| Pulmonary hypertension(PH) is a progressive, complex and often fatal condition. It is generally recognized that the common feature of all kinds of PH are continuing vasoconstriction and pulmonary arterial remodeling, both of which are closely related to the sustained elevation of calcium concentration in PASMCs. It has been confirmed that store-operated calcium entry is enhanced in both chronic hypoxia and monocrotaline induced PH rats, and which is the important reason for the cytoplasm calcium concentration increases. Furthermore, nuclear factor of activated T cells(NFATc) is also actived in both PH rats. This study further observed when the store-operated calcium entry was augmented in monocrotaline induced PH rats and the effect of NFATc indirect inhibitor cyclosporin A(Cs A) on store-operated calcium entry in two kinds of pulmonary hypertension rats in order to provide pathophysiological basis for it becoming targeted drug of PH.1. Cs A inhibited the development of two kinds of PH in rats.Objective: To observe the change of RVSP and RVMI with time in CH and MCT induced PH rats and the effect of cyclosporin A pretreatment in two different administration methods on RVSP and RVMI in these two experimental PH rats.Methods: ①Timecourse cruve of RVSP and RVMI were examined in PH rats induced by a single intraperitoneal injection of MCT at a dose of 50mg/kg and exposure to normobaric hypoxia respectively.②On the basis of Cs A pretreatment by intraperitoneal injection at 25mg/kg on every and alternate days respectively in above two time point PH rats and normal SD rats, we also examined the timecourse cruve of RVSP and RVMI.Results: ①RVSP and RVMI began to increase in a week after MCT injection, and it had significant increase in 2 and 3w compared wih normal level. Cs A pretreatment could partly inhibit the rise of them in the corresponding time point compared with saline-treated MCT induced PA rat. What’s more, the inhibitory effect of Cs A pretreatment on every day was more significant than every other day. ②RVSP was presented time-dependent rise in the early stage in CH and it attained the peak in 1w after exposure to normobaric hypoxia, then remained at this level. Pretreatment with Cs A could not suppress the elevation of RVSP in the early stage(within 5days) in CH but blunted RVSP increases in a week after hypoxic exposure, then remained at a lower level. ③In normal SD rats receiving Cs A, RVSP and RVMI did not change significantly in comparison with rats that received saline. Both of them had no statistical difference from normal level. ④RVMI was augmented with time in CHPH and pretreatment with Cs A blunted its increase.Conclusion: Cs A pretreatment inhibited the development of MCT and chronic hypoxia-induced PH model in terms of the timecourse curve of. Pretreatment with Cs A per day had a better inhibitory effect on RVSP and RVMI than alternate day. And the inhibiting effect on RVMI was more significant than RVSP in daily injection way, which indicated that intrinsic mechanism indepented of the PAP increase which determined the process of RV function may be existed. In the process of CHPH model formation, vasoconstriction may be an initiaing factor and interaction between vasoconstriction and remodeling may be existed in the late period.2. Cs A inhibited the increases of [Ca2+]i and SOCE in PASMCs from MCT and CH induced PH rats.Objective: To observe when the store-operated calcium entry was augmented in monocrotaline induced PH rats and the effect of Cs A pretreatment on store-operated calcium entry and [Ca2+]i in PASMCs of MCT and CH induced PH rats.Methods:On the basis of model building, we use: ①Isolation and primary culture of PASMCs. ②Measurement of [Ca2+]i by fluo-3 fluorescence, detecting the changes of Ca2+ transients induced by CPA. ③Mn2+ quenching of fura-2 fluorescence, detecting the changes of Ca2+ entry induced by CPA.Results: ①PASMCs were successfully cultivated and the purity was more than 95 percent by immunohistochemistry. ②The increases of [Ca2+]i and Ca2+ entry via store-operated calcium channel(SOCC) activated by CPA were augmented in 1w after MCT injection and more significant in 2 and 3w compared with normal level. In MCT induced PA rat receiving Cs A, these increases were reduced compared with rats that received saline. What’s more, Cs A daily injection had a trend of further suppression than injection on alternate days, but there were not statistic difference between the two groups. ③In normal SD rats receiving Cs A per day,the increases of [Ca2+]i and Ca2+ entry induced by CPA were mildly augmented compared with rats that received saline. ④The increment of [Ca2+]i and the function of Ca2+ entry via store-operated calcium channel(SOCC) activated by CPA were augmented in CHPH rats treated with saline, whereas a smaller increase in [Ca2+]i and Ca2+ entry via SOCC was observed in CHPH rats receiving Cs A.Conclusion: SOCE enhancement played a crucial role in the progression of MCT and CH induced PH. Pretreatment with Cs A partly prevented the enhanced SOCE function that occured in MCT and CH induced PH rats. However, in normal SD rats receiving Cs A per day, SOCE was mildly enhanced compared with rats receiving saline. |
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