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Muscle trophic factor: I. Assay of a muscle trophic factor by measurement of muscle cell nuclei
Author(s) -
Ozawa Eijiro,
Kohama Kazuhiro
Publication year - 1978
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880010308
Subject(s) - trophic level , myocyte , petri dish , biology , incubation , skeletal muscle , anatomy , andrology , chemistry , microbiology and biotechnology , biochemistry , ecology , medicine , genetics
Abstract A method for assaying a skeletal muscle cell trophic factor in chicken serum is described. The number of myoblast and myotube nuclei was considered to reflect the rate of myoblast multiplication and was thus adopted as an index for the activity of the trophic factor. In a 35‐mm Falcon plastic Petri dish, 2.5 × 10 4 to 10 5 myoblasts were cultured. The culture medium consisted of 85% Eagle's minimum essential medium and 15% horse serum. The assay medium was composed of 2.4 ml of this culture medium and 0.1 ml of partially purified trophic factor of appropriately diluted chicken serum. Four dishes were prepared for each sample under identical conditions. On day 4 of incubation, cells were fixed, stained, and observed under a microscope, and the number of nuclei in 20 fields was counted. The mean number of nuclei obtained from the four dishes was used to denote a single point. A three‐point common‐zero method of slope‐ratio assay was used to calculate activity. The activity of the trophic factor was expressed with reference to the effect of the control serum on myoblast multiplication.