Objective

2

To observe the effect of "Zhibian" (BL54)-toward-"Shuidao" (ST28) needling technique on the relative protein expression of the signaling pathway of nucleotide-binding oligomerization domain-containing protein 1 (NOD1)/ receptor-interacting protein 2 (RIP2)/nuclear factor kappa-B (NF-κB) and the expression of proinflammatory cytokines in the rats with primary dysmenorrhea (PD)

so as to explore the underlying mechanism of this acupuncture technique for pain alleviation in PD.

Methods

2

Thirty female SD rats of SPF grade with normal estrous cycle were randomized into a blank group

a model group and an acupuncture group

10 rats in each one. Using the intraperitoneal injection with estradiol benzoate combined with oxytocin

PD model was prepared in the model group and the acupuncture group. In the acupuncture group

during model preparation

the intervention with "Zhibian" (BL54)-toward-"Shuidao" (ST28) needling technique was delivered simultaneously

20 min each time

once daily for consecutive 10 days. On day 11

within 30 min after the intraperitoneal injection with oxytocin

the writhing reaction (latency

frequency and score) was recorded; the morphology of uterine tissue was observed with HE staining

the contents of prostaglandin E

2

(PGE

2

)

prostaglandin F

2α

(PGF

2α

)

interleukin (IL)-1β

IL-18

cyclooxygenase-2 (COX-2)

and tumor necrosis factor-α(TNF-α) in the serum were detected using ELISA method; the relative protein expression of NOD1

RIP2

NF-κB p65

phosphorylation-NF-κB p65 (p-NF-κB p65) was detected in the uterine tissue using Western blot method; and the mRNA expression of NOD1

RIP2 and NF-κB p65 was detected with the quantitative real-time PCR employed.

Results

2

Compared with the blank group

in the model group

the writhing latency was prolonged (

P

<

0.01)

the writhing frequency and score increased (

P

<

0.01) in the rats; the endometrial epithelial cells showed massive degeneration and ne

crosis

with severe endometrial edema and widespread shedding

combined with neutrophil infiltration; the serum PGE

2

content was dropped (

P

<

0.01)

while those of PGF

2α

IL-1β

IL-18

COX-2

and TNF-α elevated (

P

<

0.01); the protein expression of NOD1

RIP2

NF-κB p65 and p-NF-κB p65

and the mRNA expression of NOD1

RIP2 and NF-κB p65 in uterine tissue increased (

P

<

0.01). In comparison with the model group

in the acupuncture group

the writhing latency was prolonged (

P

<

0.01)

the writhing frequency and score were reduced (

P

<

0.01) in the rats; there was less degeneration and necrosis of endometrial epithelial cells

with mild endometrial edema and very little neutrophil infiltration; the serum PGE

2

content increased (

P

<

0.01)

while those of PGF

2α

IL-1β

IL-18

COX-2

and TNF-α decreased (

P

<

0.01); the protein expression of NOD1

RIP2

NF-κB p65 and p-NF-κB p65 and the mRNA expression of NOD1

RIP2 and NF-κB p65 in uterine tissue were dropped (

P

<

0.05

P

<

0.01).

Conclusion

2

"Zhibian" (BL54)-toward-"Shuidao" (ST28) needling technique can alleviate the pain symptom of PD rats

and its action mechanism may be related to inhibiting the active expression of NOD1/RIP2/NF-κB signaling pathway in the uterine tissue

thereby reducing the inflammatory response.