Involvement of galectin-3 in cadmium-induced cardiac toxicity

Objective: Accumulation of the wide spread environmental toxin cadmium (Cd) in tissues results in toxicity. Heart is one of the most effected tissues. Cd exposure induces inflammation in effected tissues. The present study was focused to evaluate roles of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) in Cd toxicity and their relationships with galectin-3 levels. Methods: In this experimental study, male Wistar rats were divided randomly to control and experimental groups. Experimental group was exposed to Cd at the dose of 15 ppm for 8 weeks (n=10/group). Inflammatory status in hearts was evaluated with measurement of tissue TNF-α and IL-6 levels. Histopathological examination of heart was carried out by light microscopy. Heart tissue caspase-3 level was used to identify apoptosis. Tissue galectin-3 level was evaluated by ELISA. Statistical difference between groups was evaluated by unpaired Student t-test, correlation was analyzed by Pearson’s test. Results: Heart sizes were increased after Cd toxicity. A significant increase in galectin-3 tissue levels was seen after Cd toxicity, this was accompanied with a significant increase in the TNF-α (control: 402±39, Cd: 793±26 pg/g tissue, p 0.001) and IL-6 (control: 150±78, Cd: 325±65 pg/g tissue, p 0.001) levels. Histopathological examination under light microscope suggested a combination of ongoing necrosis and apoptosis. Increased caspase-3 levels were measured after Cd toxicity (control: 12±2, Cd: 18±3 pmol/μg/min, p 0.001). Conclusion: Chronic Cd administration induces inflammation and apoptosis in rat hearts. Cadmium causes increased galectin-3 production from heart tissue. The formation of TNF-α due to Cd exposure may likely trigger this mechanism.