RESUMEN
Aim To investigate the effects of bigelovin on mouse model of imiquimod-induced psoriatic itch and its mechanism. Methods Psoriasis-like mouse model was established by applying imiquimod cream on the back skin of mouse. Psoriasis area and severity index, pathological changes, the expression levels of inflammatory factors and related molecular biological data were used as effect indicators. The changes of the above parameters were observed after administration of different concentrations of bigelovin. Then the possible mechanism of the effects was further analysed.Results Compared with the model group, bigelovin significantly decreased the symptoms of skin lesions and reduced the PASI score. Bigelovin alleviated epidermal thickening and reduced the expression of Ki67 in a dose-dependent manner. The expression levels of inflammatory factors were reduced in both skin and serum.The percentage of Th17 cells was reduced and the percentage of Treg cells was increased in the lymph node.In addition, bigelovin also inhibited the phosphorylation of P65 protein and significantly reduced the nuclear localization of P65, suggesting that bigelovin might inhibit the activation of P65 protein. Conclusions The effect of bigelovin on improving the signs and symptoms of imiquimod-induced psoriasis mice may be related to the inhibition of P65 protein phosphorylation in keratinocytes.
RESUMEN
To investigate the effects of isovitexin Ⅳ on transient outward potassium current in rat ventricular myocytes. In this study, MTT assay was used to investigate the safe range of isovitexin. The results showed that the IC₅₀ of the drug was in the range of 10-30 μmol•L⁻¹, and the drug concentration of 1-3 μmol•L⁻¹ for the patch clamp test was within the safe range. In addition, the single ventricular myocytes were obtained by single-enzymatic hydrolysis through aortic retrograde perfusion. The transient outward potassium current (Ito) of rat ventricular myocytes was guided and measured by whole-cell patch-clamp technique and the changes of current characteristics were recorded after isovite was applied. When the concentration of IV was less than 0.1 μmol•L⁻¹, there was no significant effect on Ito. However, with the increase in the concentration of IV (≥0.3 μmol•L⁻¹), the peak of Ito was decreased gradually, from (32.32±2.9) pA/pF to （25.83±4.3） pA/pF, 1 μmol•L⁻¹ IV and (19.51±3.5) pA/pF, 3 μmol•L⁻¹ IV respectively, with an inhibition effect in a concentration-dependent manner. In the range of 1-3 μmol•L⁻¹, IV down-regulated the I-V curve of Ito significantly. The activation curve showed that IV can enable the maximum half activation potential (V1/2) to move to the positive direction, and the V1/2 was increased from (19.59±1.6) mV to (22.81±1.7) mV and (28.86±1.4) mV at concentration of 1, 3 μmol•L⁻¹, meanwhile the activation curve moved to the right. However, the maximum half inactivating potential (V1/2) of the steady-state inactivation curve of Ito was significantly decreased from (－51.43±0.99) mV to (－61.81±1.3) mV with concentration of 1 μmol•L⁻¹ and (－71.50±1.4) mV with concentration of 3 μmol•L⁻¹. The inactivation time constant of recovery from inactivation (τ) was up-regulated significantly from (94.89±0.73) ms to (118.5±1.5) ms and (162.4±1.4) ms at concentration of 1, 3 μmol•L⁻¹ respectively. Meanwhile IV could enable the inactivation recovery curve to move to the right, which suggested that it can prolong the recovery time from inactivation of the transient outward potassium channel. In conclusion, isovitexin had a high inhibitory effect on Ito in rat ventricular myocytes.