Cardiotoxicity in rats following subchronic exposure to cadmium chloride solution and cadmium oxide nanoparticles

Abstract

Introduction A number of epidemiologic and experimental studies have demonstrated that cadmium exposure increases the risk of cardiovascular diseases. However, it has not been investigated so far whether the cardiotoxicity of cadmium ions and cadmium oxide nanoparticles are similar. Methods Subchronic cadmium poisoning was modelled on outbred white male rats by repeated intraperitoneal injections of cadmium chloride (CdCl 2 ) solution or cadmium oxide nanoparticles (CdO NPs) 3 times a week for 6 weeks. Single doses of Cd were 0.38 and 0.22 mg Cd per kg of body weight, respectively. Results In rats of both Cd-exposed groups were found signs of hepatotoxicity and nephrotoxicity accompanied by cardiotoxic effects manifested by changes in hemodynamic parameters and myocardial contractility. The force of contractions decreased while the muscle isometric contraction–relaxation cycle of isolated myocardial preparations shortened. The change in the maximum velocity of isotonic shortening of papillary muscles correlated with change in the content of α- or β-myosin heavy chains following the exposure to CdCl 2 or CdO NPs, respectively. In the NPs-exposed rats, the mechanical work performed by cardiac muscles was found to be decreased. Conclusions We established that moderate subchronic cadmium exposure weakened the pumping function of the heart due to the cardiotoxic effects at the cellular and molecular levels. At the same time, we observed not only quantitative, but also certain qualitative differences in the cardiotoxic effects of CdCl 2 and CdO NPs, probably associated with a more expressed oxidative stress induced by nanoparticles.

Keywords

• cadmium
• cardiotoxicity
• myocardium contractility
• myosin
• nanoparticles
• rats