[Effect of moxibustion on M2 and P2X3 receptors of bladder tissue in rats with neurogenic bladder of detrusor areflexia after lumbar-sacral spinal cord injury].

OBJECTIVE

To observe the effect of moxibustion at "Guanyuan" (CV 4) and "Shenque" (CV 8) on acetylcholine (Ach), adenosine triphosphate (ATP) and muscarinic-type choline receptor (M2) and purine receptor P2X3 in bladder tissue in the rats with neurogenic bladder (NB) of detrusor areflexia after lumbar-sacral spinal cord injury and explore the underlying mechanism of moxibustion for promoting detrusor contraction.

METHODS

Sixty SD rats were randomly divided into a model preparation group (=45) and a sham-operation group (=15). In the model preparation group, the modified Hassan Shaker spinal cord transection method was used to prepare the model of NB. In the sham-operation group, the spinal cord transection was not exerted except laminectomy and spinal cord exposure. Among the rats with successfully modeled, 30 rats were selected and divided randomly into a model group and a moxibustion group, with 15 rats in each one. On the 15th day after the operation, moxibustion was applied at "Guanyuan" (CV 4) and "Shenque" (CV 8) in the moxibustion group, 10 min at each acupoint, once a day. The consecutive 7-day treatment was as one course and the intervention for 2 courses was required. Urodynamic test was adopted to evaluate bladder function in rats. Using HE staining, the morphological changes in bladder tissue were observed. The content of Ach and ATP in bladder tissue was measured with biochemical method, and the protein and mRNA expression levels of M2 and P2X3 receptors in bladder tissue were detected with Western blot and real-time fluorescence quantification PCR method.

RESULTS

Compared with the sham-operation group, the maximum bladder capacity, leakage point pressure and bladder compliance were increased in the rats of the model group (<0.05). Compared with the model group, the maximum bladder capacity, the leakage point pressure and bladder compliance were decreased in the rats of the moxibustion group (<0.05). In the model group, the detrusor fibres were arranged irregularly, bladder epithelial tissues were not tightly connected and cell arrangement was disordered, combined with a large number of vacuolar cells. In the moxibustion group, compared with the model group, the detrusor fibres were arranged regularly, bladder epithelial cells were well distributed and vacuolar cells were reduced. Compared with the sham-operation group, the content of Ach and ATP in bladder tissue was decreased (<0.05), the protein and mRNA expression levels of M2 and P2X3 receptors were reduced (<0.05) in the model group. In the moxibustion group, the content of Ach and ATP in bladder tissue was increased (<0.05) and the protein and mRNA expression levels of M2 and P2X3 receptors were increased (<0.05) as compared with the model group.

CONCLUSION

Moxibustion at "Guanyuan" (CV 4) and "Shenque" (CV 8) may effectively improve bladder function in the rats with NB of detrusor areflexia after lumbar-sacral spinal cord injury and its underlying mechanism is related to promoting the release of Ach and up-regulating the expression of M2 receptor, thereby enhancing the release of ATP and increasing the expression of P2X3 receptor. Eventually, detrusor contraction is improved.