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Comparative particle-induced cytotoxicity toward macrophages and fibroblasts
V Olivier1, J L Duval, M Hindié
1UMR CNRS 6600, University of Technology of Compiègne, Compiègne, France.
Abstract:
The cytotoxicity caused by the debris resulting from wear of prostheses can produce major damage to tissues around the implant. We have compared particle internalization by macrophages and fibroblasts in vitro and analyzed cell death. J774.2 macrophages and L929 fibroblasts were incubated with 0.43 and 2.81 microm alumina particles or 0.45 and 3.53 microm polystyrene (PS) beads. Incubation of J774.2 cells with alumina particles of both sizes and 0.5 and 1.0 mg/ml PS beads significantly decreased cell numbers in a particle concentration-dependent manner. L929 cells were not affected by lower concentrations of 0.43 microm alumina particles (which aggregate at high concentrations) and they internalized 0.45 microm PS beads without any decrease in cell numbers. Particles were more cytotoxic for macrophages than for fibroblasts. Particles caused the size of both types of cells to increase in correlation with cytotoxicity. Trypan blue exclusion and lactate dehydrogenase release showed cell membrane leakage for both types of cells incubated with PS beads for 24 h. Apoptosis was assessed by annexin V-FITC, propidium iodide staining and assay of caspase 3 activity. Macrophage death appeared to depend on both necrosis, caused mainly by 3.53 microm PS beads, and apoptosis, mainly due to 0.45 microm PS beads. The release of the inflammatory cytokine IL-6 appears to be nonlinearly correlated with cytotoxicity. Thus, the size of the internalized particles affects macrophages and fibroblasts differently, and the increase in cell size can be used as a preliminary criterion of particle cytotoxicity in vitro.
Insights
Prosthetic wear debris causes cytotoxicity. Macrophages are more sensitive than fibroblasts to particle cytotoxicity, with cell size increase indicating damage. Particle size influences cell death mechanisms.
Area of Science:
- Biomaterials Science
- Cell Biology
- Immunotoxicology
Background:
- Wear debris from medical prostheses can cause significant tissue damage around implants.
- Understanding cellular responses to particulate debris is crucial for improving implant longevity and patient outcomes.
Purpose of the Study:
- To compare the in vitro internalization of alumina and polystyrene particles by macrophages and fibroblasts.
- To analyze the cytotoxicity and cell death mechanisms induced by these particles in different cell types.
Main Methods:
- J774.2 macrophages and L929 fibroblasts were incubated with varying sizes and concentrations of alumina and polystyrene particles.
- Cell viability was assessed using trypan blue exclusion and lactate dehydrogenase release assays.
- Apoptosis was evaluated through annexin V-FITC, propidium iodide staining, and caspase 3 activity assays.
Main Results:
- Macrophages showed significantly decreased cell numbers with increasing particle concentration, unlike fibroblasts.
- Macrophages exhibited higher cytotoxicity compared to fibroblasts, with cell size increase correlating with damage.
- Cell membrane leakage was observed in both cell types after 24-hour incubation with polystyrene beads.
- Macrophage death involved both necrosis and apoptosis, influenced by particle size and type.
Conclusions:
- Particle size significantly impacts cytotoxicity and cell death pathways in macrophages and fibroblasts.
- Macrophages are more susceptible to the cytotoxic effects of wear debris than fibroblasts.
- Increased cell size serves as a potential preliminary indicator of particle-induced cytotoxicity in vitro.