关键词: 穴位埋线, 羊肠线, 聚乙丙交酯线, 足三里, 时效性刺激效应, 穴位启动机制

Abstract: BACKGROUND: The researchers noted that upon embedding clinical-grade catgut and polyglycolide-co-lactide threads in the normal human “Zusanli” (ST 36) acupoint, the local area displayed temporal and inflammatory stimulatory effects, resulting in thread differentiation. However, the underlying mechanism behind thread involvement remains to be studied.
OBJECTIVE: To investigate the expression levels of calcitonin gene-related peptide, 5-hydroxytryptamine, leukotriene B4, and bradykinin at point “Zusanli” (ST 36) in rats after embedding catgut and polyglycolide-co-lactide respectively at different time points. 
METHODS: 110 male SD rats were divided into a blank group (10 rats), a catgut embedding group (50 rats), and a polyglycolide-co-lactide embedding group (50 rats) according to the random number table method. In the blank group, no thread was embedded. In catgut embedding group and the polyglycolide-co-lactide embedding group, the thread was embedded in the left side of the ST36 acupoint once. Tissue was collected from the left side of the ST36 acupoint area 8 hours, 3, 7, 14, and 21 days after embedding. The expression levels of calcitonin gene-related peptide and 5-hydroxytryptamine were detected by immunohistochemistry, and the contents of leukotriene B4 and bradykinin were detected by ELISA. 
RESULTS AND CONCLUSION: (1) Compared with the blank group, the expression of calcitonin gene-related peptide, 5-hydroxytryptamine, bradykinin, and leukotriene B4 was significantly increased in the 8 hours, 3, 7, 14, and 21 days of the catgut embedding group (P < 0.05); calcitonin gene-related peptide expression was significantly increased in 8 hours, 3, 7, and 14 days in the polyglycolide-co-lactide embedding group (P < 0.05); the expression of bradykinin was significantly increased in 8 hours, 3, and 7 days (P < 0.05); the expression of leukotriene B4 was significantly increased at 8 hours, 3, 7, 14, and 21 days (P < 0.05). (2) Compared with the polyglycolide-co-lactide embedding group, the expression of calcitonin gene-related peptide was increased at 7, 14, 21 days after thread embedding (P < 0.05), and the expression of 5-hydroxytryptamine was increased at 8 hours, 3, 7, 14 and 21 days after thread embedding (P < 0.05); contents of leukotriene B4 and bradykinin in tissues were increased at 8 hours, 3, 14 and 21 days after embedding (P < 0.05) in the catgut embedding group. (3) The results show that calcitonin gene-related peptide, 5-hydroxytryptamine, leukotriene B4, and bradykinin in the acupoint region alter after catgut embedding in the ST36 of rats, as well as the alteration of calcitonin gene-related peptide, leukotriene B4, and bradykinin is found in the acupoint region after polyglycolide-co-lactide embedding in rats, which may be one of the mechanisms involved in the local time sensitive stimulus effects caused by embedding threads at acupoints. Moreover, there is a discernible difference between the two thread types.

Key words: acupoint embedding, catgut thread, polyglycolide-co-lactide thread, Zusanli, time-sensitive stimulation effect, acupoint initiation mechanism