression in BxPC-3 and G2/M arrest of PANC-1 cells. Signal transduction analysis revealed that Akt activation was increased in BxPC-3, but reduced in PANC-1 cells that express IGFBP-5. Inhibition of PI3K with LY294002 suppressed extracellular signal-regulated kinase-1 and -2 （ERK1/2） activation in BxPC-3, but enhanced ERK1/2 activation in PANC-1 cells that express IGFBP-5. When MEK1/2 was blocked, Akt activation remained elevated in IGFBP-5 expressing PaC cells; however, inhibition of PI3K or MEK1/2 abrogated IGFBP-5-mediated cell survival.CONCLUSION： These results indicate that IGFBP-5 expression affects the cell cycle and survival signal pathways and thus it may be an important mediator of PaC cell growth.

Effects of IGF-1 and oxLDL on expression of phosphatase PHLPP1 in vascular smooth muscular cells

Objective To investigate the effects of insulin-like growth factor-1 （IGF-1） and oxidized low density lipoprotein （oxLDL） on expression ofphosphatase PHLPP 1 in vascular smooth muscle cells （VSMCs）. Methods Rabbit aortic VSMCs were cultured. VSMCs proliferation ability was determined by measuring cell number and mitochondrial dehydrogenase （MD） activity with MTT assay. Western blot was used to detect the protein expression ofphosphatase PHLPP1. Results IGF-1 （100ug/L） increased cell number and MD activity to 3.02 and 3.59 times of that in control group, oxLDL（501xg/ml） elevated the above two parameters to 2.03 and 2.91 times respectively. Western blot showed that IGF-1 and oxLDL inhibited the expression of PHLPPI to 39.27% and 40.26% of the control group （P〈0.01 ）. Conclusion IGF- 1 and oxLDL may enhance the proliferation of VSMCs by decreasing the expression ofphosphatase PHLPP 1.

Effects of ethanol on insulin-like growth factor-Ⅰ system in primary cultured rat hepatocytes: Implications of JNK1/2 and alcoholdehydrogenase

AIM: To evaluate the effects of ethanol on the insulin- like growth factor-Ⅰ (IGF-Ⅰ) system involved in c-Jun N-terminal kinase (JNK1/2) and alcoholdehydrogenase (ADH) activity in primary cultured rat hepatocytes. METHODS: Hepatocytes isolated from male Sprague-Dawley rats were incubated with various concentrations of ethanol for different durations of time. The cells were pretreated with SP600125 (10 μmol/L) and 4-MP (200 μmol/L), and then treated with ethanol (200 mmol/L). We then measured IGF-Ⅰ secretion, IGF-Ⅰ mRNA expression, cell viability and JNK1/2 activity by radioimmunoassay, RT-PCR, MTT assay and Western blot, respectively (n = 6). RESULTS: Ethanol induced the activity of phospho (p)-JNK1/2, reaching a maximum at 60 min and then decreasing at 180 min. The effects of ethanol on the IGF-Ⅰ system were increased at 60 min (secretion: 7.11 ± 0.59 ng/mg protein vs 4.91 ± 0.51 ng/mg, mRNA expression: 150.2% ± 10.2% vs 101.5% ± 11.3%, P = 0.045) and then decreased at 180 min (secretion: 3.89 ± 0.25 ng/mg vs 5.4 ± 0.54 ng/mg protein; mRNA expression: 41.5% ± 10.4% vs 84.7% ± 12.1%, P = 0.04), however cell viability was decreased in a dose- and time-dependent manner. SP600125 blocked the ethanol-induced changes (at 60 min). Additionally, 4-methylpyrazole prevented the ethanol-induced decreases in the IGF-Ⅰ system, cell viability and p-JNK1/2 activity (at 180 min). CONCLUSION: This study suggests that ethanol- induced p-JNK1/2 activation is associated with the IGF-Ⅰ system and cell viability in hepatocytes. Furthermore, alcohol dehydrogenase is involved in the relationship between ethanol-induced inactivation of p-JNK1/2 and the changes of the IGF-Ⅰ system and cell viability.

IGF-1 mRNA expression of adult rat thyroid cell cultured in vitro

Objective: To investigate the law of age-related changes of insulin-like growth factor-1 (IGF-1) expression of rat thyroid cells cultured in vitro. Methods: Rat thyroid of different age (10, 45, 65, 100, 150 weeks) was isolated and thyrocytes cultured. Total RNA was extracted in different rat age group when thyroid cells had been cultured for two weeks. mRNA IGF-1 expression was measured with reverse-transcription polymerase chain reaction( RT-PCR) in each group and compared. Results: Quantity of total RNA in thyroid cells decreased with ageing when the rat thyroid cells had been cultured for 2 weeks. There is significant difference among groups (P<0.05). Expression of IGF-1 mRNA could be detected in thyroid cells of different age cultured in vitro. Quantity of IGF-1 mRNA expression by RT-PCR analysis increased from 10 to 45 weeks old, and then decreased with ageing. Conclusion: Rat thyroid cells from different age cultured in vitro can express IGF-1 mRNA. Quantity of total RNA in thyroid cells cultured in vitro decreased with aging. IGF-1 mRNA expression was correlated to age (r=0.401, P<0.05).