Thymoquinone-Loaded Hexosomal Nanoparticles Attenuate Neuroinflammation and Improve Cognitive Function in an Alzheimer’s Disease Mouse Model

Nermin Eissa,1,* Jana K Alwattar,2,* Petrilla Jayaprakash,3 Haya Al Assaly,1 Roua Kharnoub,1 Aya Abed Altaleb,1 Khaloud Atif,1 Mohamad Rahal,2 Bassem Sadek31Department of Biomedical Sciences, College of Health Sciences, Abu Dhabi University, Abu Dhabi, United Arab Emirates; 2Department of Pharmaceutical Sciences, School of Pharmacy, Lebanese International University, Beirut, Lebanon; 3Department of Pharmacology & Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates*These authors contributed equally to this workCorrespondence: Bassem Sadek, Department of Pharmacology and Therapeutics, College of Medicine & Health Sciences, United Arab Emirates University, P.O. Box 15551, Al Ain, United Arab Emirates, Tel + 971 3 7137 512, Fax + 971 3 7672 033, Email bassem.sadek@uaeu.ac.aeIntroduction: Alzheimer’s disease (AD) involves neuroinflammation that worsens cognitive decline. Thymoquinone (TQ) has potent anti-inflammatory activity, but its therapeutic application is limited by poor solubility, stability, and systemic bioavailability, which may restrict effective brain exposure. This study developed TQ-loaded hexosomal nanoparticles (TQ-HNP) to enhance TQ delivery and therapeutic efficacy in a dizocilpine (MK-801)– induced mouse model of AD.Methods: TQ-HNP were prepared using glyceryl monooleate, oleic acid, and poloxamer 407, optimized to ~104 nm size, − 31 mV zeta potential, and ~95% entrapment efficiency. Following intraperitoneal administration of free TQ and TQ-HNP, male C57BL/6 mice treated with dizocilpine received intraperitoneal injections of free TQ or TQ-HNP and were subsequently evaluated for cognitive function (Novel Object Recognition test), anxiety-like behavior (Open Field test), and brain levels of the pro-inflammatory cytokines IL-6, TNF-α, and IL-1β.Results: Dizocilpine impaired memory and increased anxiety-like behavior in assessed mice, while TQ-HNP significantly improved both outcomes compared to free TQ. TQ-HNP also reduced IL-6 in the hippocampus and cerebellum and lowered TNF-α and IL-1β in the cerebellum, confirming its anti-inflammatory efficacy.Discussion: TQ-HNP enhanced the brain delivery of thymoquinone, mitigated neuroinflammation, and restored cognitive function in the AD-like mouse model, supporting its potential as a nanocarrier-based therapeutic strategy for Alzheimer’s disease and other neurodegenerative disorders.Keywords: thymoquinone, hexosomal nanoparticles, alzheimer’s disease, neuroinflammation, cognitive impairment, dizocilpine, nanocarrier, neuroprotection, blood–brain barrier, cytokines, C57BL/6 mice