Therapeutic relevance of an EU-GMP certified Cannabis sativa L. strain in a dual in vivo model of cognitive impairment and chronic neuropathic pain

Ivona Costachescu¹Gogu Maria-Raluca¹Gabriela Dumitrita Stanciu^1*Carmen Solcan²Loredana Horodnicu²Andrei Szilagyi¹Vlad Constantin Craciun³Daniela-Carmen Ababei⁴Bogdan Ionel Tamba¹

• ¹Advanced Research and Development Center for Experimental Medicine, Grigore T. Popa University of Medicine and Pharmacy, Iasi, Romania
• ²Universitatea de Stiintele Vietii Ion Ionescu de la Brad din Iasi, Iași, Romania
• ³Universitatea Alexandru Ioan Cuza din Iasi, Iași, Romania
• ⁴Universitatea de Medicina si Farmacie Grigore T Popa lasi, Iași, Romania

Background: Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and frequently co-occurs with chronic pain. Worldwide, over 55 million people are affected by AD, with nearly half experiencing persistent pain. Chronic pain has been linked to accelerated memory deterioration and an increased risk of dementia, but the interplay between these conditions remains poorly understood. Existing therapies for AD and chronic pain are limited in efficacy, highlighting the need for interventions targeting multiple pathological pathways. The endocannabinoid system, which is altered in both AD and chronic pain, represents a potential therapeutic target, though its role in AD patients with comorbid pain remains unexplored. Methods: The study evaluated the effects of an EU-GMP certified Cannabis sativa L. strain (5 mg/kg, Cannabixir® Medium Flos) on neurobiological alterations in a rat model designed to explore mechanistic interactions between scopolamine-induced transient cognitive impairment and chronic neuropathic pain induced by unilateral sciatic nerve ligation. Treatment outcomes were assessed through nociceptive tests, clinical monitoring and tissue analyses to examine cognitive and pain-related effects. Results: Cannabixir® Medium Flos induced robust, time-dependent analgesia in thermal nociceptive tests, with the combination of the Cannabis sativa L. strain, donepezil and tramadol producing significantly longer response latencies than tramadol alone. Mechanical sensitivity was minimally affected across treatments. Immunohistochemical analyses revealed that Cannabixir® Medium Flos, either alone or in combination with donepezil or tramadol, produced the most pronounced neuroprotective effects, reducing astrocytic (GFAP) and microglial (Iba1) activation, lowering Caspase-3 and IL-6 expression, and preserving both hippocampal neuronal integrity as well as peripheral nerve structure. Conclusions: These findings indicate that Cannabixir® Medium Flos, particularly when combined with donepezil and tramadol, provides superior analgesic and neuroprotective effects compared to tramadol alone. Its multi-target action - alleviating thermal nociception, reducing neuroinflammation, limiting apoptosis and preserving neuronal and peripheral nerve integrity—supports its potential as an adjunct therapy in managing dementia with comorbid chronic neuropathic pain. Future studies should explore the molecular mechanisms underlying these effects and assess long-term safety and efficacy across diverse models of neurodegeneration and chronic pain.