What is the Difference Between Cell Viability and Cytotoxicity

Cell viability and cytotoxicity are two terms used in biology and biopharmaceutical industry. Both are distinct phenomena that evaluate cell health. They are important in fields like cell banking. Furthermore, cell-based assays have been used to assess the impact of drugs on cell viability and the drug’s cytotoxicity.

The key difference between cell viability and cytotoxicity is their nature. Cell viability refers to how many cells are alive and functioning in a population, while cytotoxicity refers to the ability of a substance like a drug or chemical to damage or kill cells.

CONTENTS

1. Overview and Key Difference
2. What is Cell Viability  
3. What is Cytotoxicity
4. Similarities – Cell Viability and Cytotoxicity
5. Cell Viability vs Cytotoxicity in Tabular Form
6. Summary – Cell Viability vs Cytotoxicity
7. FAQ – Cell Viability and Cytotoxicity

What is Cell Viability?

Cell viability is defined as the ability of cells to survive and maintain their physiological functions under specific conditions. Cell viability is a very important aspect of cell culturing, such as plant tissue culture, mammalian cell culture, and cell banking. Cell viability is also important in drug development, toxicity testing, and tissue engineering.

Figure 01: Cell Viability

Cell viability depicts the overall health and functional state of biological cells, so it provides important insights into their responses to external stimuli. Furthermore, cell viability assays are tests that use a variety of markers as indicators of metabolically active cells. These markers include measuring ATP levels, measuring the ability to reduce a substrate, and detecting enzymatic/protease activities.

What is Cytotoxicity?

Cytotoxicity is the property or ability of certain substances to cause damage or death to cells. It is a critical parameter in drug development, environmental testing, and assessing the safety of various materials. Generally, cytotoxicity occurs from exposure to chemicals, drugs, or other external factors that disrupt cellular processes and function and lead to cell death.

Figure 02: Cytotoxicity

Cytotoxicity assays are the tests used to measure the extent of cell damage caused by different compounds. Furthermore, cytotoxicity assays measure drug or chemical-induced alterations in metabolic pathways or structural integrity of the cells, which may or may not be directly related to cell death. The most common markers used for this type of assay are lactate dehydrogenase (LDH) and G6PD (glucose-6-phosphate dehydrogenase).

Similarities between Cell Viability and Cytotoxicity

1. Cell viability and cytotoxicity are two terms used in biology and biopharmaceutical industry.
2. Both are important in cell culturing and drug development.
3. They are often measured indirectly using particular markers in research.
4. Both can be assessed by using respective biochemical assays in the laboratories.

Difference Between Cell Viability and Cytotoxicity

Definition

1. Cell viability is the performance of cells on certain physiological functions, such as metabolism, growth, proliferation, response to external stimuli, and adaptation.
2. Cytotoxicity is the ability or property of a substance to damage or kill cells.

Measured

1. Cell viability is measured based on number of live or healthy cells in a sample.
2. Cytotoxicity is measured based on the number (relative or absolute) of dead cells.

Assays and Markers

1. Cell viability is assessed by viability assays by using markers such as ATP levels, ability to reduce a substrate, and enzymatic/protease activities.
2. Cytotoxicity is assessed by cytotoxicity assays by using markers such as LDH and G6DP.

Provide

1. Cell viability provides insights into cell health, growth, and function.
2. Cytotoxicity provides data on the safety and efficacy of drugs and chemicals.

Applications

1. Cell viability is an important parameter in culturing, as well as plant tissue culture, mammalian cell culture, cell banking, drug development, toxicity testing, and tissue engineering.
2. Cytotoxicity is an important aspect of drug development, environmental testing, and assessing the safety of various materials.

The following table summarizes the difference between cell viability and cytotoxicity.

Summary – Cell Viability vs Cytotoxicity

Cell viability and cytotoxicity are two important parameters often discussed in biology and the biopharmaceutical industry. Cell viability measures the proportion of viable cells in a population or sample, while cytotoxicity assesses the harmful effects of substances such as drugs or chemicals on cells. Furthermore, cell viability is commonly used for cell banking, optimizing cell culture conditions, and drug screening, whereas cytotoxicity is commonly used in toxicity testing and environmental monitoring. This is the summary of the difference between cell viability and cytotoxicity.

FAQ: Cell Viability and Cytotoxicity

1. How does one determine cell viability?

• Cell viability can be calculated using the ratio of total live or healthy cells to total cells (live and dead) in a sample. A staining procedure can facilitate the visualization of overall cell morphology.

2. What is good cell viability?

• Cell viability is an important aspect of culturing, especially in plant tissue culture, mammalian cell culture, cell banking, and drug development. 80-95% cell viability indicates a healthy cell culture.

3. What is the marker of cell viability?

• Viable cells with active metabolism are able to convert MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) into a purple-colored formazan product. This is because positively charged compounds (MTT) can readily penetrate viable cells. Thus, this color formation can be a useful marker of viable cells.

4. What are the reasons for cytotoxicity?

• Cytotoxicity is specifically the property of an agent that causes destructive action on cells. Compounds that are cytotoxic can result in multiple cell fates. Cytotoxic substances may induce cellular necrosis followed by cell lysis, inhibit cell growth and division, or activate apoptosis.

5. What is an example of a cytotoxin?

• One example of a potent cytotoxin that is produced by enteric pathogens is the Shiga toxin. It is produced by Shigella dysenteriae type 1 as well as by strains of STEC (Shiga toxin-producing E. coli). Shigella species can cause shigellosis, which is a bacillary dysentery.

Reference:

1. “Cell Viability – An Overview.” ScienceDirect.
2. Davey, Reginald. “What Is Cytotoxicity?” News – Medical, Life Sciences.

Image Courtesy:

1. “Laboratoorne pagaripärm (Saccharomyces cerevisiae) agariplaadil” By Rainis Venta – Own work (CC BY-SA 3.0) via Commons Wikimedia

2. “Drug danger and dependence-small” By user:Looie496, derived from original by user: Thundermaker – own work, derived from (CC BY-SA 3.0) via Commons Wikimedia

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