Cytotoxikus

Cytotoxikus (cytotoxic) describes substances, cells, or responses that are toxic to cells, causing damage or death. The term is used in biology, toxicology, and medicine to denote agents that impair cellular function through mechanisms such as DNA damage, membrane disruption, or interference with metabolism.

Cytotoxicity is encountered with chemotherapy drugs that kill rapidly dividing cells, environmental toxins, and radiation. It also describes the action of immune cells, notably cytotoxic T lymphocytes and natural killer cells, which destroy infected or cancerous cells by releasing perforin and granzymes.

Mechanisms of cytotoxicity include apoptosis, necrosis, and other forms of programmed cell death driven by mitochondrial pathways, caspases, oxidative stress, and DNA damage. The particular route depends on the agent, dose, and cell type.

Laboratories measure cytotoxicity with assays that assess cell viability or cell lysis, such as LDH release, MTT/MTS tests, annexin V staining, or chromium-51 release assays. These tests help evaluate potential drugs, toxins, and immune responses.

In practice, cytotoxicity informs cancer treatment planning, toxicology, and safety assessment. Clinically, the goal is to maximize tumor cell kill while minimizing harm to normal tissues, acknowledging side effects like cytopenias, mucositis, and organ toxicity.