ABSTRACT
To investigate the effects of ultrasound combined with microbubbles on intracellular Ca2+ homeostasis in carboplatin ( CBP )‐treated A549 cell and its possible mechanisms of inhibiting A549 cell line activity . Methods According to whether SonoVue was used or not ,and the different dose of CBP ,the groups A‐F were arranged as the ultrasound( US) group( group A ) ,the ultrasound combined with microbubbles ( USMB) group( group B) ,the low dose CBP ( 100 μg/ml) + US group( group C) ,the low dose CBP+USMB group( group D) ,the high dose CBP ( 200 μg/ml)+ US group ( group E) and the high dose CBP+USMB group( group F) .A549 cells were bathed and washed by a calcium‐free buffer , loaded with Ca2+ indicator fluo‐4 AM . Real‐time images were acquired using laser confocal microscopy . T he fluorescence intensity of intracellular calcium ion concentration ( [ Ca 2+ ] i ) in individual living cell was observed and the calcium overload was analyzed . Results After ultrasound irradiation ,the normalized fluorescence intensity of [ Ca2+ ] i increased rapidly ,then returned to a new homeostasis ( selected cells in groups A ,B ,E ,F ) or experienced a second calcium oscillation ( some cells in group C and D ) . All the selected cells in group B and some cells in group C and D exhibited superimposed oscillations . T he calcium overloading time in group D was longer than those of any other groups . Four cells in group A experienced delayed calcium oscillations . Compared with group A ,the selected cells in other groups exhibited a larger amplitude of calcium oscillation ( all P ＜ 0 .05 ) and the selected cells in group B and D exhibited calcium oscillation for a longer period of time( all P ＜0 .05) . Conclusions In the calcium‐free buffer ,US ,USMB , CBP+ US ,CBP + USMB are direct stimuli of calcium overload in A 549 cells . SonoVue ,CBP ,CBP +SonoVue are all synergistic stimuli of calcium overload in A 549 cells irradiated by ultrasound .US ,USMB and CBP may synergistically induce calcium release from intracellular store sites in A 549 cells . Calcium overload is a possible mechanism of ultrasound combined with microbubbles in assisting CBP chemotherapy .
ABSTRACT
Aim ToinvestigatetheeffectsofCa2+/calmodulin-dependent protein kinase Ⅱ inhibitor KN-93 on calcium overload-induced heart injury.Methods Thirty-twoisolatedratheartswererandomlydivided into the control group,KN-93 control group,calcium paradox group,and calcium paradox with KN-93 treat-ment group.Left ventricular pressure were recorded, and the heart function was evaluated by the left ventric-ular end-diastolic pressure (LVEDP ) and developed pressure (LVDP).Coronary flow (CF)were collect-ed,and lactate dehydrogenase (LDH)content was de-termined.Triphenyltetrazolium chloride staining was usedtomeasuretheinfarctsize.Results Compared with the control group,KN-93 at 2. 5 μmol·L-1 had no effects on coronary flow,cardiac performance and cell death at the end of perfusion in normal rats (P>0. 05 );The hearts of calcium paradox exhibited a de-crease in LVDP and CF,meanwhile an increase in LV-EDP,LDH,and infarct size of 18 ±7. 2% (P <0. 01).2. 5 μmol·L-1 KN-93 further increased the levels of LVEDP,LDH and infarct size (P<0. 01)in Ca2+paradoxical hearts,while it provoked the decline intheCFandLVDP(P<0.01).Conclusion The data demonstrates that KN-93 aggravates heart injury in calcium paradox,it also suggests that CaMKⅡ is in-volved in the Ca2+overload-induced heart injury.