A murine cell line is a population of cells derived from a mouse that can be maintained and grown in a laboratory. The term “murine” indicates the mouse origin, while “cell line” refers to the propagation of these cells outside the organism. These cell cultures are tools in biology, providing a consistent and reproducible system for studying cellular processes in a controlled environment.
The Origin and Development of Murine Cell Lines
The creation of a murine cell line begins with isolating cells from mouse tissue, such as embryos, organs, or tumors. These initial cells, known as a primary culture, have a finite lifespan and will only divide a limited number of times before they stop growing in a process called senescence.
To become a cell line, these primary cells must undergo immortalization, which allows them to divide indefinitely. This can happen through a spontaneous mutation during cell culture or be deliberately induced through genetic modification, often by introducing genes that override the cellular aging process.
Once immortalized, the cells can be continuously passaged, where a small number of cells are transferred to a new culture dish with fresh nutrient medium to expand. This process results in a stable cell line that can be frozen for long-term storage, shared among researchers, and provide a large supply of genetically similar cells.
Function in Scientific and Medical Research
Mice are useful model organisms in medical research because their genetic and physiological systems have similarities to humans. Since many biological pathways are conserved between the species, murine cells are a relevant system for studying human health and disease. The ability to create genetically engineered mouse models also allows for deriving cell lines with specific genetic modifications.
In cancer research, murine cell lines are used to investigate how tumors develop and to test the effectiveness of potential anti-cancer drugs. This in vitro (in the lab) analysis helps identify promising therapeutic candidates before testing in living organisms.
These cell lines are also used in drug discovery and toxicology to screen new compounds for therapeutic effects and assess their safety at a cellular level. In developmental biology, cell lines from embryonic tissues help scientists understand how an organism develops from a single cell.
Prominent Examples of Murine Cell Lines
One widely used murine cell line is the NIH/3T3 line, established from Swiss mouse embryo tissue. NIH/3T3 cells are fibroblasts used in studies of cancer and gene function because they can be transformed into cancer-like cells and are efficient at taking up foreign DNA (transfection).
The C2C12 cell line is another example, derived from the thigh muscle of a C3H mouse. These cells are myoblasts, or muscle precursor cells. Under specific culture conditions, C2C12 cells can be induced to differentiate and fuse into myotubes, which are structures similar to muscle fibers, making them a useful model for studying muscle development and disease.
P19 cells are derived from a murine embryonic carcinoma, a type of germ cell tumor. A feature of P19 cells is their pluripotency, meaning they can be induced to differentiate into various cell types, including neurons, glial cells, and cardiac muscle cells. This versatility makes the P19 line a useful tool for research in developmental biology.
The Ethical Framework for Animal Cell Use
The use of animal-derived cells in research is governed by a set of ethical principles known as the Three Rs: Replacement, Reduction, and Refinement. This framework provides internationally accepted guidelines for the humane treatment of animals in science, and the principles are embedded in legislation and regulations worldwide.
- Replacement refers to methods that avoid or substitute the use of live animals in experiments wherever possible. This can include using computer models, human volunteers, or in vitro methods like cell culture.
- The principle of Reduction aims to minimize the number of animals used to obtain sufficient data. The use of established murine cell lines directly supports this goal. Once a cell line is created from a single animal source, it can be propagated indefinitely in the lab, providing material for countless experiments. This practice prevents the need to use new animals for each individual study.
- Refinement involves modifying procedures to minimize any potential pain, suffering, or distress to the animals.