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Effects of prolonged incubation of rat peritoneal mast cells with compound 48/80
F Levi-Schaffer1, N Riesel-Yaron
1Department of Pharmacology, School of Pharmacy, Hebrew University-Hadassah Medical School, Jerusalem.
Abstract:
Rat peritoneal mast cells (MC) co-cultured on a monolayer of 3T3 fibroblasts (MC/3T3) were continuously exposed to compound 48/80 for 14 days. As early as 2 days following continuous exposure to compound 48/80, the MC/3T3 appeared as a heterogeneous population, with various MC appearing partially or fully degranulated or intact; this morphological pattern continued throughout the duration of the experiment. MC/3T3 remained functionally active as demonstrated by their ability to secrete histamine 15 min after each replacement with fresh medium containing compound 48/80, although this capacity diminished towards the end of the 14-day experiment. Concomitant with the histamine release, a significant increase in cellular histamine pools was observed. When MC/3T3 continuously exposed to compound 48/80 for 7 or 14 days were acutely challenged with anti-IgE antibodies, they were able to secrete histamine and prostaglandin D2 in amounts similar to those produced by control MC. In contrast, when these cells were challenged on day 7 or 14 with a higher dose of compound 48/80 or with substance P, the release of histamine was partially inhibited. Our results indicate that continuous in vitro exposure to compound 48/80, and the resulting MC degranulation product histamine, does not adversely affect the ability of MC/3T3 to synthesize histamine and to respond to activation stimuli of a related secretagogue for 7 days and a non-related one for at least 14 days.
Insights
Continuous exposure to compound 48/80 in mast cells (MC) and 3T3 fibroblasts did not impair histamine synthesis or response to stimuli. Mast cells maintained functional activity despite degranulation.
Area of Science:
- Immunology
- Cell Biology
Background:
- Mast cells (MC) play a crucial role in allergic responses.
- Compound 48/80 is a known mast cell degranulator.
- Understanding mast cell adaptation to chronic stimulation is vital.
Purpose of the Study:
- To investigate the long-term effects of continuous compound 48/80 exposure on rat peritoneal mast cells.
- To assess mast cell function, histamine synthesis, and response to various stimuli after prolonged degranulation.
Main Methods:
- Co-culture of rat peritoneal mast cells with 3T3 fibroblasts (MC/3T3).
- Continuous exposure of MC/3T3 to compound 48/80 for 14 days.
- Assessment of mast cell morphology, histamine release, and prostaglandin D2 production upon stimulation with anti-IgE, compound 48/80, and substance P.
Main Results:
- Continuous compound 48/80 exposure led to heterogeneous mast cell populations with varying degranulation states.
- Mast cells maintained functional activity, releasing histamine upon stimulation, although capacity diminished over time.
- Cells retained the ability to synthesize histamine and respond to anti-IgE and substance P, but showed partial inhibition to higher doses of compound 48/80.
Conclusions:
- Continuous in vitro exposure to compound 48/80 does not permanently impair mast cell histamine synthesis.
- Mast cells can adapt to chronic degranulation, maintaining responsiveness to certain stimuli for extended periods.
- These findings offer insights into mast cell resilience and adaptation mechanisms in response to inflammatory triggers.