I'll start working with kg1a cells. after the cell passage, the apoptotic occupations are not removed, gradually their number in the environment increases and they cause problems. How could you get rid of the apoptotic occupations?
If yes, then you may eliminate the dead cells from culture by collecting the cell suspension containing both the live and dead cells in the centrifuge tube, and centrifuge at low speed (100g for 10 mins). The live cells will form a pellet at the bottom of the centrifuge tube, and the dead cells and debris can be removed by discarding the supernatant. This is because the dead cells are fractured and therefore the dead cells and debris are lighter than live cells and will remain in the supernatant.
If you are observing a buildup of apoptotic cells after cell passage in your KG1a cell line, there are several steps you can take to remove them and maintain a healthy culture:
Gentle centrifugation: After cell passage, you can try a gentle centrifugation step to remove the apoptotic cells. Centrifuge the cell suspension at a low speed (e.g., 200-300 x g) for a short duration (e.g., 5 minutes). This should pellet the healthy cells at the bottom while leaving behind the apoptotic cells in the supernatant. Carefully remove the supernatant without disturbing the cell pellet, and then resuspend the cells in fresh culture medium.
Differential adhesion: Another approach is to utilize the differential adhesion property of healthy and apoptotic cells. Allow the cell suspension to settle in a culture dish or flask for a short period (e.g., 30 minutes to 1 hour). During this time, healthy cells will adhere to the surface, while apoptotic cells will remain in the suspension. Carefully aspirate the supernatant containing the apoptotic cells and replace it with fresh medium.
Filtration: If the apoptotic cells are relatively larger in size compared to healthy cells, you can consider filtering the cell suspension through a cell strainer or a mesh filter with an appropriate pore size. This will retain the healthy cells while allowing the apoptotic cells to pass through, effectively removing them from the culture.
Trypan blue exclusion staining: Trypan blue is a vital stain that selectively stains dead cells. After cell passage, mix the cell suspension with an equal volume of trypan blue solution and incubate for a few minutes. Then, perform a cell count using a hemocytometer or an automated cell counter. The trypan blue dye will stain the apoptotic cells, making them distinguishable from viable cells. Exclude the trypan blue-stained cells from your cell count and subsequent culturing.
Apoptosis inhibitors: If you consistently observe a high level of apoptotic cells even after employing the above methods, you may consider using apoptosis inhibitors in your culture medium. These inhibitors can help reduce the apoptotic cell population. Commonly used apoptosis inhibitors include Z-VAD-FMK and Q-VD-OPh, among others. Follow the recommended concentration and treatment duration provided by the supplier.