Short-term Effects of Cadmium Exposure on Blood Pressure and Vascular Function in Wistar Rats

Chronic cadmium exposure is known to be associated with vascular changes and increased blood pressure, but its short-term effects on the cardiovascular system remain poorly understood. This study aimed to investigate the pressoric and vascular effects of a 7-day exposure to CdCl₂ in Wistar rats. The rats were divided in control group (Ct), which received tap water, and the Cd group, which received a 100 mg/L CdCl₂ solution via drinking water for 7 days. We analyzed body weight, plasma Cadmium concentration, systolic blood pressure (SBP), and vascular responses. Despite relatively low plasma Cadmium concentration, the Cd group exhibited elevated SBP and increased contractile response to phenylephrine. Endothelium removal and NOS inhibition increased contractions in both groups. In the Cd group's aorta, we observed enhanced levels of phospho-eNOS (Ser¹¹⁷⁷⁾ and basal NO release. Cd group showed reduced Catalase expression and increased basal release of H₂O₂, with catalase reducing the contractile response. In arteries pre-contracted with phenylephrine, Cd group showed impaired endothelium-dependent (Acetylcholine) and independent (sodium nitroprussiate-SNP) relaxation responses. However, responses to SNP were similar after pre-contraction with KCl in both groups. These data suggest early effects of Cadmium on blood pressure and aortic function, indicating impaired H₂O₂-scavenging by catalase. Increased H₂O₂ due to Cadmium exposure might explain heightened responses to phenylephrine and weakened relaxation responses mediated by the NO-K⁺-channels pathway. Our findings shed light on Cadmium's short-term impact on the cardiovascular system, providing insights into potential mechanisms underlying its effects on blood pressure regulation and vascular function.