Probiotic Treatment Induces Neuroprotection in Hyperhomocysteinemia Mice after Ischemic Stroke
Authors: Mondal Nandan Kumar , Behera Jyotirmaya , Kelly Kimberly , Tyagi Neetu 
Published: June 2021

Hyperhomocysteinemia (HHcy) is characterized by an abnormally high level of homocysteine (Hcy) and is assumed as an independent risk factor for ischemic stroke. The severity of oxidative stress and neuronal damage are common observable facts during stroke. Studies have shown that the microbiome plays a significant role in brain functions like stress response and emotion‐driven behavior. Probiotic is the ‘good’ bacteria that are part of the microbiome, but the effect of probiotic treatment on ischemic stroke is unclear. Moreover, probiotics have been considered as an emerging source of antioxidants. Therefore, the objective of this study was to determine whether probiotic treatment can induce neuroprotection during ischemic stroke. In our study, we employed 8–10‐week‐old male/female cystathionine‐beta‐synthase heterozygote knockout (CBS+/−) mice (genetically hyperhomocystemic mice). The experimental groups were: (CBS+/−), (CBS +/− +Probiotics); (CBS+/− /I/R), and (CBS+/− /I/R+Probiotics). Mice in stroke (I/R) group were subjected to middle cerebral artery occlusion (MCAO) for 40 min, followed by reperfusion for 72 hours. Experimental mice were intragastrically treated with vehicle or the probiotics (GSL#5) for a period of 3 consecutive days after 3 hrs of stroke. We found that infarct size, brain edema, and permeability were increased in CBS+/− /I/R mice compared to control; however, probiotics treatment in ischemic mice reduces ischemic effects. The levels of NOX‐4 and MDA were significantly upregulated in CBS+/− /I/R mice when compared to controls. On the other hand, the levels of CAT, GPx, and endogenous H2S were significantly reduced in CBS+/− /I/R compared to control. Probiotic treatment ameliorated oxidative stress. Neuronal dysfunction was evaluated by measuring the levels of Neuronal nuclear antigen (Neun), Neuron‐specific‐enolase (NSE) and Fluoro‐jade C(FJC) fluorescence; while cerebrovascular disruption was evaluated by assessing levels of VE‐Cadherin and Claudin‐5 in harvested brain tissue. Cerebrovascular permeability was assessed by evaluating microvascular leakage of fluorescently‐labeled albumin in vivo. Nitric oxide synthase regulation (eNOS, nNOS) and vascular inflammation (ICAM) were also evaluated in brain tissue. Our experimental data showed that neuronal dysfunction (decreased NeuN levels and increased FJC positive neurons in the brain) was more prominent in CBS+/− /I/R mice compared to controls. In CBS+/− /I/R mice, the cerebrovascular disruption was found to be elevated as evident from increased microvascular leakage and decreased in VE‐Cadherin expression compared to controls. The decrease in nNOS and increase in eNOS suggest a trend towards the decrease in potential for neuronal development in stroke mice. In conclusion, probiotics treatment reduces oxidative stress, induces neuroprotection in hyperhomocysteinemia mice after ischemic stroke. This study suggests a potential therapeutic role of dietary probiotics in ischemia stroke.Support or Funding InformationThis work is financially supported by National Institute of health grant AR‐067667 and HL‐107640‐NT are greatly acknowledgedThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.