CYTOTOXIC EFFECTS ON PLASMA-MEMBRANE OF HUMAN DIPLOID FIBROBLASTS - COMPARATIVE-STUDY OF LEAKAGE TESTS

  • 1 January 1976
    • journal article
    • research article
    • Vol. 54  (1) , 39-49
Abstract
Confluent monolayers of human diploid lung fibroblasts were treated with cytolytic agents. The induced membrane damage was investigated by different test systems. Changes of membrane permeability were compared with morphological alterations. Four tests employed leakage of cytoplasmic markers of different sizes as criteria of membrane damage. Radioactive markers of the following decreasing size order were used: [3H]RNA (MW > 200,000) > 51Cr > [3H]nucleotides > [1-14C].alpha.-aminoisobutyric acid (AIB, MW 103). Uptake of trypan blue was employed as a fifth criterion of changed membrane permeability. A comparison between the tests indicated the following order of sensitivity for detection of membrane damage: leakage of AIB-label > leakage of nucleotide label > leakage of 51Cr-label = uptake of trypan blue = morphological changes > leakage of RNA-label. Two distinct types of leakage patterns were evident: Upon incubation with Triton X-100 all four release curves coincided. This was considered as representing large functional holes. With the polyene amphotericin B the smallest marker (AIB) was released to a strikingly greater extent than other markers. This was regarded as representing very small functional holes. Melittin from bee venom and theta-toxin from Clostridium perfringens induced leakage patterns of 2 intermediate types. A combination of several different size markers may be useful for characterizing induced membrane lesions.