Growing cells in the laboratory environment, by providing appropriate nutrients, temperature, growth factors and some other chemical substances is called as cell culture. Not only differentiated animal cells, but also stem cells can be cultured in laboratory in aseptic condition. These cultured stem cells can be differentiated into specific type of cell by adding or changing the composition of cell culture media.
Stem Cell Culture Method:
1. Human embryonic stem cells are first isolated by transferring the inner cell mass into plastic laboratory culture dish, which already contains a nutrient broth known as cell culture media.
2. The stem cells divide and spread over the surface of the culture dish. The inner surface of the dish is typically coated with treated mouse embryonic skin cells, because of the treatment these cells will not divide. These mouse embryonic skin cells are called as feeder layer, they provide sticky surface to which human embryonic stem cells can attach to grow and divide further in the cell culture dish.
3. Also, the feeder layer cell that is mouse embryonic skin cells release nutrients into the culture medium. Recently, scientists have begun to grow embryonic stem cells without the mouse feeder cells. This is very important discovery as this avoids the risk of transmission of viruses and other macromolecules which are present in the mouse cell into human embryonic cell.
4. After some days, the cell of the inner cell mass that is human embryonic cell proliferates and begins to crowd the culture dish. At this point, cells are removed gently from the culture dish and are plated into several fresh culture dishes.
5. The process of replating the cells is repeated many times and for many months and this process is called as subculturing.
6. Each subculturing of cells is also known as passage. After six months or more, the original few human embryonic stem cells will yield millions of embryonic stem cells.
7. Embryonic stem cells, which are proliferated in cell culture for six or more months without differentiation are known as pluripotent and appear genetically normal, without having any genetic mutations are referred to as embryonic stem cell line.
8. Once the cell lines are establishes, batches of newly formed cell line are frozen using liquid nitrogen and cryopreservation method and are shipped to other laboratories for further culturing and experimentation.
9. These human embryonic stem cell lines can be used to differentiate into specific form of cell like muscle cell, nerve cell, cartilage or any form of specific cell by altering the composition of cell culture media.
10. Scientists can differentiate this human embryonic cell line by adding growth factors to the media or by altering genes present in them.
11. Scientists and researchers are also trying to differentiate these human embryonic stem cells by introducing new genes into cells genome.
1. The most important and potential application of human stem cell is the generation of cells or tissues, which could be used for cell-based therapies. These cells or tissues will be immunologically and genetically identical to the patient, hence will not induce graft rejection in patients and also will reduce the intake of immunosuppressant drugs by patient with transplanted organs or tissues.
2. Stem cells, directed to differentiate into specific cell types, acts as renewable source of replacement cells and tissues to treat patient with diseases like Parkinson's and Alzheimer's diseases, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis, and rheumatoid arthritis.
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