1. Low Concentration

• Non-toxic Levels: The concentration of DMSO used might have been below the toxic threshold for your specific cell type. Generally, DMSO concentrations up to 0.1–1% are well-tolerated by many cell lines, though this can vary.

2. Cell Type Specificity

• Cell Line Resistance: Some cell types are more resistant to DMSO than others. Certain cancer cell lines or stem cells might tolerate higher concentrations without undergoing cell death.
• Protective Mechanisms: Some cells may activate protective mechanisms, such as stress response pathways, to reduce DMSO-induced damage.

3. Time of Exposure

• Short Exposure: If the exposure time to DMSO was short, there may not have been enough time for it to reach concentrations that cause significant cell damage or death.
• Recovery Time: Cells may recover if they were exposed to low concentrations of DMSO for a short period and then allowed to recover in fresh medium.

4. Temperature and pH Conditions

• DMSO can have different effects depending on the temperature or pH of the medium. If the medium was kept at a temperature or pH that stabilized the cells, they might have been less affected by the solvent.

5. DMSO's Cryoprotective Effect

• DMSO is often used as a cryoprotectant in cell freezing because it prevents ice crystal formation. At low concentrations, it might protect cells from damage rather than kill them, especially if it wasn’t used for freezing but as a solvent.

6. Cell Confluence

• Cells that are in a low-confluence state (not tightly packed) or in a logarithmic growth phase might be more resistant to stressors like DMSO, whereas confluent or post-confluent cells are often more sensitive to solvents.

7. DMSO’s Mechanism of Action

• While DMSO can damage cells by disrupting cell membranes or interfering with cell signaling, its effects depend on the concentration, exposure time, and the specific cellular mechanisms involved. Some cells can repair or cope with mild DMSO-induced damage.

8. Presence of Protective Agents

• If you used other agents, such as antioxidants or protease inhibitors, these could have mitigated the toxic effects of DMSO and protected your cells from death.
• 9. Something else, there are many more Reasons...