Myocytes and fibroblasts exhibit functional synergism in mixed cultures of neonatal rat heart cells

Abstract

Cardiac cells obtained from neonatal rat heart contain a mixed population of cell types that can be enriched in culture in either myocytes or fibroblast-like cells. A metabolic comparison of mixed heart cell cultures with enriched cultures of the same age-in-culture and initial cell density showed that mixed cultures used glucose more rapidly than either enriched myocytes or fibroblasts. Mixed cultures were shown to respond to deprivation of insulin and of serum with decreases in the rate of glucose usage and decreases in the protein content of cells, whereas enriched cultures did not respond in the expected manner to insulin deprivation. Mixed, 11-day-old cells also exhibited greater increases in cellular protein and greater resistance to the stress of starvation than enriched cultures. Palmitate usage, however, was similar in all cultures examined. We conclude that mixed cultures may serve as a better model system to study cardiac metabolism and to monitor the effects of drugs and hormones on the neonatal myocardium. In addition, it is clear from our results that myocytes and fibroblastic-like cells coexist in a metabolically functional synergism.

Neonatal rat heart cells cultured in simulated microgravity

“…Cardiac cells were prepared from two or three day neonatal rats as previously described (6,20). Briefly, cells were liberated using a mixture of purified enzymes, inoculated onto fibronectincoated tissue culture plastic, and maintained in a defined serum free heart medium (SFHM), based on that previously (6,12) with high glucose medium substituted for the standard low glucose medium.…”

“…A key indication of contractile activity in cultured cardiac cells is altered energy metabolism (6,19,20). Accordingly, we measured specific enzymatic activities in HARV and control cultures.…”