Effects of dimethyl sulfoxide on the functionality of isolated rat aorta

Dimethyl sulfoxide (DMSO) is the solvent commonly used to dissolve hydrophobic drugs and widely used in research and medicine. In this study, the effects of DMSO on the functionality of vascular smooth muscle of isolated rat aorta in the presence and absence of endothelium were investigated. Thoracic aortic strips were isolated from male Wistar rats (250-300 g) and the contractile responses were measured isometrically, using force-displacement transducers. Our results showed that DMSO at high concentration (5% and 10% v/v) induced an initial transient contraction, followed by relaxation of the basal tone of aortic strip. DMSO had the complex effect on the aortic contraction evoked by various contractants. Low concentrations (0.0172% v/v) of DMSO did not have the effect on the contraction induced by noradrenaline, KCl, TEA and caffeine in physiological solution. Under the same condition, high concentration of DMSO (5% and 10% v/v) produced the oppositeeffects. However, the suppression was reversible upon removal of DMSO. The effect of DMSO did not depend on the presence of endothelium. Similary to the contraction induced by various contractants, DMSO only at high concentration inhibited the contraction induced by cumulative CaCl[subscript 2] in Ca[superscript 2+]-free depolarizing solution. Furthermore, DMSO at low concentration (0.03% and 0.07% v/v) inhibited the increase in the resting tone (IRT), but did not affect the subsequent contraction in Ca[superscript 2+]-free medium (NA2). Hence, DMSO did not affect the refilling of the intracellular Ca[superscript 2+] stores-sensitive to noradrenaline. In conclusion, low concentration of DMSO did not have the inhibitory effect on the contraction induced by various contractants, whereas DMSO at high concentrations inhibited the contraction under the same condition. In addition, DMSO had the vasorelaxation effect on the vascular tone.