Selective phosphodiesterase-2A inhibitor alleviates radicular inflammation and mechanical allodynia in non-compressive lumbar disc herniation rats.

PURPOSE: Phosphodiesterase inhibitors possess anti-inflammatory properties. In addition, some studies report that phosphodiesterase 2A (PDE2A) are highly expressed in the dorsal horn of the spinal cord. The present study aimed to investigate whether intrathecal administration of Bay 60-7550, a specific PDE2A inhibitor, could alleviate mechanical allodynia in non-compressive lumbar disc herniation (NCLDH) rats. METHODS: Rat NCLDH models by autologous nucleus pulposus implantation to dorsal root ganglion were established. Vehicle or Bay 60-7550 (0.1, 1.0 mg/kg) was injected by intrathecal catheter at day 1 post-operation. The ipsilateral mechanical withdrawal thresholds were analyzed from the day before surgery to day 7 after surgery. At day 7 post-operation, the ipsilateral lumbar (L4-L6) segments of the spinal dorsal horns were removed, and tumor necrosis factor α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), cyclic adenosine monophosphate (cAMP), and cyclic guanosine monophosphate (cGMP) expressions were measured by ELISA. Furthermore, PDE2A mRNA and protein expressions in spinal cord were measured by Real-Time PCR and Western blot. RESULTS: Intrathecal administration of the PDE2A inhibitor Bay 60-7550, significantly attenuated mechanical allodynia, down-regulated spinal TNF-α, IL-1ß and IL-6 over-expressions, increased the expression of spinal cAMP, as well as cGMP in a more remarkable manner, and decreased the spinal PDE2A expression in NCLDH rats in a dose-dependent manner. CONCLUSIONS: Bay 60-7550 alleviated mechanical allodynia and inflammation in NCLDH rats, which might be associated with increased cAMP and especially cGMP increase. Thus, spinal PDE2A inhibition might represent a potential analgesic strategy for radiculopathy treatment in non-compressive lumbar disc herniation.

[Method and current situations on acupuncture clinical trial registration in the world].

Acupuncture clinical trial registration can help improving the quality, internationalization and influence of acupuncture clinical trials. Results retrieved from the related databases show that the number of acupuncture clinical trials registration is increasing year by year, especially that from mainland China. The registered clinical trials mainly involve researches on pain management, functional disorders of an organ or system, etc. But most of the acupuncture clinical trials conducted in mainland China have not been registered and the trials quality needs being improved. The registration method is introduced in this paper.