Evaluation of the effect of 2-aminoethoxydiphenyl-borate on cardiac dysfunction in arsenic poisoning rats by stratified strain technique / 中华超声影像学杂志

Objective:To evaluate the effect of 2-aminoethoxydiphenyl-borate (2-APB) on cardiac dysfunction in arsenic poisoning rats by stratified strain technique.Methods:Thirty-two 12-week-old SD rats were randomly divided into control group ( n=8) and arsenic exposure group ( n=24). After 12 weeks of arsenic exposure, arsenic exposure group was divided into three groups: natural recovery group ( n=8), low-dose intervention group (n=8) and high-dose intervention group ( n=8). The rats were treated with 2-APB for 21 days. After the last administration, the routine parameters and the layered strain parameters were measured by ultrasonic instrument. Then the rats were killed and their blood and myocardial samples were obtained. The levels of serum creatine kinase isoenzyme (CK-MB) and lactate dehydrogenase (LDH) were tested, and the morphological changes of cardiomyocytes were observed by HE staining. Results:Left ventricular ejection fraction (LVEF), left ventricular short axis shortening (LVFS), global circumferential strain of subendocardial myocardium (GCS-endo), global circumferential strain of middle myocardium (GCS-mid), global circumferential strain of subepicardial myocardium (GCS-epi) and circumferential strain rate of left ventricular segments (SrC) in the natural recovery group were lower than those in the control group ( P<0.05), while serum CK-MB and LDH were higher than those in the control group ( P<0.05). Some ultrasonic parameters and biochemical indexes in the low and high dose intervention groups were improved in varying degrees compared with the natural recovery group ( P<0.05). The correlation between GCS-endo and CK-MB was the highest ( r=-0.931, P<0.05). Myocardial HE staining showed that the degree of myocardial cell swelling and necrosis were reduced, and erythrocyte exudation was reduced in the low and high dose intervention groups compared with the natural recovery group. Conclusions:The stratified strain technique can be used to evaluate the protective effect of 2-APB on cardiac dysfunction in arsenic poisoning rats, and GCS-endo may be one of its sensitive indexes.

Inhibition of temperature-sensitive TRPV3 channel by two natural isochlorogenic acid isomers for alleviation of dermatitis and chronic pruritus

Genetic gain-of-function mutations of warm temperature-sensitive transient receptor potential vanilloid 3 (TRPV3) channel cause Olmsted syndrome characterized by severe itching and keratoderma, indicating that pharmacological inhibition of TRPV3 may hold promise for therapy of chronic pruritus and skin diseases. However, currently available TRPV3 tool inhibitors are either nonselective or less potent, thus impeding the validation of TRPV3 as therapeutic target. Using whole-cell patch-clamp and single-channel recordings, we report the identification of two natural dicaffeoylquinic acid isomers isochlorogenic acid A (IAA) and isochlorogenic acid B (IAB) that selectively inhibit TRPV3 currents with IC50 values of 2.7 ± 1.3 and 0.9 ± 0.3 μmol/L, respectively, and reduce the channel open probability to 3.7 ± 1.2% and 3.2 ± 1.1% from 26.9 ± 5.5%, respectively. In vivo evaluation confirms that both IAA and IAB significantly reverse the ear swelling of dermatitis and chronic pruritus. Furthermore, the isomer IAB is able to rescue the keratinocyte death induced by TRPV3 agonist carvacrol. Molecular docking combined with site-directed mutations reveals two residues T636 and F666 critical for the binding of the two isomers. Taken together, our identification of isochlorogenic acids A and B that act as specific TRPV3 channel inhibitors and gating modifiers not only provides an essential pharmacological tool for further investigation of the channel pharmacology and pathology, but also holds developmental potential for treatment of dermatitis and chronic pruritus.

Effect of Sphingosine-1-Phosphate on Intracellular Free Ca2+ in Cat Esophageal Smooth Muscle Cells

A comprehensive collection of proteins senses local changes in intracellular Ca²⁺ concentrations ([Ca²⁺](i) and transduces these signals into responses to agonists. In the present study, we examined the effect of sphingosine-1-phosphate (S1P) on modulation of intracellular Ca²⁺ concentrations in cat esophageal smooth muscle cells. To measure [Ca²⁺](i) levels in cat esophageal smooth muscle cells, we used a fluorescence microscopy with the Fura-2 loading method. S1P produced a concentration-dependent increase in [Ca²⁺](i) in the cells. Pretreatment with EGTA, an extracellular Ca²⁺ chelator, decreased the S1P-induced increase in [Ca²⁺](i), and an L-type Ca²⁺-channel blocker, nimodipine, decreased the effect of S1P. This indicates that Ca²⁺ influx may be required for muscle contraction by S1P. When stimulated with thapsigargin, an intracellular calcium chelator, or 2-Aminoethoxydiphenyl borate (2-APB), an InsP₃ receptor blocker, the S1P-evoked increase in [Ca²⁺](i) was significantly decreased. Treatment with pertussis toxin (PTX), an inhibitor of G(i)-protein, suppressed the increase in [Ca²⁺](i) evoked by S1P. These results suggest that the S1P-induced increase in [Ca²⁺](i) in cat esophageal smooth muscle cells occurs upon the activation of phospholipase C and subsequent release of Ca²⁺ from the InsP₃-sensitive Ca²⁺ pool in the sarcoplasmic reticulum. These results suggest that S1P utilized extracellular Ca²⁺ via the L type Ca²⁺ channel, which was dependent on activation of the S1P₄ receptor coupled to PTX-sensitive G(i) protein, via phospholipase C-mediated Ca²⁺ release from the InsP₃-sensitive Ca²⁺ pool in cat esophageal smooth muscle cells.

Mechanism of beryllium sulfate-induced apoptosis in human embryonic lung fibroblast / 中国职业医学

OBJECTIVE: To investigate the effect of beryllium sulfate( BeSO_4) on apoptosis of human embryonic lung fibroblast( MRC-5 cell). METHODS: MRC-5 cells were cultured in vitro and randomly divided into 6 groups: a control group,a low-,medium- and high-dose BeSO_4 group,an antagonist group,and an activator group. The former 4 groups were given final concentrations of 0,1,10 and 100 μmol / L of BeSO_4,respectively. The combined treatment of BeSO_4and2-aminoethoxydiphenyl borate( 10 μmol / L final concentration) was used in the antagonist group. The combined treatment of BeSO_4 and inositol triphosphate( IP3)( 10 μmol / L final concentration) was used in the activator group. After 24 and48 hours of culture,the cells were harvested. The apoptosis of MRC-5 cells was detected by flow cytometry. The intracellular calcium ion( Ca~(2+)) was detected using laser scanning confocal microscope. Quantitative real-time polymerase chain reaction was used to detect the relative expression of IP_3RⅢ and B-cell lymphoma-2( BCL-2) mRNA and the protein expression of IP_3RⅢ and IP3 were detected by enzyme-linked immunosorbent assay. RESULTS: The apoptosis rates of cells in the 3 BeSO_4 dose groups at the time points of 24 and 48 hours were lower than those in the control group at the same time points( P < 0. 05). The apoptosis rate of the antagonist group was lower than those in medium-dose BeSO_4 group and control group at the same time points( P < 0. 05). At the time point of 48 hours,the apoptosis rate of the activator group was lower than that of control group( P < 0. 05) and higher than that of the medium-dose BeSO_4group( P < 0. 05). As for the Ca~(2+)concentration at time point of 24 hours,the low-dose BeSO_4 group was lower than the control group( P < 0. 05),and the high-dose BeSO_4 group was higher than the control group( P < 0. 05). The Ca~(2+)concentrations at time point of 48 hours in the medium- and high-dose BeSO_4 groups were lower than that in the control group( P < 0. 05). Compared with the medium-dose BeSO_4 group and control group at time points of 24 and 48 hours,the Ca~(2+)concentrations in the antagonist group decreased( P < 0. 05),while thoes of the activator group increased( P < 0. 05). The expression of BCL-2and IP_3RⅢmRNA in the 3 BeSO_4 groups,the activator and antagonist group were higher than those of the control group( P <0. 05). The expression of IP3 R Ⅲ protein at the time point of 24 hours in the medium-dose BeSO_4 group,the activator group and the antagonist group were lower than that of control group( P < 0. 05). The expression of IP_3RⅢ protein at the time point of 48 hours,the high-dose BeSO_4 group was lower than the control group( P < 0. 05); the activator and antagonist groups were higher than the medium-dose BeSO_4group( P < 0. 05). The expression of IP3 protein in the lowand medium-dose BeSO_4 groups and the activator group were higher than that in the control group( P < 0. 05). The expression of IP3 protein in activator group was higher than the medium-dose group( P < 0. 05). CONCLUSION: BeSO_4 might change the Ca~(2+)concentration and inhibite the apoptosis of MRC-5 cell through regulating the IP3 R / Ca~(2+)pathway,IP3 can improve the decrease of Ca~(2+)concentration in MRC-5 cells induced by BeSO_4.