Stochastic simulation of notch signaling reveals novel factors that mediate the differentiation of neural stem cells

miR-34a overexpression protects against hippocampal neuron damage caused by ketamine-induced anesthesia in immature rats through the Notch-1/NF-κB signaling pathway

OBJECTIVE

To investigate the protective effect of miR-34a overexpression on hippocampal neuron damage caused by ketamine-induced anesthesia in immature rats and the underlying mechanism.

METHODS

A total of 48 male SD rats were divided into control group (CG, n=12), ketamine group (KG, n=12), negative control group (NCG, n=12), and intervention group (IG, n=12) by using the random number table method. Neurological function, cognitive function, pathological changes of brain tissues, inflammatory cytokines, as well as mRNA expression levels of Notch-1, NICD, RBP-JK, and Hes-1 in brain tissues were detected in the four groups.

RESULTS

The scores of auricular, paw withdrawal, corneal reflex, and escape reflexes of IG were higher than those of KG and NCG (P<0.05). At day 3 after intervention, the escape latency, time of staying in the quadrants of original platform, and times of crossing the quadrants of original platform of IG were lower than those of KG and NCG (P<0.05). HE staining results revealed that the morphology and structure of a few neurons and glial cells in IG were changed, and the intercellular space was increased. The brain tissues of NCG demonstrated marked neuron damage with unclear structure; these changes were less significant for KG. The levels of TNF-α, IL-1β, and IL-6 of IG were lower than those of KG and CG (P<0.05).

CONCLUSIONS

miR-34a overexpression exhibited a potent protective effect on hippocampal neuron damage caused by ketamine-induced anesthesia in immature rats.

Osthole inhibits proliferation of kainic acid‑activated BV‑2 cells by modulating the Notch signaling pathway

Epilepsy is a syndrome involving chronic recurrent transient brain dysfunction. Activation and proliferation of microglia serve important roles in epilepsy pathogenesis and may be targets for treatment. Although osthole, an active constituent isolated from Cnidium monnieri (L.) Cusson, has been demonstrated to improve epilepsy in rats, its underlying mechanism remains to be elucidated. The present study investigated the effect of osthole on proliferation of kainic acid (KA)‑activated BV‑2 cells and explored the molecular mechanism by which it inhibited their proliferation. Using Cell Counting Kit‑8, enzyme‑linked immunosorbent assay, reverse transcription‑quantitative PCR, western blot analysis and immunofluorescence staining, it was identified that following exposure of KA‑activated BV‑2 cells to 131.2 µM osthole for 24 h, cell proliferation and release of tumor necrosis factor α, interleukin 6 and nitric oxide synthase/induced nitric oxide synthase were significantly inhibited (P<0.05). Further experiments revealed that osthole significantly downregulated mRNA and protein levels of Notch signaling components in KA‑activated BV‑2 cells (P<0.05). Therefore, it was hypothesized that osthole inhibited the proliferation of microglia by modulating the Notch signaling pathway, which may be useful for the treatment of epilepsy and other neurodegenerative diseases characterized by Notch upregulation.