In this video we demonstrate the preparation of E18 Cortical Rat Neurons.
In this video, we demonstrate the preparation of E18 cortical rat neurons. E18 cortical rat neurons are obtained from E18 fetal rat cortex previously dissected and prepared. The E18 cortex is, upon dissection, immediately dissociated into individual neurons. It is possible to store E18 cortex in Hibernate E buffer containing B27 at 4°C for up to a week before the dissociation is performed. However, there will be a drop in cell viability. Typically we obtain our E18 Cortex fresh. It is transported to the lab in ice cold Calcium free Magnesium free dissection buffer (CMFM). Upon arrival, trypsin is added to the cortex to a final concentration of 0.125%. The cortex is then incubated at 37°C for 8 minutes. DMEM containing 10% FBS is added to the cortex to stop the reaction. The cortex is then centrifuged at 2500 rpm for 2 minutes. The supernatant is removed and 2 ml of Neural Basal Media (NBM) containing 2% B27 (vol/vol) and 0.25% Glutamax (vol/vol) is added to the cortex which is then re-suspended by pipetting up and down. Next, the cortex is triturated with previously fire polished glass pipettes, each with a successive smaller opening. After triturating, the cortex is once again centrifuged at 2500 rpm for 2 minutes. The supernatant is then removed and the cortex pellet re-suspended with 2 ml of NBM containing B27 and Glutamax. The cell suspension is then passed through a 40 um nylon cell strainer. Next the cells are counted. The neurons are now ready for loading into the neuron microfluidic device.
Preparing E18 Fetal Rat Cortical Neurons for Compartmentalization
Before starting out, it is important to warm all necessary media and reagents to 37°C.
It is also important to sterilize everything that is used for preparing the cells (e.g., rubber bulbs, tube racks, media bottles, etc.), and that which is placed in the hood, by wiping down with 70% ethanol.
Note: the final concentration of cells is typically between 2.5 million cells/ml and 8 million cells/ml
Loading the cells
After the cells have been counted, it is time to load the cells in the device:
Cell densities can be varied depending on the application. However, seeding primary neurons at too low of a density typically leads to cell death. Depending on the incubator and the level of humidity, media may need to be changed in the devices every 2 to 3 days. When changing media, it is important after removing the media from the reservoirs, to never remove media from the main channels. Further, it is good practice to place fresh media in the top wells and allow some fresh media to flow through the device and into the main channels before filling up all the reservoirs.
Material Name | Tip | Company | Catalogue Number | Comment |
---|---|---|---|---|
NBM | medium | Invitrogen | 21103-049 | Neural Basal Media is obtained by Invitrogen under their Gibco line of cell culture reagents. |
E18 rat embryos | Animal | Obtained from pregnant Sprague Dawley Rats. The pregnant rat is sacrificed and the E18 fetal rat pups dissected to obtain the E18 fetal rat cortex. | ||
CMFM dissection buffer HBSS | buffer | ice-cold Calcium-free Magnesium-free dissection buffer HBSS based. | ||
15 ml Tube | Tool | BD Falcon | Falcon No. 352097 | Available through Fisher Scientific catalog number 14-959-70C |
0.25% Trypsin-EDTA | Reagent | Invitrogen | ||
37˚C water bath | ||||
Pasteur pipets | Fisher Scientific | glass | ||
DMEM | medium | Invitrogen | ||
FBS | Reagent | Invitrogen | serum, used at 10% in DMEM | |
centrifuge | set at 2500 rpm | |||
Trypan Blue | Invitrogen | for counting live/dead cells | ||
BD Falcon Cell Strainer 40 um | Tool | BD Falcon | Falcon cat# 352340 | Available through Fisher Scientific. Fisher catalog# 08-771-1 |
B27 | Reagent | Invitrogen | 17504-044 | B27 is a proprietary supplement available through Invitrogen under their Gibco line of cell culture reagents. |
Glutamax | Reagent | Invitrogen | 35050-061 | Glutamax is available through Invitrogen under their Gibco line of celll culture reagents. |