Erythropoietin diminishes isoflurane-induced apoptosis in rat frontal cortex

MiR-191 downregulation protects against isoflurane-induced neurotoxicity through targeting BDNF

BACKGROUND

Isoflurane inhalation can cause nerve damage, and miR-191 is abnormally expressed in nerve crush injuries. This study aimed to explore the effect of miR-191 on isoflurane-induced cognition impairment and neurotoxicity in vivo and in vitro, as well as its potential mechanism.

METHODS

Sprague-Dawley male rats and primary hippocampal neurons were applied and exposed to 2% isoflurane. The level of miR-191 was regulated both in vitro and in vivo to investigate the role of miR-191 in isoflurane-induced neurotoxicity. Morris water maze assay was used to evaluate the neurological function of rats. The level of miR-191 was measured by qRT-PCR. CCK-8 assay and Flow cytometry were applied to detect the cell viability and apoptosis. Dual luciferase reporter gene detection was used for the target gene analysis.

RESULTS

miR-191 was up-regulated in the hippocampal tissues of rats exposed to isoflurane. Downregulation of miR-191 ameliorated isoflurane-induced cognition impairment, including the increase of the neurological score and the escape latency, and the decrease of the time spent in the original quadrant for the rats exposed to isoflurane. Isoflurane exposure inhibited hippocampal neuron viability and promoted cell apoptosis, which was reversed by down-regulation of miR-191. BDNF is a target gene of miR-191.

CONCLUSIONS

Isoflurane causes some neurotoxic effect which is mediated through miR-191 abnormal expression targeting BDNF. Downregulation of miR-191 has a protective role against isoflurane-induced neurotoxicity, regulates the vitality and slows down neuronal cell apoptosis.

Downregulation of microRNA-448 improves isoflurane-induced learning and memory impairment in rats

The present study aimed to investigate the potential role of microRNA‑448 (miR‑448) in isoflurane-induced learning and memory impairment in rats. Sprague‑Dawley rats were used for the construction of isoflurane‑treated models. The Morris water maze test was used to evaluate the effects of isoflurane on rats regarding the following para-meters: Swimming speed, escape latency and time in original quadrant. Influences of isoflurane on neuron apoptosis and miR‑448 expression in rat hippocampus tissue were analyzed by flow cytometry and reverse transcription‑quantitative polymerase chain reaction, respectively. Furthermore, the effects of miR‑448 on the expression of cell apoptosis‑associated proteins were investigated by flow cytometry. The results demonstrated that isoflurane treatment induced higher escape latency and lower time spent in original quadrant compared with the control rats. In addition, isoflurane treatment induced neuron apoptosis and miR‑448 was highly expressed in the hippocampal tissue of isoflurane‑treated rats. Furthermore, Bcl‑x was significantly downregulated while caspase‑3 expression was upregulated by an miR‑448 inhibitor. Combined the results of the current study indicate that miR‑448 knockdown may have pivotal roles in improving isoflurane-induced learning and memory impairment via suppressing neuron apoptosis.