In vitro and in vivo (cyto)toxicity assays using PVC and LDPE as model materials

Area of Science:

• Biomaterials Science
• Toxicology
• Cell Biology

Background:

• Biomaterial selection relies on cytotoxicity assays.
• Understanding assay parameters is crucial for accurate results.
• Standardized testing protocols are needed for reliable biomaterial evaluation.

Purpose of the Study:

• To evaluate the rationales behind selecting parameters for cytotoxicity assays.
• To compare in vitro and in vivo assay performance.
• To determine the optimal animal model for local toxicity assessment.

Main Methods:

• Cytotoxicity was assessed using in vitro direct contact and extraction assays with human epidermal keratinocytes and mouse fibroblasts/epithelial cells.
• Cell survival was measured via the tetrazolium salt (MTT) reduction assay.
• Local implantation studies were conducted in mice and rats using positive, negative, and experimental toxicity samples.

Main Results:

• Positive controls showed high in vitro toxicity, confirming extraction of toxic components.
• Direct contact assays with negative controls significantly reduced mouse fibroblast survival.
• In vivo studies revealed severe degeneration in mice with positive controls, while rats showed minimal changes.
• Experimental materials induced moderate responses in mice only.
• Mice were more sensitive than rats in detecting local toxic responses in vivo.

Conclusions:

• The direct contact assay provides limited additional cytotoxicity information without considering specific limitations.
• Mice are more suitable than rats for in vivo local toxicity detection.
• Careful selection of assay parameters and animal models is essential for accurate biomaterial safety assessment.