Cadmium administration affects circulatory mononuclear cells in rats

Area of Science:

• Immunotoxicology
• Environmental Health
• Cellular and Molecular Immunology

Background:

• Cadmium (Cd) is a toxic environmental contaminant with known effects on human peripheral blood mononuclear cells (PBMCs).
• Limited data exists on the in vivo impact of cadmium on circulatory mononuclear cells.

Purpose of the Study:

• To investigate the in vivo effects of a sub-lethal cadmium dose on rat peripheral blood mononuclear cells (PBMCs) and associated immune responses.
• To examine cadmium's impact on leukocyte levels, mononuclear cell distribution, and inflammatory cytokine expression in vivo.

Main Methods:

• Rats received a single intraperitoneal injection of 1 mg/kg cadmium.
• PBMC activity, leukocyte counts, and mononuclear cell distribution were assessed 48 hours post-injection.
• Gene expression and production of inflammatory cytokines (IL-1β, TNFα, IL-6, IFNγ, IL-17) were analyzed in PBMCs, both spontaneously and after ex vivo stimulation.

Main Results:

• Cadmium exposure increased total peripheral blood leukocytes but decreased PBMC numbers, with mononuclear cell accumulation in the lungs and increased CD11b expression.
• Cadmium altered inflammatory cytokine gene expression in PBMCs, increasing IL-1β mRNA while decreasing others, with a trend towards reduced spontaneous IL-6 release.
• Ex vivo stimulation showed cadmium exposure decreased IL-6 production in response to LPS but did not affect other cytokine responses.

Conclusions:

• A single in vivo exposure to cadmium significantly impacts immune cell dynamics, including redistribution and altered inflammatory gene expression in PBMCs.
• These findings highlight cadmium's immunomodulatory potential and contribute to understanding its effects as an environmental contaminant.