Astaxanthin Nanoemulsion Pre-Supplementation Mitigates Ischaemic Stroke Injury by Enhancing Neuroprotection and Reducing Infarcted Volume Area

Ischaemic stroke is the third leading neurological disease that causes death around the world. One of the approaches to reduce severity after an ischaemic stroke is by preparing the brain for neuroprotection. Astaxanthin is a natural product produced by microalgae, Haematococcus pluvialis, against a harsh environment for its survival. It is a well-known carotenoid recognized for its anti-inflammatory and anti-apoptotic benefits. The advancements in nanomedicine of drug design and delivery systems suggest that formulating astaxanthin into a nanoemulsion could enhance its ability to penetrate the BBB and provide neuroprotection, including for ischaemic stroke injury. Rats were assigned to six groups: sham control (SCG), stroke (SG), stroke pretreated with palm olein (SOG), stroke pretreated with astaxanthin extract (SXG), stroke pretreated with astaxanthin macroemulsion (SMG), and stroke pretreated with astaxanthin nanoemulsion (SNG). Supplementation was given orally for 7 days before and once 3 hr after permanent middle cerebral artery occlusion (pMCAO). All groups were subjected to pMCAO for stroke induction except SCG, which received sham surgery. After twenty-four hr, the rats were tested for neurological tests and sacrificed for infarct volume and neuronal markers injuries quantification. This study demonstrated that pre-supplementation with astaxanthin nanoemulsion was able to minimize brain injury caused by ischemic stroke, as evidenced by a low modified neurological severity score, reduced percentage of failures between grids in the grid walking test, and increased latency on the rotarod in the rotarod test. Furthermore, pre- and post-supplementation of astaxanthin nanoemulsion demonstrated a reduction in neuronal cell death as shown by TTC staining and a reduction in neuro-ischemic markers, evidenced by a low level of S100β and NSE in the plasma. In summary, our findings suggest that astaxanthin nanoemulsion could be a promising approach in mitigating the effects of ischemic stroke.