Objective To investigate the role of intracellular Ca2+ and MERTK in the phagocytosis of human retinal pigment epithelial (RPE) cells, and reveal the relationship between MERTK and intracellular Ca2+. Methods The cultured RPE cells were incubated with rod outer segments (ROS) at 37℃, the phagocytosis was terminated at different incubation time points. The concentration of intracellular Ca2+ was assayed by Fluro-3/AM loading methods combined with fluorescence microscope and CCD system, and the mRNA level of MERTK gene was measured by reverse transcription polymerase chain reaction (RT-PCR). Treating the RPE cells with stimulator (A23187) or inhibitor (verapamile) of intracellular Ca2+ to observe the changes of MERTK gene expression. Results ROS adhered to hRPE cells at the 15th minute, and the ingestion saturated at the 24th hour. The concentration of intracellular Ca2+ increased at the 15th minute, and kept the high level in 24 hours. The level of MERTK mRNA increased at the 5th minute, and kept the high level duration the whole incubation. When RPE cells were treated by A23187, the expression of MERTK increased in a dose-dependent manner. After RPE cells was pretreated by A23187, the expression level of MERTK was higher in the proceeding incubation groups than which in the control group except at the 3rd hour. When RPE cells were treated by verapamil, the expression level of MERTK decreased in a dosedependent manner. After RPE cells were pretreated by verapamil , the expression level of MERTK was lower in all the proceeding incubation groups than which in the control group (Plt;0.05). Conclusion MERTK gene and Ca2+ play an important role in sustaining RPE cells phagocytizing ROS. As an up-stream regulator, the receptor tyrosine kinase MERTK keeps RPE cells phagocytizing ROS by starting the intracellular Ca2+.
【Abstract】ObjectiveTo compare the effects of newcastle disease virus (NDV) and adriamycin (ADM) on surface structure and actin of hepatocellular carcinoma cell lines SMMC-7721. Methods SMMC-7721 carcinoma cell lines were divided into 2 groups. NDV was added into one group, while ADM was added into the other group. The cells were then cultured at 5 time phases (8, 16, 24, 36 and 48 h). Intracellular actin and Ca2+ were examined by using immunofluorescence method. CD44 and intercellular adhesion molecule-1 (ICAM-1) were detected by using immunochemical method and flow cytometry, respectively. The change of cellular surface structure was observed by scan electron microscope. Results Cells gradually contracted and turned round over time. It was observed that actin was segmented and cells alignment became disordered. The mean fluorescence intensity of actin decreased in both groups, but it was obvious in NDV group. There were significant differences of fluorescence intensity between 2 groups at the phases of 16 h (P＜0.05), 24 h (P＜0.05), 36 h (P＜0.01) and 48 h (P＜0.05), except the one after 8 h. Intracellular Ca2+ concentration increased gradually in both groups, and the amplifications in NDV group were significantly higher at the phases of 24 h, 36 h and 48 h than those in ADM group (P＜0.01， P＜0.05 and P＜0.01, respectively). There were also differences at 8 and 16 h, but there were no statistical significance. The expression of CD44 in cells decreased. The mean fluorescence intensity of ICAM-1 raised gradually, and then came to peaking at 36 h, but there was no significant difference between two groups. All the above indices between different phases in the same group showed significant differences (P＜0.05). Conclusion Both NDV and ADM could make tumor cells degenerate and rupture, but the effect of NDV is more intensive. It could increase the fragility of cells and hasten the process of cell rupture. Disintegrated cancer cell and changes of adhesion molecule could lead cancer cells be identified, encapsulated, and killed by immune cells under static condition.
Objective To explore the activity of Ca2 + -activated K+ ( KCa) inairwaysmoothmuscle cells( ASMCs) in a rat model of chronic obstructive pulmonary disease( COPD) , and to observe the effect of 11, 12-Epoxyeicosatrienoic acid( 11, 12-EETs) on the KCa channel of ASMCs. Methods Forty male Sprague-Dawley rats were randomly assigned to a COPD group and a normal control group. The rats in the COPD group were exposed to cigarette smoking in a relatively closed chamber to induce COPD. The ASMCs were isolated from small bronchi using an acute enzymatic digestion method. In the symmetrical high K+ solution,the KCa currents were separated with inside-out configuration using the patch clamp technique. The activity of KCa currents in ASMCs between the COPD group and the normal group were compared and the effect of 11, 12-EETs on KCa channel was recorded. The opening probability( Po) , opening time( To) and closing time ( Tc) of the KCa were measured. Results Compared with the normal group, Po of KCa in the COPD rats was much shorter ( 0. 084 ±0. 028 vs 0. 198 ±0. 029, P lt; 0. 01) , To was shorter [ ( 0. 732 ±0. 058) ms vs ( 1. 648 ±0. 152) ms, P lt; 0. 01] and Tc was longer[ ( 12. 259 ±2. 612) ms vs ( 6. 753 ±1. 237) ms, P lt;0. 01] . 11, 12-EETs can evoke the activity of KCa currents of ASMCs in the COPD rats while Po was increased( 0. 227 ±0. 059 vs 0. 084 ±0. 028, P lt; 0. 01) , To was much longer[ ( 2. 068 ±0. 064) ms vs ( 0. 732 ±0. 058) ms, P lt; 0. 01] , and Tc was shorter [ ( 4. 273 ±0. 978) ms vs ( 12. 259 ±2. 612) ms, P lt;0. 01] .Conclusions The results suggest that the decreasing of KCa activity plays an important role in the development of COPD. 11,12-EETs can directly evoke the activity of KCa channel in COPD rats, thus relax the airway smooth muscles.
Myocardial stunning is the main pathological basis of heart dysfunction after open heart operation, its exact pathogenesis hasn’t been clarified until today.In recent years,the molecular and cellular studies have revealed possibly crucial pathogenesis of myocardial stunning that delayed recovery of myocardial glucose oxidation causes intracellular H + accumulation which augments H + Na + exchange thus leading to [Na +] i overload.[Na +] i overload increases Na + Ca 2+ exchange resulting in t...
We searched MEDLINE and The Cochrane Library to find high quality evidence aboutCa2＋ channel blocker in primary or secondary stroke prevention and summarized the avaliable evidence. The results show that in addition to the effect on hypertension, Ca2＋ channel blocker has antiartherosclerotic effect and can reduce the frequency rate of stroke. It has played an important role in primary stroke prevention. But concomitantly it can increase the risk of heart disease and as yet there is no evidence on secondary stroke prevention. Accordingly, Ca2＋ channel blockers should not be recommended as the first-fine medicine for stroke prevention.