可见,Transwell与侵袭实验之间并不能划等号,Transwell有多种应用,侵袭实验也有多种方法。所谓Transwell侵袭实验,其实是指将Transwell这一技术应用于肿瘤细胞侵袭研究的一种实验。由于其简单易行、重复性好,因而得到了越来越广泛的应用,但不能认为研究肿瘤侵袭只有Transwell一种方法。作者: DONT 时间: 2012-12-26 09:37
2.2 制备细胞悬液
① 制备细胞悬液前可先让细胞撤血清饥饿12-24h,进一步去除血清的影响。但这一步并不是必须的。
② 消化细胞,终止消化后离心弃去培养液,用PBS洗1-2遍,用含BSA的无血清培养基重悬。调整细胞密度至1-10×105,个人认为不要超过5×105。
具体实验时采用密度要自己摸索,因为不同细胞,其侵袭能力是不同的。个人经验,细胞量过多,穿过膜的细胞会过多过快,如果最后用计数法统计结果的话将难以计数;而过少的话,可能还没到检测的时间点,所有的细胞都已穿过,因此最少也要保证在收样的时候,上室内还要有一定量的细胞存在。
个人认为,对照组和处理尽量不要分开计数,因为细胞数目的差异会严重影响实验结果。如果需要对细胞预处理而不得不分开计数,那么计数一定要多重复几次,力求准确,尽量保证对照组和处理组细胞密度一致。
2.3 接种细胞
① 取细胞悬液100-200µl加入Transwell小室,不同公司的、不同大小的Transwell小室对细胞悬液量有不同要求,请参考说明书。24孔板小室一般200µl。
② 24孔板下室一般加入500µl含FBS或趋化因子的培养基,不同的培养板加的量有不同要求,具体请参考说明书。这里要特别注意的是,下层培养液和小室间常会有气泡产生,一旦产生气泡,下层培养液的趋化作用就减弱甚至消失了,在种板的时候要特别留心,一旦出现气泡,要将小室提起,去除气泡,再将小室放进培养板。
③ 培养细胞:常规培养12-48h(主要依癌细胞侵袭能力而定)。时间点的选择除了要考虑到细胞细胞侵袭力外,处理因素对细胞数目的影响也不可忽视。
以我的课题为例,我使用的药物不仅会抑制肿瘤细胞侵袭力,还对细胞增殖有明显抑制。我选择的药物浓度是用MTT筛选出的72h的IC50。用这个浓度处理细胞,24h内对细胞增殖并无明显抑制,但24h后,抑制作用就开始出现了。所以,用这个浓度来做Transwell,处理时间也必须限定在24h内,否则一旦药物抑制了细胞增殖或者诱导出凋亡,使处理组细胞数目少于对照组,那么就难以肯定穿过膜的细胞比对照组少,究竟是由于侵袭被抑制引起,还是处理后细胞数目本身就比对照组少而引起的了。
时间过长不可以,同样,过短也不行,因为细胞内会有一定量的MMPs储存,短时间内可能侵袭能力不会有太大改变。同时从药物被吸收进去,进而发挥作用,影响MMPs表达,到最后释放到培养基中,还需要一个过程。时间点的选择可尽量长点,也可选择多个时间点研究时间依赖效应,但前提是这个时间范围内细胞数目不能有明显变化。
另外,我看到细胞在小室内的形态不是正常培养贴壁的形态,而是圆形的,仍是悬浮时的形态,不过会聚集成团,所以看到细胞不正常贴壁也不要紧张,是正常现象
在培养过程中,膜下会逐渐有少量小气泡产生,这是正常现象,可不予处理,但我遇到过培养一段时间后,膜下出现了大气泡,幸亏及时发现,否则后果将非常严重。因此,个人建议,最好接种细胞后1-2h把培养板从培养箱里拿出来看看,确信没有大气泡产生。作者: DONT 时间: 2012-12-26 09:45
通过给细胞染色,可在镜下计数细胞
① 用棉签擦去基质胶和上室内的细胞
② 染色:常用的染色方法有结晶紫染色、台肦蓝染色、Giemsa染色、苏木精染色、伊红染色等。
个人推荐采用0.1%结晶紫染色,这种方法有如下优势:(1). 不需要固定细胞,直接染色即可。(2). 配制简单方便。(3). 染色后可以用33%醋酸脱色,将结晶紫完全洗脱下来,洗脱液可在酶标仪上570nm 测其OD值,间接反映细胞数。个人认为这是结晶紫染色最大的优势所在。因为,虽然经过准确的细胞计数,往往穿过膜的细胞数仍难以准确控制,可能某一批实验穿过的细胞会特别多,以致细胞成堆,这种情况下就难以计数了,这种情况下就可以用醋酸脱色后用酶标仪检测。使用结晶紫染色要注意,染色前要将膜风干,否则可能会染不上。
③ 细胞计数:我们使用的是Leica DC 300F正置显微镜进行观察和拍照,把Transwell小室反过来底朝上就可清楚看到小室底膜上下室侧附着的细胞。也有不少人用手术刀将膜切下后染色,再贴在玻片上,滴二甲苯,再盖上盖玻片,就可以长期保存,但是这样做小室就成了一次性的了,未免有点浪费。
取若干个视野计数细胞个数。论坛里一般采用3-5个视野,也有人用10个,都是随机选取,个人认为这样选择的视野带有很大的偶然性,也会掺进人为影响,特别是计数视野较少的时候。我选取16个视野,不是随机选择,而是有固定的位置。我们使用的显微镜所看到的视野的直径刚好是Chemicon公司的ECM550系列小室底面膜的直径的1/4。
Fig8
Matrigel invasion assays
Overview
Matirgel is considered as basement membrane and generated from EHS sarcoma. Matrigel contains not only basement membrane components (collagens, laminin, and proteoglycans)but also matrix degrading enzymes/their inhibitors and growth factors. Invasion of tumor cells into Matrigel has been used to characterize involvement of ECM receptors and matrix degrading enzymes which play roles in tumor progression.
Material
- Matrigel (Becton-dickinson)
- 24-transwell (Coster)
- Fibronectin(Sigma)
- Diff-Quick staining solution (Fischer Scientific)
Procedure
1. Thaw Matrigel at 4C overnight.
2. Dilute Matrigel (5mg/ml to 1 mg/ml) in serum free-cold cell culture media (RPMI1640, EMEM, DMEM, etc).
3. Put 100 ul of the diluted matrigel into upper chamber of 24-well transwell
4. Incubate the transwell at 37C at least 4 to 5 h for gelling.
5. Harvest cells from tissue culture flasks by Trypsin/EDTA.
6. Wash the cells 3 times with culture media (RPMI1640, EMEM, DMEM etc)containing 1 % FBS.
7. Resuspend the cells in media containing 1% FBS at a density of 10^6 cells/ml.
8. Gently wash gelled matrigel with warmed serum free-culture media.
9. Put 100 ul of the cell suspension onto the matrigel.
10. lower chamber of the transwell is filled with 600 ul of culture media containing 5 ug/ml fibronectin, as an adhesive subtrate.
11. Incubate at 37C for 20 to 24 h.
12. Remove transwells from 24-well plates and stained with Diff-Quick solution.
13. Scrape off noninvaded cells on the top of the transwell with a cotton swab.
14. Count invaded cells under a light microscope.
Troubleshooting
- Need to check batch of matrigel.
- Matrigel tends to form gel very quickly at room temerature, therefore, pipets and tips using in steps 2 and 3 have to be chilled at -20C prior to experiements.
- In our experience, matrigel would not make gel under a concentration of 1 mg/ml.
- If cell make aggregation during invasion assays, reduce the density of cell suspension (at step 7).
- Invasion assays can be performed for 36 to 40h.
Reference
Knutson, JR., Iida, J., Fields, GB, and McCarthy, JB.
Molecular Biology of the Cell, 7: 383-396, 1996.
链接: cuturl('http://www.dxy.cn/bbs/post/view?bid=66&id=850832&sty=3&keywords=Transwell')作者: DONT 时间: 2012-12-26 15:07
Thincert做侵袭实验的步骤
下面奉上用Thincert做侵袭实验的步骤(摘自《A quantitative cell migration assay using ThinCert™ cell culture inserts》,大家如需要,可用google搜之):
1. Prepare cell cultures according to standard cell culture procedures
2. Starve cells overnight in serum-free medium with 0.2 % BSA
3. Harvest cells and wash them twice in PBS
4. Resuspend cells in serum-free medium with 0.2 % BSA to an appropriate final cell concentration (e.g. 106/ml)
5. Place 24 well ThinCertTM cell culture inserts in the wells of a CELLSTAR® 24 well cell culture plate
6. Add 600 µl culture medium with or without chemoattractant to each well of the cell culture plate
7. Add 200 µl cell suspension to each cell culture insert
8. Incubate the cell culture plate for 3-24 h in a cell culture incubator at 37°C and 5 % CO2
9. Remove the cell culture medium from each well of the cell culture plate and replace it by 450 µl serum-free culture medium with 8 µM Calcein-AM
10. Incubate for 45 min in a cell culture incubator at 37°C and 5 % CO2
11. Remove the culture medium from the cell culture inserts
12. Transfer the cell culture inserts into a freshly prepared 24 well cell culture plate containing 500 µl prewarmed Trypsin-EDTA per well
13. Incubate for 10 min in a cell culture incubator at 37°C and 5 % CO2, agitate the plate from time to time
14. Discard the cell culture inserts and transfer 200 µl of the Trypsin-EDTA solution (now containing the migratory cells) from each well into a black flat bottom 96 well plate
15. Read fluorescence in a fluorescence plate reader at an excitation wavelength of 485 nm and an emission wavelength of 520 nm
cuturl('http://www.dxy.cn/bbs/post/view?bid=66&id=7459761&sty=3&keywords=Thincert')作者: DONT 时间: 2012-12-26 15:07
请问有没有知道 BD公司的Matrigel保质期有多长时间?(-20度保存)说明书上只说stable for a minimum of 3 months from day of shipment when stored at -20℃.我有-20℃存放两年的Matrigel(师姐留下来的)现在还能用吗?作者: moonlight45 时间: 2012-12-26 15:09
请问有没有知道 BD公司的Matrigel保质期有多长时间?(-20度保存)说明书上只说stable for a minimum of 3 months from day of shipment when stored at -20℃.我有-20℃存放两年的Matrigel(师姐留下来的)现在还能用吗?
2.4.1.1 MTT法
① 用棉签擦去基质胶和上室内的细胞
② 24孔板中加入500µl含0.5mg/ml MTT的完全培养基,将小室置于其中,使膜浸没在培养基中,37℃ 4h后取出。
③ 24孔板中加入500µl DMSO,将小室置于其中,使膜浸没在DMSO中,振荡10min,使甲臜充分溶解。取出小室,24孔板于酶标仪上测OD值。
擦去基质胶?细胞不是在胶这面吗,这样擦不就把细胞也擦掉了吗
我也想知道怎样测量细胞迁移试验时迁移的距离,用软件还是在显微镜上直接可测?
我这有一篇文章就是测细胞迁移距离的,原文描述如下:
Cultures were fixed and the distance of cell migration away from
the edge of the fragment was analyzed. The maximum
distance of the leading edge of cells was measured in
each experiment, and the number of cells migrated from
the edge of the coverslip was counted within 50-mm
rows.
请指点。作者: DONT 时间: 2012-12-26 17:27
这个迁移实验是用Transwell做的吗?作者: DDD 时间: 2012-12-26 17:28
chemotaxis experiments in modified multiwell Boyden chambers (Neuroprobe, Gaithersburg, Md.) using nitrocellulose micropore filters (Sartorius, Go¨ttingen, Germany)
were performed as previously described .
After mounting of dehydrated filters to microscope slides migration depth of DC into the filter was quantified by microscopy, measuring the distance (mm) from the upper
surface of the filter to the leading front of five cells,before any cells had reached the lower surface (leading front assay) [21].
大侠,这是原文中的一部分,现在我在北京问了很多代理,买不到modified multiwell Boyden chambers ,我觉得测距离可能和modified multiwell Boyden chambers 有关,看能否帮忙知道具体怎么弄吗?那modified multiwell Boyden chambers和transwell是一个东西吗?谢谢您的帮助!作者: is2011 时间: 2012-12-26 17:28
请教一下,结晶紫染色不固定的话怎么染啊?具体步骤是什么样?除了风干膜以外还需要注意什么吗?作者: DONT 时间: 2012-12-26 17:29