Effect of acupuncture treatment on uterine motility and cyclooxygenase-2 expression in pregnant rats.

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(2alpha) 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(2alpha) 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.