Related Experiment Videos
Fibroblast growth in vitro suppressed by LPS-activated macrophages. Reversal of suppression by hydrocortisone
1Department of Oral Biology,School of Dental Medicine, Tel Aviv University, Israel.
Abstract:
Activated macrophages are among the major constituents of the periapical granuloma. Their state of activation may persist for long periods after the local irritant is removed and may delay resolution and repair of the lesion. The effect of activated macrophages on fibroblast growth was studied in vitro. Circular fibroblast colonies were formed using a drop containing 7.5 x 10(5) murine dermal fibroblasts and allowed to grow for 7 days. When peritoneal exudate macrophages were added (0.5-3.0 x 10(6) cells/dish) and activated in vitro by LPS (1 microgram/ml), the fibroblast colony's growth was suppressed. LPS alone, at the concentration used, had no effect on the fibroblast growth. Hydrocortisone (> or = 10(-7) M) totally reversed the suppression, when added either simultaneously with or 6, 24, or 48 h after the LPS. The efficacy of late hydrocortisone treatment suggests that its effect was through prevention of the expression of the LPS activation of the macrophages. These findings may provide a possible clue to a pharmacological modulation of the healing processes that occur in the periapical lesion once its infective source had been eliminated.
Insights
Activated macrophages in periapical granulomas can impede healing. Hydrocortisone effectively reversed this suppression, suggesting a potential therapeutic target for modulating lesion repair.
Area of Science:
- Immunology
- Cell Biology
- Oral Pathology
Background:
- Activated macrophages are key components of periapical granulomas.
- Persistent macrophage activation can delay lesion resolution and repair.
- Understanding macrophage-fibroblast interactions is crucial for periapical lesion healing.
Purpose of the Study:
- To investigate the in vitro effect of activated macrophages on fibroblast growth.
- To explore the potential of hydrocortisone in modulating macrophage-induced fibroblast suppression.
Main Methods:
- Murine dermal fibroblasts were cultured to form colonies.
- Peritoneal exudate macrophages were activated with lipopolysaccharide (LPS).
- The impact of activated macrophages and hydrocortisone on fibroblast colony growth was assessed.
Main Results:
- Activated macrophages significantly suppressed fibroblast colony growth.
- LPS alone did not affect fibroblast growth.
- Hydrocortisone completely reversed the suppressive effect of activated macrophages, even when administered hours after LPS activation.
Conclusions:
- Activated macrophages inhibit fibroblast growth, potentially delaying periapical lesion repair.
- Hydrocortisone demonstrates efficacy in reversing macrophage-mediated suppression, suggesting a role in modulating inflammatory responses.
- These findings offer insights into pharmacological strategies for enhancing healing in periapical lesions.