Beneficial effects of (RS)-glucoraphanin on the tight junction dysfunction in a mouse model of restraint stress

The purpose of this work is to evaluate the effects of (RS)-glucoraphanin, a glucosinolate present in Brassicaceae, notably in Tuscan black kale, and bioactivated with myrosinase enzyme (bioactive RS-GRA) (10mg/kg intraperitoneally), and to assess its capacity to prevent the dysfunction of the blood-brain barrier (BBB), a fundamental structure for brain homeostasis, in a mouse model of restraint stress.

CD1 mice were subjected to restraint stress by blocking the body with a tape on a table for 150 min at the four extremities. After the sacrifice of the animals, stomachs and brains were collected to perform histological evaluation, Evan's blue dye, immunohistochemistry and western blotting analysis, to evaluate whether immobilization stress leads to alterations of tight junction (TJ) components, such as claudin-1, claudin-3 and ZO-1.

Immobilization causes considerable damage to BBB as shown by detection of Evan's blue dye, indicating a high level of extravasation due to stress. BBB alterations were accompanied by an enhancement of GFAP expression, IkB-alpha degradation followed by increased NF-kBp65 nuclear translocation, as well as caspase 3 overexpression. Conversely, our results revealed that bioactive RS-GRA treatment significantly counteracts the changes in all these parameters and preserves TJ integrity reducing the production of pro-inflammatory cytokines, such as TNF-α and IL-1β, and increasing the production of IL-10, an anti-inflammatory cytokine. Additionally, bioactive RS-GRA shows antioxidant properties modulating iNOS and nitrotyrosine expression.

Our results clearly show that bioactive RS-GRA could represent a possible treatment during pharmacological therapy of stress.