As the pregnancy stage advances, prostaglandin (PG) concentrations increase in the uterus, being responsible for the increased uterus contractility during labor. Therefore, regulating the concentration of the PGs in the uterus is important for controlling preterm delivery. In oriental medicine traditionally, an acupuncture of LI-4 controls for the function and motility of the uterus. In this study, acupuncture treatment on the LI-4 acupoint in nonpregnant and pregnant rats was evaluated for its efficacy in the expression of COX-2 enzyme and uterus motility. Whether the rats were pregnant or not, immunohistochemical localization of the COX-2 enzyme was primarily found in the uterine endometrium with weak localization in the uterine myometrium. The level of expression in these two locations was intensified by pregnancy but reduced by the LI-4 acupuncture. The infusion of PGF_2α in pregnant rats caused and increased COX-2 expression in the myometrium while it caused a decreased expression in the endometrium. The uterus motility monitored during the LI-4 acupuncture reduced to 67.0% in nonpregnant rats, and to 75.0% in pregnant rats. PGF_2α infusion in pregnant rats increased uterine motility to 117.3%. The significant reduction in uterus motility in pregnant rats supports the role of LI-4 acupuncture in inhibiting the expression of COX-2 enzyme that can be used to regulate complicated preterm labor.

As pregnancy advances, prostaglandins (PG) increase in the uterus, leading to elevated uterine contractility. Therefore, regulating the concentration of PG in the uterus can be a key factor for controlling the duration of labor. Since the synthesis of PGs in the uterus is catalyzed by cyclooxygenase-2 (COX-2), devising a tool to regulate the expression of COX-2 could provide a method for treating complicated labor. In this study, Sp-6 acupuncture treatment was evaluated for its potential in controlling uterine motility. Immunohistochemical methods showed the COX-2 enzyme was primarily found in the endometrium and myometrium of rat uterus. COX-2 expression in these two locations were intensified by pregnancy, but reduced by acupuncture at the Sp-6 acupoint. Uterine motility monitored during Sp-6 acupuncture was reduced by 28.15% (p < 0.05) and 19.88% (p < 0.05) in pregnant rats and non-pregnant rats, respectively. The significant reduction of uterine motility in pregnant rat suggests a role for Sp-6 acupuncture in regulating the expression of COX-2 during pregnancy. These results suggest that Sp-6 acupuncture could be used as a complementary method for controlling labor in human pregnancy.