Establishment of a novel method for primary culture of normal human cervical keratinocytes

Background Cervical keratinocytes are recovered at a low numbers and frequently associated with contaminating human fibroblasts which rapidly overgrow the epithelial cells in culture with medium supplemented with 10% fetal bovine serum （FBS）. However, it is difficult to initiate keratinocyte cultures with serum-free keratinocyte growth medium alone because cell attachment can be poor. Therefore, the culture of these cells is extremely difficult. In this study, we described a modified culture medium and coated culture plastics for growing normal human cervical epithelial cells in vitro. Methods Normal cervical epithelial tissue pieces were obtained and digested with type I collagenase to dissociate the cells and a single cell suspension produced. The cells were cultured on plastic tissue culture substrate alone or substrate coated with collagen type I from rat tail, with modified keratinocyte serum-free medium （K-SFM） supplemented with 5% FBS. After attachment, the medium were replaced with K-SFM without FBS. The expression of basal keratins of the ectocervical epithelium, K5, K14 and K19 were assayed by immunofluorescence with monoclonal antibodies to identify the cell purity. Results Our results indicate that cells attached to the culture plastic more quickly in K-SFM supplemented with 5% FBS than in K-SFM alone, as well as to tissue culture plastic coated with collagen type I than plastic alone. The modified medium composed of K-SFM and 5% FBS combined with a specific tissue culture plastic coated with collagen type I from rat tail was the best method for culture of normal cervical epithelial cells. K5, K14 and K19 were assayed and keratinocyte purity was nearly 100%. Conclusion A novel, simple and effective method can be used to rapidly obtain highly purified keratinocytes from normal human cervical epithelium.     

Analysis of CK-19,PDX-1,Nestin,Ngn3 in different donor islet purity in rats

Objective: To investigate if there are the CK-19, PDX-1, Nestin, Ngn3 positive cells in the donor islets of different purity in rats. Methods: Thirty male adult SD rats were randomly divided into 3 groups. Islets were isolated using digestion by ductal injection of collagenase. Group Ⅰ (n=10): Separating cell preparations were not purified, Group Ⅱ(n=10): Islet sediment was purified with 25% Ficoll400 ,Group Ⅲ (n=10): Islet sediment was purified with 25% and 11% Ficoll-400. The levels of protein of CK-19, PDX-1, Nestin and Ngn3 were detected by immunohistochemistry and the mRNA of CK-19, PDX-1, Nestin, Ngn3 was amplified by RT-PCR. Results: After two different purification methods applied, three islet preparations of different purities were obtained. The difference of islet purity was significant among various groups (P＜0.05). Compared with group Ⅱ and group Ⅲ,the protein and mRNA of CK-19, PDX-1, Nestin,Ngn3 were both higher in group Ⅰ; group Ⅲ was poorly expressed. Conclusions: The three different islet purity donor islet have different CK-19, PDX-1, Nestin, Ngn3 positive cells within them, indicating that there are some islet stem cells in the purified donor islet.     

Culture and purification of human fetal olfactory ensheathing cells using different attachment rates combined with intermittent NT3 nutrition

Objective：To explore a simple and pragmatic method to obtain sufficient olfactory ensheathing cells from human fetus by selective attachment of harvested cells combined with intermittent NT3 nutrition. Methods：DMEM/F12 culture solution including 10% fetal bovine serum or NT3 was used to culture olfactory ensheathing cells intermittently every 48 h. The cell state and growth rates of OECs were observed, and P75 staining was used to estimate the purity of the cells. Results：Human fetal OECs were positive with P75 immunocytochemical staining. OECs in dipolar or tripolar shape formed networks by their processes in vitro. The purity of OECs in ＂good state＂ was about 95% at 9 d and 83% on 12 d, respectively. Conclusion：The method of using different attachment rates combined with intermittent NT3 addition is a simple and effective way to culture and purify OECs.     

Culture of rat retinal ganglion cells

This study aimed to modify the mixed and purified culture of rat retinal ganglion cells(RGCs) in vitro.The retinae of 1-3 day old Sprague-Dawley(SD) rats were separated bluntly into two layers:inner layer and outer layer,under a surgical microscope.Retinal cells isolated from different layers(inner layer,outer layer and whole retinal tissue) by using enzyme dissociation method were cultured in F12/DMEM medium containing 15% FBS.After 3-day culture,the RGCs in the retinal cells obtained from mixed culture of inner,outer,and whole retinal tissue were identified by immunocytochemical staining of Thy-1.1,and the rate of RGCs to retinal cells(RGCs%) was calculated.Two monoclonal antibodies,anti-macrophages/granulocytes(OX-41) against rat macrophage and antibody against rat Thy-1.1(OX-7),were used to purify RGCs by either a conventional or modified two-stepped immunopanning procedure(purification in situ).Purified RGCs were seeded at different cell density and cultured in F12/DMEM medium containing 15% FBS.Immunocytochemical staining for Thy-1.1,MTT,and PI-Hoechst33342 fluorescence imaging were used to identify the purity and the viability of RGCs in purified culture of RGCs.The results showed:(1) Immunocytochemistry of different retinal tissue layers culture revealed that the RGCs% was(19.9±1.2)%,(0.5±0.2)%,and(6.2±1.7)% respectively in the mixed culture of inner,outer,and whole retinal tissue,with differences being significant(P<0.05);(2) fluorescent double staining of Hoechst33342 and PI indicated that with the same RGCs%,RGCs obtained from purification in situ grew well with more neurite outgrowth than those by the conventional two-stepped immunopanning method;(3) the viability of purified RGCs seeded at high density was in-creased and the cells developed complex intercellular networks.The viability of RGCs was declined with the decreasing seeding density,and most cells presented round or oval in shape with thin neurites.It was concluded that:(1) RGCs% in the inner layer retina was higher than that in the outer layer retina;(2) RGCs obtained by in situ purification had more neurite outgrowth and lower mortality than those by conventional two-stepped immunopanning procedure;(3) the viability of purified RGCs could be increased by increasing cell seeding density to some extent.     

Both Juxtacrine and Paracrine Signaling Indispensable in Spermatogonial Stem Cell Cultures

Objective To prove that juxtacrine and paracrine signaling are essential in the culture of spermatogonial stem cells （SSCs） with Sertoli cell feeder layer in vitro. Methods Mice aged 7 d were chosen to harvest testes. A two-step enzyme digestion method was applied in testis suspension. The SSCs and Sertoli cells were separated by adherence distinguishing methods and biologically identified by immunofluorescence and Oil Red 0 staining methods. Flow cytometry was used to analyze purity of SSCs. Three groups were constructed according to different culture conditions. SSC and Sertoli cell co-culture group, SSC conditional culture group and SSC routine culture group. The conditional medium was collected from supernate of culture Sertoli cell in vitro and double-concentrated with DMEM/F12 and fetal bovine serum in a proportion of 4.5 ： 4.5 ： 1. The routine medium was DMEM/F12 containing 10% fetal bovine serum. Adherence rates were measured by Trypan blue staining. Absorbance of SSCs of each group was measured by MTT assay and proliferation curves shown to demonstrate proliferative features of SSCs. Proliferative features and colony formation were observed by inverted microscope. With 24 h difference in adherence rates, proliferations were compared and analyzed.Results The adherence rate of co-culture group was greater than that in the others（P〈0.05）, with insignificant difference in conditional culture group and routine group （P〉0. 05）. SSCs of co-culture group showed stable proliferation immediately following inoculation..4 stable colony formed within 7-10 d and maintained for 30 d. SSCs in conditional culture group and routine group decreased rapidly following transient proliferation. Conclusion The actions of SSCs in Sertoli cell cultures in vitro depended on both juxtacrine and paracrine signaling, Sertoli cell paraerine signaling was unable to promote SSC adherence and proliferation alone.     

Effect of antisense transfecting of monocarboxylate transporter gene on biological characteristics of lung adenocarcinoma A549 cells

Objective: To study the influence of transfecting antisense expression vector of the first subtype of the monocarboxylate transporter (MCT1) gene into lung cancer cells on pHi regulation, lactate transportation and cell growth. Methods: MCT1 antisense gene recombinant vector was introduced into human lung cancer cell line A549 by electroporation. The transfected A549 cells resistant to G418 were selected. Positive clones were examined by using PCR. The changes of intracellular pH and lactate were examined with spec-trophotometric method. Cell growth was studied with cell growth curve. Results: Intracellular pH and lactate were remarkably decreased in the cells transfected pLXSN-MCT1 in comparison with A549 cells without transfection (P<0. 001). The growth of A549 cells transfected pLXSN-MCTl was also inhibited remarkably. Conclusion: MCT1 gene may play an important role in pHi regulation, lactate transportation and cell growth in tumor cells.     

Transplantation of human limbal cells cultivated on amniotic membrane for reconstruction of rat corneal epithelium after alkaline burn

Background The transplantation of limbal epithelial cells cultivated on amniotic membrane is a newly developed treatment for limbal stem cell deficiency. The purpose of our study was to investigate the biological characteristics of limbal epithelial cells and evaluate the effect of transplantation of cultivated human limbal epithelial cells on ocular surface reconstruction in limbal stem cell deficiency rat model.Methods Human limbal cells were isolated and cultivated in vitro. Cytokertins 3, 12, and 19 (K3, K12 and K19) and p63 were detected by immunofluorescent staining or RT-PCR. BrdU labelling test was used to identify the slow cycling cells in the cultures. Limbal stem cell deficiency was established in rat cornea by alkali burn.Two weeks after injury, the rats received transplants of human limbal stem cells cultivated on amniotic membrane carrier. The therapeutic effect was evaluated by slit lamp observation, Hemotoxin and Eosin (HE) staining and immunofluorescent staining.Results On day 7 in primary culture, p63 and K19 were strongly expressed by most cells but only a few cells expressed K3. On days 14 and 21, p63 and K19 were still expressed by a majority of cells, but the expressive intensity of p63 decreased in a number of cells, while the proportion of K3 positive cells increased slightly and some cells coexpressed p63 and K3. RT-PCR showed that gene expression of both p63 and K12 were positive in cultivated limbal cells, but in mature superficial epithelial cells, only K12 was detected. BrdU labelling test showed that most cells were labelled with BrdU after 7 days‘ labelling and BrdU label retaining cells were observed after chasing for 21 days with BrdU free medium. For in vivo test, slit lamp observation, HE staining and immunofluorescent staining showed that the rats receiving transplant of human limbal stem cells cultivated on amniotic membrane grew reconstructed corneas with intact epithelium, improved transparency and slight or no neovascularization. A majority of epithelial cells of the reconstructed cornea were positive to antihuman nuclear antibody and cells expressing K3 were found mainly in superfacial epithelium.Conclusions Limbal stem cells can be cultivated in vitro: the cells are characterized by high proliferation and slow cycling and identified as p63/K19 positive and K3/K12 negative. During culture, some stem cells can proliferate and differentiate into mature cornea epithelial cells. Amniotic membrane is a suitable carrier for limbal stem cells. Transplantation of human limbal stem cells cultivated on amniotic membrane can functionally reconstruct rat cornea with limbal stem cell deficiency.     

Growth suppression of human lung cancer cells and implanted tumors by adenovirus-mediated transfer of the PTEN gene

This study examined the effects of a recombinant adenovirus AdTEN-EGFP on the proliferation of A549 cells, a human lung carcinoma cell line, in vitro and on the growth of the implanted tumors in the nude mice in vivo, explored the underlying mechanisms and evaluated the in vitro transfection efficiency of Ad-PTEN-EGFP into A549 cells. The expression of Ad-PTEN-EGFP in the A549 cells was determined. The proliferation and the apoptosis rates of the A549 cells with Ad-PTEN-EGFP transfection or not was detected by MTT and flow cytometry. Ad-PTEN-EGFP at different doses was injected intratumorally to the tumor-bearing mice induced by the A549 cells. Tumor sizes were measured on an alternate day. After all the mice were sacrificed, the implanted tumors were removed for routine histological examination, weight test, HE staining and immunohistochemical staining. The expressions of Bax, P16 and P53 in the tumor tissues and those of caspase-3, CD34 and VEGF in the mouse sera were detected. Tumor cell apoptosis was measured by TUNEL method. The results showed that the vitality of the A549 cells after transfection with Ad-PTEN-EGFP declined. The expression of green fluorescent protein was observed under fluorescent microscope. The transfection rate was in excess of 50%. The mRNA and protein expression of PTEN in the transfected cells was confirmed. The proliferation rate of the transfected cells was significantly decreased when compared with that of the non-transfected cells （P〈0.05）. The number of the apoptosi＇s cells was increased in the transfected cells （P〈0.05）. The models of implanted tumors were successfully estab- lished by injection of the A549 cells in the flank of Balb/c nude mice. Administration of Ad-PTEN-EGFP to the tumor-bearing nude mice resulted in a suppression of tumor growth. There were statistically significant differences in the tumor weight and tumor volume between the Ad-PTEN-EGFP-treated group and the control groups （P〈0.05）. In contrast to those in the control groups, tumor tissues in the Ad-PTEN-EGFP-treated group were shown to have typical extensive vacuolar degeneration and massive hemorrhagic necrosis. Apoptotic bodies were also observed in the tumor cells. The expressions of Bax, caspase-3 and P16 were increased （P〈0.05） while those of CD34, VEGF and P53 decreased （P〈0.05） in the Ad-PTEN-EGFP-treated group. It is concluded that Ad-PTEN-EGFP could induce the apoptosis of the A549 cells and inhibit their proliferation. And it could also substantially suppress the tumor growth in the tumor-bearing nude mice and induce apoptosis of the tumor cells as well. These findings carry significant implications for adenovirus vector-based PTEN gene therapies for lung cancers.     

Polymorphism of apolipoprotein A5 is a risk factor for cerebral infarction in type 2 diabetes

Summary To establish a better method of primary culture for alveolar epithelial type II cells (AEC II) and to study its bionomics, alveolar epithelial type II cells were isolated by digestion with trypsin and collagenase, which were then purified by plated into culture flask coated with rat immunoglobulin G. The purified AEC II were identified by alkaline phosphatase staining, electron microscopy, immunocytochemical staining of pulmonary surfactant protein A (SPA). The SPA expression and transfection characteristics were compared with those of A549 cell line. The results showed that AEC II could be isolated by digestion with trysin and collagenase and purified by adhesive purification by using IgG, with a yield of about 2–3 × 10⁷, and a purity of about 75%–84%. Cells could be quickly identified with AKP staining. AEC II were different from A549 cell line in terms of SPA expression and transfection characteristics. It is concluded that adhesive purification with IgG can improve the purity of AEC II, and AKP staining is simple in cell identification. AEC II can not be completely replaced by A549 cells in some studies because the differences between them, such as SPA expression. This project was supported by grants from the National Natural Sciences Foundation of China (No. 30500224 and No. 30400193).     

Primary Culture of Alveolar Epithelial Type Ⅱ Cells and Its Bionomic Study

To establish a better method of primary culture for alveolar epithelial type Ⅱ cells (AEC Ⅱ) and to study its bionomics, alveolar epithelial type Ⅱ cells were isolated by digestion with tryp- sin and collagenase, which were then purified by plated into culture flask coated with rat immu- noglobulin G. The purified AEC Ⅱ were identified by alkaline phosphatase staining, electron mi-croscopy, immunocytochemical staining of pulmonary surfactant protein A (SPA). The SPA expres-sion and transfection characteristics were compared with those of A549 cell line. The results showed that AEC Ⅱ could be isolated by digestion with trysin and collagenase and purified by adhesive pu- rification by using IgG, with a yield of about 2-3×107, and a purity of about 75%-84 %. Cells could be quickly identified with AKP staining. AEC Ⅱ were different from A549 cell line in terms of SPA expression and transfection characteristics. It is concluded that adhesive purification with IgG can improve the purity of AEC Ⅱ, and AKP staining is simple in cell identification. AEC Ⅱ can not be completely replaced by A549 cells in some studies because the differences between them, such as SPA expression.     

脂多糖下调过氧化物酶增殖体激活受体γ在大鼠原代肺泡Ⅱ型上皮细胞的表达

目的 观察脂多糖(lipopolysaccharide,LPS)作用下大鼠肺泡Ⅱ型上皮(type Ⅱ alveolar epithelial,AT-Ⅱ)细胞过氧化物酶增殖体激活受体γ(PPARγ)的表达变化情况.方法 通过酶消化分离和免疫黏附法纯化原代培养AT-Ⅱ细胞,并进行碱性磷酸酶、肺表面活性物质相关蛋白A(SP-A)和电镜鉴定.采用RT-PCR法检测细胞经LPS作用后PPARγ、TNF-α、SP-A mRNA的改变,Western blot法检测LPS作用后细胞PPARγ,表达,ELISA法检测TNF-α蛋白表达.结果 经碱性磷酸酶、SP-A和电镜鉴定,原代培养AT-Ⅱ细胞成功;在致炎因子LPS作用下,PPARγ,mRNA和蛋白表达均下降,这一变化伴随炎性因子TNF-α的升高.结论 在LPS作用下,AT-Ⅱ细胞内PPARγ表达降低,提示PPARγ参与炎症反应.     

肝细胞生长因子对高氧暴露早产鼠肺泡Ⅱ型上皮细胞增殖与凋亡的影响

目的:观察肝细胞生长因子(hepatocyte growth factor,HGF)对高氧暴露体外培养的早产鼠肺泡Ⅱ型上皮细胞(Type Ⅱ alveolar epithelial cells,AEC Ⅱ)增殖、凋亡及功能的影响,探讨HGF对高氧肺损伤保护作用的机制.方法:原代培养早产鼠AEC Ⅱ,纯化后随机分为4组:空气组(Air)、高氧组(HO)、空气 HGF组(Air HGF)、高氧 HGF组(HO HGF).采用流式细胞术及免疫印迹(Western blot)法观察AEC Ⅱ的增殖和凋亡情况,RT-PCR分析各组肺泡表面活性物质蛋白(surfactant associated protein,SP)SPA,SPB,SPC mRNA表达.结果:(1)各组细胞周期比例及细胞凋亡显示,与Air组比,HO组Sub G1(代表凋亡细胞比例),G0期/G1期细胞比例明显增高(P＜0.01),G2期/M期细胞比例明显降低(P＜0.01);Air HGF组S期细胞比例明显增高(P＜0.01).与HO组比,HO HGF组G0期/G1期细胞比例显著降低(P＜0.01),S期和G2期/M期细胞比例明显增高(P＜0.01).(2)各组增殖细胞核抗原表达显示,HO组显著低于Air组(P＜0.01),Air HGF组明显高于Air组(P＜0.05);HO HGF明显高于HO组(P＜0.05).(3)各组SPA,SPB,SPC mRNA表达显示,HO组强度较Air组弱(P＜0.01),而HO HGF组较HO组明显增加(P＜0.05).结论:高氧导致早产鼠AEC Ⅱ增殖抑制,凋亡增加,SPA,SPB,SPC mRNA表达降低,HGF可部分抑制这种变化,提示HGF对高氧肺损伤起一定的保护作用.     

原代人子宫内膜细胞分离及培养鉴定

目的：探究原代人子宫内膜细胞分离及培养的简易方法,并对其纯度及生物活性进行鉴定。方法采用胶原酶消化人子宫内膜组织,经2次筛网过滤、离心及贴壁纯化技术,分离、纯化培养人子宫内膜间质细胞（ESC ）和腺上皮细胞（EEC ）,用细胞角蛋白（cytokeratin）和波形蛋白（vimentin）免疫细胞化学染色法和免疫荧光方法对所分离的细胞进行鉴定。结果 ESC呈平行生长,细胞呈梭形或多角形,波形蛋白抗体免疫细胞化学染色呈阳性,纯度达95％以上。EEC呈漩涡状生长,细胞呈多角形或蝌蚪形,细胞角蛋白抗体免疫细胞化学染色呈阳性,纯度可达90％。结论应用胶原酶消化法及二次筛网过滤法成功分离并培养数量、活力和纯度高的子宫内膜细胞,可操作性强,可供具备基本细胞培养条件的实验室进行推广。     

酶消化法分离老龄SD大鼠血管平滑肌细胞

目的采用酶消化法培养老龄SD大鼠血管平滑肌细胞,为血管疾病的研究提供大量的原代平滑肌细胞。方法无菌取老龄SD大鼠主动脉,采用0.2%Ⅱ型胶原酶消化分离血管平滑肌细胞,自然纯化及差速贴壁纯化血管平滑肌细胞,免疫组化鉴定平滑肌细胞α肌动蛋白。结果免疫组化染色显示细胞纯度在95%以上。结论酶消化法用于血管平滑肌细胞的培养有利于获得大量的高纯度细胞供实验研究。     

人胚肺发育不同阶段表面活性物质相关蛋白-D的表达及意义

目的观察肺表面活性物质相关蛋白-D(SP-D)在人胚胎肺发育成熟过程中表达的特征.方法取11～36周人胎肺组织常规石蜡包埋切片,HE染色观察胚肺各个发育阶段的成熟度,免疫组化检测SP-D时相性表达特征.结果人胚胎发育12周肺组织开始表达SP-D,定位于胚肺支气管上皮和肺泡Ⅱ型细胞(AECⅡ)胞质内,在胚肺发育小管期和囊泡期逐渐表达增强;开始由支气管近端逐渐向肺泡Ⅱ型细胞迁移.肺发育末期至出生后,SP-D均在AECⅡ中稳定表达. 结论SP-D随着胎肺发育成熟,表达逐渐增强,阳性细胞开始出现于胚肺支气管上皮细胞,逐渐定位于肺泡Ⅱ型细胞.     

高纯度子宫内膜腺上皮细胞的体外分离和培养

目的:在体外建立子宫内膜腺上皮细胞原代分离和培养的方法,以获得高纯度子宫内膜腺上皮细胞。方法:选择正常子宫内膜组织,通过消化、过滤、选择性贴壁和二次消化等技术进行体外培养。结果:采用胶原酶二次消化法和选择性贴壁法成功实现子宫内膜腺上皮细胞的高纯度分离和原代培养。结论:采用胶原酶二次消化法和选择性贴壁法可高纯度分离子宫内膜腺上皮细胞及间质细胞。     

大鼠肺泡Ⅱ型上皮细胞的体外培养及内毒素攻击模型的建立

目的探讨大鼠肺泡Ⅱ型上皮细胞（ATⅡ）体外培养的方法及建立脂多糖（LPS）攻击ATⅡ的模型模拟内毒素性肺损伤。方法分离、纯化、鉴定得到大鼠ATⅡ,分别用01、1、10μg／ml的LPS刺激ATⅡ,并利用细胞增殖／毒性检测试剂在刺激2、4、6h后分别检测ATⅡ的抑制率,从而探索内毒素性肺损伤细胞模型中最适的LPS浓度和刺激时间。结果用碱性磷酸酶染色及电镜观察进行细胞纯度判断,未用差异贴壁去除成纤维细胞和IgG免疫黏附去除巨噬细胞纯化前,纯度达（70．4±4．8）％,纯化后可提高至（90．2±3．4）％;而用LPS干预ATⅡ,ATⅡ出现明显的细胞抑制。其中刺激浓度为1μg／ml时与其他3个实验组相比,细胞毒性反应最大（P〈0．01）,且在各个浓度的不同刺激时间里,4h时,细胞毒性反应最大（P〈0．01）。结论细胞分离后采用差异贴壁法和免疫黏附法进行纯化可使细胞纯度提高18％左右l细胞培养时接种密度达到1X107／ml以上有利于细胞的贴壁和生长,而用1μg／ml LPS刺激体外培养的大鼠ATⅡ4h能建立较为合理的内毒素性肺损伤细胞模型。     

两种果子狸血清IgG纯化方法的比较

目的探讨一种具有简便快捷、高纯度、活性好的果子狸血清IgG纯化方法。方法比较Hitrap Protein A亲和层析和PAGE电泳两种纯化法对果子狸血清IgG的纯化,用PAGE还原电泳和Western-Blot法对IgG作纯度鉴定。结果对Hitrap Protein A纯化的果子狸血清IgG,其活性虽好,但纯度不高;而非还原PAGE电泳所纯化的果子狸血清IgG不但纯度高(>95%)、并具有较强的免疫活性。结论非还原PAGE电泳法纯化果子狸血清IgG,是一种具有高纯度、免疫活性强的纯化方法。