Development of a Modified Surgical Technique for Simulating Ischemic Cerebral Cortex Injury in Rats

Bifico Ameliorates Neurological Deficits After Ischemic Stroke in Mice: Transcriptome Profiling

BACKGROUND/AIM

Evidence suggests that gut microbiota can affect various neurological diseases, including stroke. Stroke patients have an increase in harmful gut bacteria and a decrease in beneficial bacteria. This increases intestinal permeability, increases the risk of infection, and even affects many inflammatory factors. While probiotics may affect stroke prognosis by improving the gut environment. This study aimed to investigate the effect of probiotic Bifico on the neural function in mice after focal cerebral ischemia and explore its mechanisms of action.

MATERIALS AND METHODS

A focal cerebral ischemia model was established in mice. Four weeks before modeling, animals were divided into three groups: Stroke plus Vehicle group, Stroke plus Pre-Bifico group and Bifico group. The infarct volume and neurobehaviors were evaluated. Whole-gene expression profiling was performed at different days after treatment (D1, D7, D14, D28) by RNA-seq. Differentially expressed genes (DEGs) were the processed for Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG). Some inflammation and immune related genes were screened and their expression was analyzed.

RESULTS

Compared to the Stroke plus Vehicle group and Bifico group, the infarct volume and neurological score were significantly reduced in the Pre-Bifico group. There were 2 DEGs at D1, 193 DEGs at D7, 70 DEGs at D28 between Stroke plus Pre-Bifico group and Stroke plus Vehicle group. For GO analysis, there were 139 significant terms at D7 and 195 at D28. For KEGG, there were 2 significant pathways at D7 and 9 at D28. Among 87 genes related to inflammation and immunity, 6 DEGs were identified. The expression of CCL9 was significantly elevated at most time points after stroke compared to the Stroke plus Vehicle group, while that of CCL6, CXCL10, CD48, CD72 and CLEC7A was highly expressed only in the recovery stage of stroke.

CONCLUSION

Oral pre-treatment with Bifico for 28 days can reduce cerebral infarction and promote recovery of neurological function in stroke mice, which may be ascribed to the regulation of immunity and inflammation in the brain.

A non-invasive real-time monitoring system for cytotoxic brain edema in post ischemic stroke based on near-field coupling

BACKGROUND

As a common secondary pathophysiological process in postischemic stroke (IS), cytotoxic brain edema (CBE) is an independent factor leading to poor prognosis of patients. Near-field coupling (NFC) technology has some advantages such as non-invasive, non-contact, and unimpeded penetration of the skull. In theory, it can reflect the difference between normal and edema tissues through the near-field coupling phase shift (NFCPS) in the electromagnetic wave transmission trait.

METHODS

Combining NFC detection principle and computer programming, we established a high-performance real-time monitoring system with functions such as automatic setting of measurement parameters, data acquisition, real-time filtering and dynamic waveform display. To investigate the feasibility of this system to detect CBE, a saline simulation experiment and a 24-hour real-time monitoring experiment after middle cerebral artery occlusion (MCAO) in rats were carried out.

RESULTS

The results of the saline simulation experiment showed that the change of NFCPS was proportional to the increase of the simulated edema solution, and the variation range of NFCPS was more than 9∘ after 5 ml injection. In the 24-hour monitoring after MCAO, the NFCPS of the experimental group showed an overall downward trend over time an average change of -17.7868 ± 1.6325∘ and the change rate gradually decreased. The 24-hour NFCPS in the control group fluctuates slightly around the initial value, which has no obvious upward or downward trend.

CONCLUSION

The intragroup and intergroup difference statistical analysis shows that NFCPS can effectively distinguish different intracranial pathophysiological states after IS. This work provides sufficient evidence and a technical basis for using NFCPS to monitor CBE in the future.

Excessive Expression of Microglia/Macrophage and Proinflammatory Mediators in Olfactory Bulb and Olfactory Dysfunction After Stroke

BACKGROUND/AIM

Olfactory dysfunction can be caused by stroke but the pathogenesis is still unclear. Previous studies have proved that olfactory dysfunction could be caused by microglia activation in the olfactory bulb and that middle cerebral artery occlusion (MCAO) may induce ipsilateral olfactory bulb microglia activation. This study aimed to explore the possible pathogenesis of ischemic stroke-induced olfactory dysfunction.

MATERIALS AND METHODS

We used a rat model of MCAO to simulate ischemic stroke. Olfactory function tests were performed using buried food test. The mRNA expression of olfactory marker protein (OMP), microglia/macrophage activation, and proinflammatory mediators were measured using reverse transcription-quantitative polymerase chain reaction.

RESULTS

Following MCAO, rats had poorer olfactory performance. In the olfactory bulb of the rats, the mRNA expression of OMP decreased and the mRNA expression of microglia/macrophage activation and proinflammatory mediators increased.

CONCLUSION

Ischemic stroke causes microglia/macrophage activation and promotes neuroinflammation in the olfactory bulb, causing olfactory dysfunction.

Soluble epoxide hydrolase inhibition enhances anti-inflammatory and antioxidative processes, modulates microglia polarization, and promotes recovery after ischemic stroke

BACKGROUND

Ischemic stroke triggers inflammatory responses and oxidative stress in the brain, and microglia polarization affects the degree of neuroinflammation. It has been reported that the inhibition of soluble epoxide hydrolase (sEH) activity protects brain tissue. However, the anti-inflammatory and antioxidative effects of sEH inhibition in the ischemic brain are not fully understood. This study aimed to investigate the effects of a selective sEH inhibitor, 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA), after ischemic stroke.

METHODS

Adult male rats with middle cerebral artery occlusion (MCAO) were administered with AUDA or a vehicle. Behavioral outcome, infarct volume, microglia polarization, and gene expression were assessed.

RESULTS

Rats treated with AUDA showed better behavioral outcomes and smaller infarct volumes after MCAO. After AUDA treatment, a reduction of M1 microglia and an increase of M2 microglia occurred at the ischemic cortex of rats. Additionally, there was an increase in the mRNA expressions of antioxidant enzymes and anti-inflammatory interleukin-10, and pro-inflammatory mediators were decreased after AUDA administration. Heme oxygenase-1 was mainly expressed by neurons, and AUDA was found to improve the survival of neurons.

CONCLUSION

The results of this study provided novel and significant insights into how AUDA can improve outcomes and modulate inflammation and oxidative stress after ischemic stroke.