Behavioral, electrophysiological and neuropathological characteristics of the occurrence of hypertension in pregnant rats

Salidroside prevents gestational hypertension-induced impairment of offspring learning and memory via Wnt/Skp2 pathway

BACKGROUND

Salidroside (Sal) has been found to protect against multiple impairments caused by diabetes, and we designed this study to investigate the effect of Sal on gestational hypertension (GHP)-induced impairment of offspring learning and memory.

METHODS

We established a GHP rat model by intraperitoneal injection of NG-nitro-L-arginine methyl ester (L-NAME), and treated with Sal by daily gavage. We used Morris Water Maze test to evaluate the learning and memory ability of offspring rats. HE staining was used to measured the pathological changes in hippocampus of offspring. Immunohistochemistry, cellular immunofluorescence and western blot were used to detect the protein expression.

RESULTS

The learning and memory abilities of GHP offspring rats were significantly lower than those of normal rat offspring, while Sal treatment could significantly improve the learning and memory abilities of GHP offspring rats. HE staining did not reveal pathological differences in the hippocampus of normal rats, GHP rats and Sal-treated GHP offspring rats. However, Sal treatment can significantly increase the expression of Wnt1 and Skp2 protein, and decrease the expression of P27kiwf and P21waf1 protein in the hippocampus of GHP offspring rats. In vitro, Sal significantly promoted the proliferation and differentiation on neural stem cell, while Wnt1 knockdown could reverse these promotions by Sal. In the hippocampus of GHP offspring rats, Sal treatment significantly increased the expression of Tuj1, SOX2, Ki67 and DCX protein.

CONCLUSION

Salidroside significantly improves the learning and memory impairment of offspring caused by GHP, and its mechanism may be related to the fact that Salidroside promotes the proliferation and differentiation of neural stem cells by activating the Wnt1/Skp2 signaling pathway.

Amazon rainforest rodents (Proechimys) are resistant to post-stroke epilepsy

There are no clinical interventions to prevent post-injury epilepsy, a common and devastating outcome after brain insults. Epileptogenic events that run from brain injury to epilepsy are poorly understood. Previous studies in our laboratory suggested Proechimys, an exotic Amazonian rodent, as resistant to acquired epilepsy development in post-status epilepticus models. The present comparative study was conducted to assess (1) stroke-related brain responses 24-h and 30 days after cortical photothrombosis and (2) post-stroke epilepsy between Proechimys rodents and Wistar rats, a traditional animal used for laboratory research. Proechimys group showed smaller volume of ischemic infarction and lesser glial activation than Wistar group. In contrast to Wistar rats, post-stroke decreased levels of pro-inflammatory cytokines and increased levels of anti-inflammatory mediators and growth factors were found in Proechimys. Electrophysiological signaling changes assessed by cortical spreading depression, in vitro and in vivo, showed that Wistar's brain is most severely affected by stroke. Chronic electrocorticographic recordings showed that injury did not lead to epilepsy in Proechimys whereas 88% of the Wistar rats developed post-stroke epilepsy. Science gains insights from comparative studies on diverse species. Proechimys rodents proved to be a useful animal model to study antiepileptogenic mechanisms after brain insults and complement conventional animal models.

Hippocampal network dysfunction as a mechanism of early-onset dementia after preeclampsia and eclampsia

Preeclampsia is a hypertensive disorder of pregnancy that can involve dangerous neurological symptoms such as spontaneous seizures (eclampsia). Despite being diseases specific to the pregnant state, preeclampsia and eclampsia have long-lasting neurological consequences later in life, including changes in brain structure and cognitive decline at relatively young ages. However, the effects of preeclampsia on brain regions central to memory and cognition, such as the hippocampus, are unclear. Here, we present a case reporting the progressive and permanent cognitive decline in a woman that had eclamptic seizures in the absence of evidence of brain injury on MRI. We then use rat models of normal pregnancy and preeclampsia to investigate mechanisms by which eclampsia-like seizures may disrupt hippocampal function. We show that experimental preeclampsia causes delayed memory decline in rats and disruption of hippocampal neuroplasticity. Further, seizures in pregnancy and preeclampsia caused acute memory dysfunction and impaired neuroplasticity but did not cause acute neuronal cell death. Importantly, hippocampal dysfunction persisted 5 weeks postpartum, suggesting seizure-induced injury is long lasting and may be permanent. Our data provide the first evidence of a model of preeclampsia that may mimic the cognitive decline of formerly preeclamptic women, and that preeclampsia and eclampsia affect hippocampal network plasticity and impair memory.