Apolipoprotein C3-rich low-density lipoprotein (AC3RL) increases BBB permeability and deteriorates cerebral ischemic stroke injury

Abstract

Abstract Background Ischaemic stroke causes disability due to brain damage resulting from blood supply obstruction or increased permeability of the blood-brain barrier (BBB) that exposes the blood to toxic substances during reperfusion. Apolipoprotein C3 is a crucial triglyceride transport modulator, and its overexpression raises the risk of dyslipidemia and cardiovascular disease. Clinically, we observed that stroke patients have higher levels of apolipoprotein C3-rich low-density lipoprotein (AC3RL) expression than healthy individuals, and they also have worse prognoses. Simultaneously, we found that an increase in AC3RL is involved in endothelial cell apoptosis and inflammatory response, which may be linked to the occurrence of brain injury after stroke. Purpose This study aimed to explore whether the high expression of AC3RL would increase the permeability of the blood-brain barrier, and aggravate brain damage. Methods The intraluminal monofilament model of middle cerebral artery occlusion (MCAO) experiment was carried out using C57BL/6 and apolipoprotein E gene knockout mice (ApoE-/-). WT receive an IV injection of AC3RL, which was separate from stroke patients' plasma. APOE-/- was fed a high-fat diet to promote AC3RL higher expression. We performed 60-minute ischaemic and 7-day reperfusion. The modified neurological severity score (mNSS) method was used to assess motor and neurological scores. Evans blue dye was injected through the tail vein one hour before euth (A) AC3RL, which was separated from stroke patients' plasma. (B) AC3RL concentration in individuals. (C) The white portion of the mice brains TTC stain indicates the site of the injury. (D) Evans blue dye leakage study in mice brains exhibited BBB permeability changes. (E) Assessment of mice's motor and neurological performance using the mNSS. anasia to assess BBB permeability. TTC staining of brain tissue after euthanasia to pinpoint the site of brain damage. Results Evans blue dye leakage was observed in the brain tissues of the group with high AC3RL expression, indicating that the BBB permeability has expanded. The mNSS method revealed a significant rise in mice with high levels of AC3RL expression, which suggested a decline in motor and nervous function. Conclusions Whether endogenous or exogenous, increased expression of AC3RL leads to more severe cerebral ischemic injury and motor dysfunction, which we believe may be due to increased BBB permeability caused by AC3RL. Therefore, AC3RL can be used as a disease predictor in the future, reducing AC3RL will be the main indicator for reducing severe brain injury.Figure 1.Figure 2.