Moxibustion pretreatment refers to moxibustion treatment in advance during the period of no disease or disease omen, which belongs to a type of acupuncture and moxibustion pretreatment and has the function of disease prevention. Currently, research on acupuncture and moxibustion pretreatment has involved various diseases. A study has found that electroacupuncture pretreatment can effectively induce cerebral ischemic tolerance [13]. Li et al. revealed that acupuncture and moxibustion pretreatment can inhibit injection of amyloid-beta protein Induced neuronal damage and degeneration in hippocampus of rats [14]. Kim et al. showed that acupuncture pretreatment can reduce the content of inflammatory factor interleukin-1β (IL-1β), thereby alleviating epileptic seizures behavior in mice [15]. Another study has shown that acupuncture pretreatment can increase the expression of glutamate decarboxylase (GAD)-67 in hippocampus and inhibit KA induced seizures and hippocampal cell death [16]. However, there is limited research on the treatment of epilepsy with moxibustion pretreatment both domestically and internationally, and further research is needed.
A study has shown that electroacupuncture stimulation of Dazhui (GV 14) and Baihui (Du 20) acupoints in epileptic rats can inhibit the inflammatory response mediated by microglia and have a protective effect on hippocampal neurons [17]. Acupuncture at point GV 14 can significantly reduce the mortality rate of rats during seizures [18]. Acupuncture at the ST36 and GV14 acupoints may have a protective effect on brain cells during epileptic seizures by affecting the expression of interleukin-8 (IL-8) and interleukin-10 (IL-10) in epileptic rats [19]. The effective mechanism of moxibustion at ST36 acupoint in treating epileptic rats may be related to reducing interleukin-2 (IL-2) in serum [20]. Based on the above analysis, this study selected at ST36 and GV14 acupoints for moxibustion pretreatment.
P2X7R belongs to the ATP-sensitive ion channel type purinergic receptor. P2X7Rs are expressed throughout the central nervous system, including brain areas implicated in epilepsy development, such as the frontal cortex, hippocampus and amygdala, where they have been reported to be functional on all cell types [21]. Over the past few decades, a substantial body of evidence has been accumulated demonstrating a role for P2X7R during seizure generation and epilepsy [22]. Research has shown that intracerebral injection of ATP or BZ-ATP, an agonist at the P2X7R, into the mouse brain transiently enhanced electrographic seizures during status epilepticus. In contrast, Central injection of two chemically distinct P2X7R antagonists, brilliant blue G(BBG) and A-438079, reduced seizures during status epilepticus [23]. These results are consistent with the results of this study. The physiological role of P2X7R in epilepsy includes driving inflammatory processes, involvement in neuronal excitability, and astrocyte function [24, 25], however the specific mechanism remains to be further elucidated.
In recent years, research has shown that inflammatory response is closely related to epilepsy. Impaired regulation of the activation and resolution of inflammatory cells and molecules in the injured neuronal tissue is a critical factor to the development of epilepsy [26]. Transforming growth factor-β pathway inhibition prevents the activation of astrocytes during epileptogenesis, leading to a reduction in spontaneous seizure activity and brain inflammation [27]. Inflammation in the brain can increase the permeability of the blood-brain barrier and promote the transmission of glutamate neurotransmitters [28]. Glutamic acid and γ- Imbalance of aminobutyric acid can induce epilepsy [29], while glutamate receptors are mainly expressed in the hippocampal CA1 region [30]. In previous studies, it has been proved that acupuncture and moxibustion intervention can reduce the death of neurons in KA-induced epilepsy mice. This possible mechanism is that the neuroprotective effect of hippocampal neurons is that the γ-aminobutyric acid-mediated signal pathway increases Glutamic acid decarboxylase (GAD) [16]. A study has found that electroacupuncture at ST36 possess some curative effect on epileptic rats, related with change of GAD-67 mRNA level in dentate gyrus region [31]. In addition, the study indicates that moxibustion therapy mainly targets the effects of ST36 on epilepsy, and the possible mechanism of occurrence is to improve clinical symptoms by decreasing serum Tumor Necrosis Factor-α (TNF-α) and interleukin-6 (IL-6) levels [8]. These studies show that acupuncture and moxibustion can reduce the brain damage caused by KA-induced seizures.
According to our experimental results, moxibustion pretreatment at ST36 and GV14 acupoints in mice for 14 and 21 days can significantly improve the seizure stage, reduce seizure stage and decrease duration of SE in KA model mice. However, moxibustion pretreatment for 7 days did not yield the same results. So, it is probably means that moxibustion pretratment can help to protect the damage from epileptic seizures but need to accumulative effect.
In the experiment of using a P2X7R agonist (BzATP) or antagonist (A438079) to intervene in epileptic seizures in mice, it was found that BzATP aggravated seizure stage, increased highest seizure stage and prolonged duration of SE while using A438079 showed opposite results. Preconditioning the same acupoints with moxibustion for 14 days can reduce the level of seizures in mice using BzATP, decreased seizure stage, alleviated highest seizure stage, and reduced the duration of SE. From this result we can make a hypothesis, moxibustion pretreatment attenuate epileptic seizures may via P2X7R to mediate inflammatory response.