Researchers from Japan have kept small portions of mouse brain tissue alive and viable for a period of 25 days, isolating in a culture. This has highly increased the timeline in which the isolated brain tissue can keep the functions intact extending days to weeks. This can affect the research in therapeutic drugs in a positive way. The findings have been published in the Analytical Sciences journal.
The key to success was a new technique that combines a special kind of membrane with an improved microfluidic device. Microfluidic devices use small channels for delivery of fluid into tissues and are better than the normal culture dishes specially for ex vivo tissue experiments. They can also be customized highly and mimic certain kinds of cell behaviors. They also require small volume samples thus making it easy to study the cell interactions.
However, only a few days is not sufficient to understand how body systems react to various things. The main problem is to keep a balance. Tissues dry quickly so the system has to be kept moist along with nutrients in a wet culture medium. Too much moisture prevents cells to exchange gases which the tissue needs thus drowning it finally. This problem had to be tackled by the researchers.
This device has a semi-permeable microfluidic channel that is surrounded by an artificial membrane and solid walls. These are made from polydimethylsiloxane, a polymer mainly used in microfluidic devices. The tissue does not sit in the bath consisting of the culture medium but instead, the fluid circulates through the channel, passing by the membrane to keep the tissues most while still maintaining the exchange of gases between cells.
Nobutoshi Ota, a biochemist at RIKEN Center for Biosystems Dynamics Research said that the medium flow was difficult to be controlled as the microchannel between the porous membrane and PDMS walls were not normal. The team got success after repeated trials and modifications to the membrane while adjusting the flow rates of the inlet and outlet.
A small part of the brain named suprachiasmatic nucleus(SCN) was used which is responsible for keeping the circadian and biological rhythms intact in mammals. Neuronal cells in SCN exchange information by keeping the motion of peptides and molecules between cells intact. This is ideal for studying cell interactions.
The mice from where the SCNs were harvested had been edited genetically such that the circadian rhythm in the brain was connected to the production of a fluorescent protein indicating if everything was working properly.
The fluorescence was active for 25 days compared to that of a normal culture dish where after 10 hours the activity control reduced by 6 percent. The experiment lasted for only 25 days since it was the cutoff time for this experiment. It could have lasted well beyond 100 days.
Researchers believe that this can also be used for remaining organ tissues with the possibility for human organs that are grown in the laboratory. This will improve the research in organogenesis by culturing and observation which is needed for the growth of organs and tissue.
Journal Reference: Analytical Sciences