Regulation of Mild Moxibustion on Uterine Vascular and Prostaglandin Contents in Primary Dysmenorrhea Rat Model

Abstract

Objective: Primary dysmenorrhea (PD) is a common and high incidence disease in gynecology, which seriously affects the quality of life in young women. Our previous study found that mild moxibustion could treat abdominal pain of PD patients, but the mechanism is still unclear. Therefore, this study aims to partly investigate the treatment mechanism of moxibustion for PD, especially on uterine microcirculation.

Methods: Forty 3-month-old Sprague Dawley female rats were randomly divided into four groups, including group A (saline control group, n = 10), group B (control plus moxibustion group, n = 10), group C (PD model group, n = 10), group D (PD. model plus moxibustion group, n = 10). The PD rat model was established by injecting estradiol benzoate and oxytocin. Mild moxibustion on Sanyinjiao (SP6) and Guanyuan (CV4) acupoints was once a day, 20 minutes per time, for 10 consecutive days. A vaginal smear was used to test the estrous cycle of rats. Uterine microvascular thickness was observed by stereomicroscope. And we detected the content of prostaglandin F_2α (PGF_2α ) and prostaglandin E₂ (PGE₂) in uterine tissue by enzyme-linked immunosorbent assay.

Results: Mild moxibustion can enlarge the microvessels, improve the microcirculation disturbance, and relieve the swelling of the uterus in PD rats. During the mild moxibustion intervention, the contents of PGF_2α and PGE₂ in uterus issues were synchronous increases or decreases and the changes of PGE₂ were more obvious, but the changes of uterine microvasculature and morphology caused by the decrease of PGF_2α were greater than PGE₂.

Conclusion: Mild moxibustion at SP6 and CV4 acupoints may relax uterine microvascular obstacle by reducing the content of PGF_2α in uterine tissue, improve the microcirculation disorder, and then alleviate the PD rat's uterine swelling.

Figure 1

The regular vaginal smear of the typical rat estrus cycle. The cells of the different estrous cycles in rats were as follows: the small and round nucleated epithelial cells were the main cells in the prophase of estrus. In estrus, irregular squamous epithelial cells predominate. White blood cells, nucleated epithelial cells, and keratinized epithelial cells can be seen in the later stage of estrus, but the total number is small. During the estrus, most of them were white cells, and a few of them were nuclear epithelial cells and keratinized epithelial cells. (a) Propstrum. (b) Estrus. (c) Postestrus. (d) Diestrus.

Figure 2

Flowchart of experiment development. SP6 = Sanyinjiao; CV4 = Guanyuan.

Figure 3

(a, b) The location of SP6 and CV4 acupoints on the body of SD rats. SP6 is located 10 mm above the tip of the inner ankle of the hind limb, and CV4 is located about 25 mm below the umbilicus.

Figure 4

The schematic diagram of the whole experimental process of moxibustion intervention on healthy and PD rats. (A) The moxibustion on health and PD rats. (B) Microscopical observation of uterine microvasculature in rats. (C) The separation of the uterus. (D) Measurement of uterine thickness in vitro and detection PGF_2α and PGE₂ of uterus tissue by ELISA.

Figure 5

In (a), changes of uterine tube diameter during moxibustion in different body states of rats (A), thickness of uterus in vitro (mm) (B), and four groups of the typical uterus in vitro (C) are shown. In (b), changes of microvascular diameter during moxibustion in different body states of rats (A), effects of moxibustion on uterine microvascular diameter under microscope (B), and microscopic view of uterine microvascular (C) are shown. Data are expressed as the upper quartile and the lower quartile. ^∗P < 0.05, ^∗∗P < 0.01, ^∗∗∗∗P < 0.0001 versus group A. ^οοοοP < 0.0001 versus group B. ^ΔΔΔΔP < 0.0001 versus group C.

Figure 6

In (a), changes of PGF_2a during moxibustion in different body states of rats (A) and effects of moxibustion on the content of PGF_2a in uterine tissue (B) are shown. In (b), changes of PGE₂ during moxibustion in different body states of rats (A) and effects of moxibustion on the content of PGE₂ in uterine tissue (B) are shown. PGF_2a data are expressed as the mean ± SEM. ^∗P < 0.05 versus group A. PGE₂ data are expressed as the upper quartile and the lower quartile. ^∗∗∗P < 0.001, ^∗∗∗∗P < 0.0001 versus group A. ^ΔP < 0.05 versus group C.