In the clinic, migraine is a debilitating and common neurological condition and a primary central nervous system dysfunction that are commonly observed. An extensive study indicated that the onset of migraine is related to the activation of trigeminal neurovascular system [1]. Antidromic stimulation of trigeminal fibers induces plasma protein extravasation, mast cell activation and degranulation, vacuolation, and an increase in endothelial vesicle count in post-capillary venules of rat dura mater [2]. Inflammatory activation and peripheral sensitization of the primary sensory neurons innervating the meninges and related blood vessels are considered the basis of migraine [3,4]. Neurogenic inflammation has been proposed as a potential pathogenetic mechanism for both migraine and cluster headache [5].

Cytokines are crucial inflammatory mediators and play a significant role in inflammatory hyperalgesia [6]. Specifically, interleukin-1β (IL-1β) is an inflammatory cytokine involved in both the initiation and maintenance of inflammation, as well as neuropathic pain [[7], [8], [9]]. A previous study demonstrated an increase in IL-1β expression in the dura and cerebrospinal fluid of rats with nitroglycerin (NTG)-induced migraine [10]. Furthermore, a clinical trial revealed a significant increase in plasma IL-1β expression during migraine attacks [11]. Additionally, repeated administration of NTG induced both acute and chronic mechanical hyperalgesia, accompanied by an increase in IL-1β expression [12].

IL-1β exists as an inactive precursor and requires proteolysis by a protease to be converted into its active, mature form. This activation process involves the assembly of the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome and the activation of caspase-1 [13]. The NLRP3 inflammasome is a complex of innate immune proteins that mediates the activation of caspase-1, which then cleaves the inactive form of IL-1β (pro-IL-1β) into its active, mature form [14]. This process is crucial for the regulation of neuroinflammation mediated by microglia [12]. NLRP3 can recognize a diverse range of endogenous ligands, including bacterial infections (such as Listeria and Staphylococcus aureus), as well as muramyl dipeptide, adenosine triphosphate, nigericin, viral DNA, imidazoquinoline, asbestos, uric acid crystals, silicate, and β-amylase [12]. Upon recognition, NLRP3 assembles into an inflammasome, participating in the inflammatory response and immune regulation. The activation mechanism of NLRP3 may involve lysosomal rupture, mitochondrial DNA release, and the formation of reactive oxygen species (ROS). Studies have shown that intracranial pain caused by inflammatory stimulation of the rat dura mater promotes the assembly of NLRP3 inflammasomes in the rat trigeminal ganglion, the activation of caspase-1 and the processing and maturation of IL-1β, which may be involved in migraine-related classes [15]. Furthermore, the NLRP3 inflammasome has been implicated in several inflammatory disorders of the central nervous system, including depression [16], spontaneous intracerebral haemorrhage [17] and multiple sclerosis [18]. These findings suggest that IL-1β and NLRP3 may play a significant role in the progression of migraine.

Botulinum toxin type A (BTX-A) has been used in the prevention and treatment of chronic migraine [19]. However, the underlying mechanism of its effectiveness, particularly its relationship to the IL-1β and NLRP3 inflammasome cascade pathway, remains unclear. Therefore, we hypothesized that BTX-A could inhibit inflammation in the primary nociceptive neurons of the trigeminal nerve by suppressing the synthesis of NLRP3 inflammasome and IL-1β. To test this hypothesis, we established a rat migraine model through inflammatory stimulation of the dura mater. We then detected the expression of NLRP3 inflammasome and IL-1β in the trigeminal ganglion of the rats and explored the effects of BTX-A on these molecules. The results of this study may provide new therapeutic targets for the prevention of migraine.