Effect of emulsified isoflurane on apoptosis of anoxia-reoxygenation neonatal rat cardiomyocytes

MicroRNA-21 mediates the protective role of emulsified isoflurane against myocardial ischemia/reperfusion injury in mice by targeting SPP1

Isoflurane has demonstrated to exert protective impacts against ischemia/reperfusion (I/R) injury in some organs. This research explored the role of emulsified isoflurane (EI) in myocardial I/R injury through the interaction with microRNA-21 (miR-21). The myocardial I/R injury mouse models established by coronary artery ligation were respectively treated with EI, miR-21 mimic/inhibitor or silenced secreted phosphoprotein 1 (SPP1) plasmids. Then, the pathology, fibrosis and cardiomyocyte apoptosis in mouse myocardial tissues were observed. Furthermore, the expression levels of miR-21, SPP1, oxidative stress indices, inflammatory factors and apoptotic proteins in mouse myocardial tissues were determined. The targeting relation between miR-21 and SPP1 was confirmed. MiR-21 was poorly expressed and SPP1 was highly expressed in myocardial I/R injury mice. EI treatment, elevated miR-21, or silenced SPP1 improved cardiac function and suppressed the oxidative stress, myocardial fibrosis, inflammatory reaction and cardiomyocyte apoptosis in myocardial I/R injury mice, thereby reliving the myocardial I/R injury. These therapeutic effects of EI were repressed by miR-21 inhibition. Additionally, SPP1 was targeted by miR-21. Results in our research indicated that miR-21 mediated the therapeutic effect of EI on myocardial I/R injury in mice by targeting SPP1. This study may provide a novel treatment strategy for myocardial I/R injury.

The Bioequivalence of Emulsified Isoflurane With a New Formulation of Emulsion: A Single-Center, Single-Dose, Double-Blinded, Randomized, Two-Period Crossover Study

Background: Emulsified isoflurane is a novel intravenous general anesthetic obtained by encapsulating isoflurane molecules into emulsion. The formulation of emulsion has been improved according to the latest regulations of the China Food and Drug Administration. This study was designed to compare the bioequivalence of the new and previous formulation emulsion of isoflurane.

Methods: In a single-center, single-dose, double-blinded, randomized, two-period crossover study, healthy volunteers received intravenous injection of 30 mg/kg of isoflurane with either previous formulation of emulsion isoflurane (PFEI) or new formulation of emulsion isoflurane (NFEI). Arterial and venous blood samples were obtained for geometric mean test/reference ratios of C_max, AUC_0-t, and AUC_0-∞, as well as their 90% confidence interval (CI90) as the primary outcome. The secondary outcomes were safety measurements such as vital signs, 12-lead electrocardiography, adverse effects, and laboratory tests; and anesthesia efficacy was assessed by Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) score, bispectral index (BIS), and loss/recovery of eyelash reflex.

Results: 24 subjects were eligible, of which 21 completed the whole experiment (NFEI n = 21, PFEI n = 23). Arterial geometric mean test/reference ratios of C_max, AUC_0-t, and AUC_0-∞ were 104.50% (CI90 92.81%–117.65%), 108.23% (94.51%–123.96%), and 106.53% (93.94%∼120.80%), respectively. The most commonly seen adverse effects for NFEI and PFEI were injection pain (38.1% vs. 34.8%), hypotension (19.0% vs. 13.0%), apnea (14.3% vs. 17.4%), and upper airway obstruction (14.3% vs. 13.0%). No severe adverse effect was observed. The effectiveness of general anesthesia was similar between the two formulations.

Conclusion: The CI90 of C_max, AUC_0-t, AUC_0-∞, NFEI, and PFEI were within the range of 80%–125%, suggesting bioequivalence between NFEI and PFEI. The safety and anesthesia effectiveness were also similar.

Emulsified isoflurane combined with therapeutic hypothermia improves survival and neurological outcomes in a rat model of cardiac arrest

Emulsified isoflurane (EIso), when introduced following cardiopulmonary resuscitation (CPR), significantly improves survival and neurological outcomes in a rat model of cardiac arrest (CA). The present study aimed to examine whether EIso combined with therapeutic hypothermia (TH) confers an additive neuroprotective effect. Adult male Sprague-Dawley rats that were subjected to return of spontaneous circulation (ROSC) after a 6-min asphyxia-induced CA were randomized to five groups: Sham group, control group under normothermic conditions, EIso group (4 ml/kg for 30 min under normothermic conditions), TH group (33°C for 2 h), and EIso plus TH group. Survival conditions and neurological outcomes were evaluated at 1 day and 7 days after ROSC. Animal survival rate at 7 days after ROSC was 30.7% in the CPR group, 60% in the EIso group, 63.6% in the TH group and 72.7% in the EIso plus TH group. EIso, TH and EIso plus TH yielded significant improvements in survival rates, neural deficit score and cognitive function, and ameliorated hippocampal CA1 region cell injury and apoptosis at 1 day and 7 days after ROSC compared with the CPR group. Combined therapy of EIso and TH was superior to EIso or TH alone, suggesting that combined EIso and TH treatment results in significant improvements in survival and neurological outcomes, and was more effective than independent EIso or TH treatment.