The Analgesic Effect and Potential Mechanisms of Acupuncture for Migraine Rats: A Systematic Review and Meta-Analysis

Figures & data

Table 1 Search Strategy in PubMed

Steps	Search
#1	“Migraine disorders” [MeSH] OR “migraine” [Ti/Ab] Filters: from 2013–2022
#2	“Acupuncture” [MeSH] OR “acupuncture therapy” [Ti/Ab] OR “electroacupuncture” [Ti/Ab] OR “acupoints” [Ti/Ab] Filters: from 2013–2022
#3	“Rats” [MeSH] OR “mice” [MeSH] OR “animal study” [Ti/Ab] OR “mechanism” [Ti/Ab] OR “preclinical study” [Ti/Ab] Filters: from 2013–2022
#4	#1 AND #2 AND #3

Figure 1 Flow diagram of study selection process.

Abbreviations: CNKI, China National Knowledge Infrastructure; VIP, VIP Database for Chinese Technical Periodical; Sino Med, Chinese biomedical literature service system.

Table 2 Characteristics of the 21 Included Studies

Study (Year)	Animals (Species, Sex)	Modeling Method	Control Group (n)	Intervention Group					Outcome Measurement	Reference
				Method (n)	Stimulator Parameters	Acupoints	Acupuncture Session, Retention Time	Insertion Depth
Zhu (2017) a	SD rats, male	Dural electrical stimulation	Migraine group (8) SA group (8)	EA (8)	Alternating frequency of 2/15 Hz; 0.5–1 mA intensity	GB20, GB34	3 sessions; 10 min	2–3 mm	FMWT	[25]
Qu (2017)	SD rats, male	Dural electrical stimulation	Migraine group (6) SA group (6)	EA (6)	Alternating frequency of 2/15 Hz; 0.5–1mA intensity	GB20, GB34	3 sessions; 10 min	GB20: 8 mm; GB34: 5 mm	FMWT PMWT	[26]
Zhao (2017) a	SD rats, male	Dural electrical stimulation	Migraine group (10) SA group (10)	EA (10)	Alternating frequency of 2/15 Hz; 0.5–1 mA intensity	GB20, GB34	7 sessions; 15 min	NM	FMWT	[27]
Zhang (2020)	SD rats, male	Trigeminal ganglion electrical stimulation	Migraine group (10)	EA (10)	Alternating frequency of 2/15 Hz; 1mA intensity	GB20, SJ5	5 sessions; 20min	2–3mm	FMWT	[28]
Zhang (2015)	SD rats, male	Trigeminal ganglion electrical stimulation	Migraine group (10)	EA (10)	Alternating frequency of 2/15 Hz; 1mA intensity	GB20, SJ5	1 session; 30min	2–3mm	CGRP	[29]
Zhu (2017) b	SD rats, male	Nitroglycerin	Migraine group (8)	EA (8)	Alternating frequency of 2/15 Hz; 0.5–1 mA intensity	GB20	3 sessions; 10 min	2–3mm	FMWT PMWT	[30]
Zhang (2018)	SD rats, male	Nitroglycerin	Migraine group (5)	EA (5)	Alternating frequency of 2/15 Hz; 1mA intensity	GB20, SJ5	5 sessions; 20min	2–3mm	CGRP	[31]
Ye (2018)	SD rats, both male and female	Nitroglycerin	Migraine group (10) SA group (10)	EA (10)	Alternating frequency of 10/50 Hz; 0.5–1 mA intensity	GB20, GB34, SJ5	1 session; 30 min	GB20: 2–3mm; SJ5: 1mm; GB34: 6mm	50% PMWT	[32]
Wang (2018) a	SD rats, both male and female	Nitroglycerin	Migraine group (10) SA group (10)	EA (10)	Alternating frequency of 2/100 Hz; NM	GB20, GB34, SJ5	1 session; 30 min	3–10mm	50% PMWT	[33]
Liu (2019) a	SD rats, both male and female	Nitroglycerin	Migraine group (10)	EA (10)	Alternating frequency of 10/50 Hz; 0.5–1 mA intensity	GB20, GB34, SJ5	1 session; 30 min	1–6mm	50% PMWT	[34]
Liu (2019) b	SD rats, both male and female	Nitroglycerin	Migraine group (10)	EA (10)	Alternating frequency of 10/50 Hz; 0.5–1 mA intensity	GB20, GB34, SJ5	1 session; 30 min	1–6mm	50% PMWT	[35]
Wang (2018) b	Wistar rats,	Nitroglycerin	Migraine group (8)	MA (8)	/	GB20, DU20, PC6, LR3	8 sessions; 30min	1–2mm	CGRP	[36]
Huang (2021)	Wistar rats,	Nitroglycerin	Migraine group (8)	MA (8)	/	GB20, DU20, PC6, LR3	8 sessions; 30min	1–2mm	CGRP	[37]
Zhang (2022)	SD rats, both male and female	Nitroglycerin	Migraine group (10)	EA (10)	Alternating frequency of 10/50 Hz; 0.5–1 mA intensity	GB20, GB34, SJ5	8 sessions; 30 min	1–6mm	50% PMWT	[38]
Zhang (2016)	SD rats, male	Trigeminal ganglion electrical stimulation	Migraine group (8)	EA (8)	Alternating frequency of 2/15 Hz; 1mA intensity	GB20, SJ5	5 sessions; 30min	2–3mm	CGRP	[39]
Pei (2017)	SD rats, male	Dural electrical stimulation	Migraine group (16) SA group (16)	EA (16)	Alternating frequency of 2/15 Hz; 0.5–1 mA intensity	GB20	7 sessions; 15 min	2–3mm	FMWT PMWT	[40]
Liu (2021)	SD rats, male	Inflammatory soup	Migraine group (10) SA group (10)	EA (10)	Alternating frequency of 2/15 Hz; 1 mA intensity	GB20, GB34	4 sessions; 15 min	1.5 mm	50% FMWT 50% PMWT	[41]
Qu (2020) a	SD rats, male	Inflammatory soup	Migraine group (7) SA group (7)	EA (7)	Alternating frequency of 2/15 Hz; 0.5–1 mA intensity	GB8	1 session; 15 min	8mm	50% FMWT	[42]
Qu (2020) b	SD rats, male	Inflammatory soup	Migraine group (8) SA group (8)	EA (8)	Alternating frequency of 2/15 Hz; 0.5–1 mA intensity	GB20	3 sessions; 15 min	8mm	50% FMWT	[43]
Zhao (2020)	SD rats, male	Dural electrical stimulation	Migraine group (10) SA group (10)	EA (10)	Alternating frequency of 2/15 Hz; 0.5–1 mA intensity	GB20, GB34	5 sessions; 15 min	2–3mm	FMWT PMWT	[44]
Zhao (2017) b	SD rats, male	Dural electrical stimulation	Migraine group (10) SA group (10)	EA (10)	Alternating frequency of 2/15 Hz; 0.5–1 mA intensity	GB20	7 sessions; 15 min	2–3mm	FMWT PMWT	[49]

Notes: The first column uses the combination of the author’s last name and the year of publication of the article as the pronoun for the article, and the suffix a or b is used to distinguish it if the name is repeated; In addition, what is not mentioned in the article is unknown in the table with/denotation.

Abbreviations: SD, Sprague Dawley; SA, sham acupuncture; EA, electroacupuncture; MA, manual acupuncture; FMWT, facial mechanical withdrawal threshold; PMWT, paw mechanical withdrawal threshold; 50% FMWT, 50% facial mechanical withdrawal threshold; 50% PMWT, 50% paw mechanical withdrawal threshold; NM, not mentioned; GB20, Fengchi; GB34, Yanglignquan; GB8, Shuaigu; SJ5, Waiguan.

Figure 2 Characteristics of the 21 included studies.

Notes: (A) Schematic diagram of the proportion of different animal models in the included article. (B) Number of different acupoints selected for the treatment of migraine model animals in the included articles. (C) The proportion of combinations of different acupoints in the included articles. (D) Statistics on the number of times different outcomes were used in the included articles. (E) The duration of treatment compared between included articles. (F) The duration of a single treatment compared between included articles.

Abbreviations: FMWT, facial mechanical withdrawal threshold; PMWT, paw mechanical withdrawal threshold; 50% FMWT, 50% facial mechanical withdrawal threshold; 50% PMWT, 50% paw mechanical withdrawal threshold; GB8, Shuaigu; LR3, Taichong; PC6, Neiguan; DU20, Baihui; SJ5, Waiguan; GB34, Yanglignquan; GB20, Fengchi.

Table 3 Risk of Bias Assessment According to the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) Tool

Study	1	2	3	4	5	6	7	8	9	10	Scores	Reference
Zhu (2017) a	H	L	?	L	NA	?	?	L	L	L	5	[25]
Qu (2017)	L	L	?	L	NA	?	?	L	L	L	6	[26]
Zhao (2017) a	H	L	?	L	NA	?	?	?	L	L	4	[27]
Zhang (2020)	H	L	?	L	NA	?	?	?	L	L	5	[28]
Zhang (2015)	H	L	?	L	NA	?	?	?	L	L	5	[29]
Zhu (2017) b	L	L	?	L	NA	?	?	?	L	L	5	[30]
Zhang (2018)	L	L	?	L	NA	?	L	?	L	L	6	[31]
Ye (2018)	L	L	?	L	NA	?	?	L	L	L	6	[32]
Wang (2018) a	L	L	?	L	NA	?	?	L	L	L	6	[33]
Liu (2019) a	L	L	?	L	NA	?	?	L	L	L	6	[34]
Liu (2019) b	L	L	?	L	NA	?	?	L	L	L	6	[35]
Wang (2018) b	L	L	?	L	NA	?	L	?	L	L	6	[36]
Huang (2021)	L	L	?	L	NA	?	L	?	L	L	6	[37]
Zhang (2022)	L	L	?	L	NA	?	?	L	L	L	6	[38]
Zhang (2016)	L	L	?	L	NA	?	L	L	L	L	7	[39]
Pei (2017)	L	L	?	L	NA	?	L	L	L	L	7	[40]
Liu (2021)	H	L	?	L	NA	?	L	L	L	L	6	[41]
Qu (2020) a	L	L	?	L	NA	?	L	L	L	L	7	[42]
Qu (2020) b	L	L	?	L	NA	?	L	L	L	L	7	[43]
Zhao (2020)	H	L	?	L	NA	?	?	L	L	L	5	[44]
Zhao (2017) b	H	L	?	L	NA	?	L	L	L	L	6	[49]

Notes: (1) Generation of animal allocation sequence was random; (2) each group was similar or was at adjusted at baseline; (3) the allocation was adequately concealed; (4) animals were housed at random; (5) both animal breeders and researchers were blinded for the intervention of each animal received; (6) animals were selected randomly for outcome evaluation; (7) outcome evaluator was blinded; (8) the incomplete outcome data were absolutely addressed; (9) reports of the research were free of selective outcome reporting; (10) study was evidently free of other potential issues which may cause bias.

Abbreviations: L, low-risk bias; H, high risk bias; ?, unclear; NA, not applicable.

Table 4 Quality Assessment of Included Studies

Study	1	2	3	4	5	6	7	8	9	10	Scores	Reference
Zhu (2017) a	Y	Y	Y	N	N	Y	Y	N	Y	N	6	[25]
Qu (2017)	Y	Y	Y	N	N	N	Y	N	N	N	4	[26]
Zhao (2017)	Y	Y	Y	N	N	N	Y	N	N	N	4	[27]
Zhang (2020)	Y	Y	Y	N	Y	N	Y	N	Y	N	5	[28]
Zhang (2015)	Y	N	Y	N	Y	N	Y	N	Y	N	5	[29]
Zhu (2017) b	Y	N	Y	N	N	N	Y	N	N	N	3	[30]
Zhang (2018)	Y	Y	Y	N	Y	N	Y	N	Y	N	6	[31]
Ye (2018)	Y	Y	Y	N	N	N	Y	N	Y	N	5	[32]
Wang (2018)	Y	Y	Y	N	N	N	Y	N	N	N	4	[33]
Liu (2019) a	Y	Y	Y	N	N	N	Y	N	Y	N	5	[34]
Liu (2019) b	Y	Y	Y	N	N	N	Y	N	Y	N	5	[35]
Wang (2018) b	Y	Y	Y	N	Y	N	Y	N	Y	N	6	[36]
Huang (2021)	Y	Y	Y	N	Y	N	Y	N	N	N	5	[37]
Zhang (2022)	Y	Y	Y	N	N	N	Y	N	N	N	4	[38]
Zhang (2016)	Y	Y	Y	N	Y	N	Y	Y	Y	Y	8	[39]
Pei (2017)	Y	Y	Y	N	Y	N	Y	N	Y	Y	7	[40]
Liu (2021)	Y	Y	Y	N	Y	Y	Y	Y	Y	N	8	[41]
Qu (2020) a	Y	Y	Y	Y	Y	Y	Y	N	Y	Y	9	[42]
Qu (2020) b	Y	Y	Y	Y	Y	Y	Y	N	Y	Y	9	[43]
Zhao (2020)	Y	Y	Y	N	N	N	Y	N	Y	Y	6	[44]
Zhao (2017)	Y	Y	Y	N	Y	N	Y	Y	Y	Y	8	[49]

Notes: Studies fulfilling the criteria of the following: (1) peer-reviewed journal; (2) temperature control; (3) animals were randomly allocated; (4) blind established model; (5) blinded outcome assessment; (6) reporting of animals excluded from analysis; (7) appropriate animal model; (8) calculation of sample size; (9) statement of compliance with animal welfare regulations; (10) possible conflicts of interest.

Abbreviations: Y, yes; N, no.

Figure 3 Results of meta-analysis.

Notes: Pool results of acupuncture-treated migraine model rats versus migraine model rats on (A) FMWT, (B) PMWT, (C) 50% FMWT, (D) 50% PMWT and (E) CGRP; and the results of migraine model rats treated with sham-acupuncture on (F) FMWT, (G) PMWT, (H) 50% FMWT and (I) 50% PMWT.

Abbreviations: WMD, weighted mean difference; SMD, standard mean difference.

Table 5 Potential Mechanism of Included Studies

Study	Potential Mechanism	Reference
Zhu (2017) a	Up-regulated 5-HT1B receptor mRNA and protein in TNC and TG tissue of migraine rats	[25]
Qu (2017)	Up-regulated 5-HT1F receptor mRNA and protein in TNC, TG and RMg tissue of migraine rats	[26]
Zhao (2017) a	Up-regulated 5-HT1D receptor mRNA and protein in TNC and TG tissue of migraine rats	[27]
Zhang (2020)	Inhibited miR-34a-5p expression in TG, increase SIRT1 expression, down-regulated IL-1β/ COX-2, reduce PGE2 synthesis, reduce CGRP released from peripheral terminals of migraine rats	[28]
Zhang (2015)	Up-regulated CB1 in TG tissue, down-regulated CGRP serum levels of migraine rats	[29]
Zhu (2017) b	NM	[30]
Zhang (2018)	Inhibited trigeminal nerve-vascular activation by the kynurate pathway, reduced serum CGRP levels of migraine rats	[31]
Ye (2018)	Down-regulated NO and ET-1 levels in serum	[32]
Wang (2018)	Up-regulated 5-HT in serum, down-regulated CGRP and SP in serum	[33]
Liu (2019) a	Down-regulated NO, ET and CGRP levels in serum	[34]
Liu (2019) b	Down-regulated CGRP and SP in serum	[35]
Wang (2018) b	Inhibited serum inflammatory factors (CGRP, IL-1β, SP TNF-α)	[36]
Huang (2021)	Down-regulated 5-HT, CGRP, SP and ADORA1 in migraine rats	[37]
Zhang (2022)	Down-regulated IL-6, TNF-α positive cells in brainstem and CGRP mRNA expression in STN	[38]
Zhang (2016)	Up-regulated CB1 receptor expression and inhibited TGES-induced changes in IL-1β, COX2, PGE2 and CGRP.	[39]
Pei (2017)	Down-regulated 5-HT7R positive cells and protein expression in the PAG, RMg and TNC	[40]
Liu (2021)	Down-regulated 5-HT7R positive cells, mRNA expression and protein expression by regulating PKA and ERK 1/2 in TG and TNC	[41]
Qu (2020) a	Reduced C-fiber evoked WDR neuronal discharges of the TCC and exerted a DNIC effect	[42]
Qu (2020) b	Decreased the discharge rate of neurons in the TCC and regulated the activity state of TCC neurons	[43]
Zhao (2020)	Inhibited dural mast cells, macrophages, and serum inflammatory factors (CGRP, IL-1β, IL-6, TNF-α, BDNF and COX-2 in plasma levels)	[44]
Zhao (2017)	Inhibited CGRP protein expression in the TG, TNC and VMTN. Inhibited CGRP positive cells in the TG.	[49]

Abbreviations: TG, trigeminal ganglia; TNC, trigeminal nucleus caudalis; NM, not mentioned; NO, nitric oxide; CB1, cannabinoid receptor 1; PEG2, serum prostaglandin E2; ET-1, endothelin-1; CGRP, calcitonin gene-related peptide; SP, substance P; 5-HT, 5-hydroxytryptamine; ET, endothelin; IL-6, interleukin 6; TNF-α, tumor necrosis factor-alpha; PAG, periaqueductal grey; RMg, raphe magnus nucleus; PKA, phosphorylation of protein kinase A; ERK 1/2, extracellular signal-regulated kinase 1/2; WDR, wide dynamic range; TCC, trigeminocervical complex; DNIC, diffuse noxious inhibitory controls; IL-1β, interleukin 1β; STN, spinal trigeminal nucleus; BDNF, brain derived neurotrophic factor; COX2, cyclooxygenase-2; VMTN, ventroposterior medial thalamic nucleus; ADORA1, Adenosine A1 Receptor.

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