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[Diphenhydramine interferes with MTT reduction assay]

Yao Shen1, Chen-Hui Zhang, Wei-Wei Hu

  • 1School of Biology Science, Wenzhou Medical College, Wenzhou 325035, China.

Zhejiang Da Xue Xue Bao. Yi Xue Ban = Journal of Zhejiang University. Medical Sciences
|April 14, 2011
PubMed
Abstract

Insights

Organic amines like diphenhydramine can falsely increase results in cell viability studies using the MTT assay. This occurs by inhibiting formazan exocytosis, not by affecting cell proliferation or death.

Area of Science:

  • Cell Biology
  • Biochemistry
  • Pharmacology

Context:

  • The 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay is widely used to assess cell viability.
  • Organic amines are common compounds with diverse biological activities.
  • Understanding assay interference is crucial for accurate biological research.

Purpose:

  • To investigate the impact of the organic amine diphenhydramine on the MTT reduction assay in primary cortical astrocytes.
  • To differentiate between true changes in cell viability and assay artifacts induced by diphenhydramine.
  • To explore the mechanism by which diphenhydramine influences MTT assay outcomes.

Summary:

  • Diphenhydramine, pyrilamine, and zolantidine significantly increased MTT reduction in astrocytes at specific concentrations.
  • No evidence of increased proliferation, apoptosis, or necrosis was observed via Hoescht and PI staining.
  • Light microscopy indicated that diphenhydramine inhibited the exocytosis of formazan granules.

Impact:

  • Diphenhydramine and other organic amines may artifactually enhance MTT reduction by inhibiting formazan exocytosis.
  • This interference can lead to inaccurate interpretations of cell viability in studies involving these compounds.
  • Highlights the importance of validating MTT assay results with complementary methods, especially when using potential interfering agents.

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