Hydrocephalus Following Experimental Subarachnoid Hemorrhage in Rats with Different Aerobic Capacity.

Yasunori Toyota,Lauren G Koch,Steven L Britton,Ya Hua,Fenghui Ye,Hajime Shishido,Guohua Xi,Hugh J L Garton,Richard F Keep

doi:10.3390/ijms22094489

Yasunori Toyota, Lauren G Koch + Show 7 more

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https://doi.org/10.3390/ijms22094489

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Abstract

Low aerobic capacity is considered to be a risk factor for stroke, while the mechanisms underlying the phenomenon are still unclear. The current study looked into the impacts of different aerobic capacities on early brain injury in a subarachnoid hemorrhage (SAH) model using rats bred for high and low aerobic capacity (high-capacity runners, HCR; low-capacity runners, LCR). SAH was modeled with endovascular perforation in HCR and LCR rats. Twenty-four hours after SAH, the rats underwent behavioral testing and MRI, and were then euthanized. The brains were used to investigate ventricular wall damage, blood–brain barrier breakdown, oxidative stress, and hemoglobin scavenging. The LCR rats had worse SAH grades (p < 0.01), ventricular dilatation (p < 0.01), ventricular wall damage (p < 0.01), and behavioral scores (p < 0.01). The periventricular expression of HO-1 and CD163 was significantly increased in LCR rats (p < 0.01 each). CD163-positive cells were co-localized with HO-1-positive cells. The LCR rats had greater early brain injuries than HCR rats. The LCR rats had more serious SAH and extensive ventricular wall damage that evolved more frequently into hydrocephalus. This may reflect changes in iron handling and neuroinflammation.

Highlights

Subarachnoid hemorrhage (SAH) is a common hemorrhagic stroke that results in striking morbidity and mortality
With rats bred to gain high and low aerobic capacities, we previously reported that low-capacity runner (LCR) rats exhibited worse brain damage than high-capacity runner (HCR) rats after intracerebral hemorrhage (ICH) [8,9]
Neuroinflammation is an important component of cerebral-hemorrhage-induced brain injury, including SAH [13], and we previously found that microglia activation was increased in LCR rats compared to HCR rats after experimental ICH [8]

Summary

Introduction

Subarachnoid hemorrhage (SAH) is a common hemorrhagic stroke that results in striking morbidity and mortality. Several studies have associated the incidence of SAH with cardiorespiratory fitness or physical activity. In a study involving a large sample of ethnically diverse patients (n = 67,550), good cardiorespiratory fitness was associated with a significantly lower hemorrhagic stroke incidence, including SAH [6]. Another populationbased study reported that commuting and leisure-time physical activity may reduce SAH risk in both men and women [7]. To our knowledge, no studies have investigated SAH-induced EBI in rats with respect to varied aerobic capacities. We examined the impacts of different aerobic capacities on early brain injury in a rat SAH model

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