Proteomics Analysis of the Spinal Dorsal Horn in Diabetic Painful Neuropathy Rats With Electroacupuncture Treatment

BackgroundClinical evidence demonstrates that electro-acupuncture (EA) of the Zu sanli (ST36) and Shen shu (BL23) acupoints is effective in relieving diabetic painful neuropathy (DPN); however, the underlying molecular mechanism requires further investigation, including the protein molecules associated with EA’s effects on DPN.MethodsSprague-Dawley adult male rats (n =36) were randomly assigned into control, DPN, and EA groups (n=12 each). After four weeks of EA treatment, response to mechanical pain and fasting blood glucose were analyzed. A tandem mass tag (TMT) labeling approach coupled with liquid chromatography with tandem mass spectrometry was used to identify potential biomarkers in the spinal dorsal horn. Further, proteomics analysis was used to quantify differentially expressed proteins (DEPs), and gene ontology, KEGG pathways, cluster, and string protein network interaction analyses conducted to explore the main protein targets of EA.ResultsCompared with the DPN model group, the mechanical pain threshold was significantly increased, while the fasting blood glucose levels were clearly decreased in EA group rats. Proteomics analysis was used to quantify 5393 proteins, and DEPs were chosen for further analyses, based on a threshold of 1.2-fold difference in expression level (P < 0.05) compared with control groups. Relative to the control group, 169 down-regulated and 474 up-regulated proteins were identified in the DPN group, while 107 and 328 proteins were up- and down-regulated in the EA treatment group compared with the DPN group. Bioinformatics analysis suggested that levels of proteins involved in oxidative stress injury regulation were dramatically altered during the EA effects on DPN.ConclusionsOur results provide the valuable protein biomarkers, which facilitates unique mechanistic insights into the DPN pathogenesis and EA analgesic, antioxidant stress and hypoglycemic effect.

Selective blood-nerve barrier leakiness with claudin-1 and vessel-associated macrophage loss in diabetic polyneuropathy

Diabetic polyneuropathy (DPN) is the most common complication in diabetes and can be painful in up to 26% of all diabetic patients. Peripheral nerves are shielded by the blood-nerve barrier (BNB) consisting of the perineurium and endoneurial vessels. So far, there are conflicting results regarding the role and function of the BNB in the pathophysiology of DPN. In this study, we analyzed the spatiotemporal tight junction protein profile, barrier permeability, and vessel-associated macrophages in Wistar rats with streptozotocin-induced DPN. In these rats, mechanical hypersensitivity developed after 2 weeks and loss of motor function after 8 weeks, while the BNB and the blood-DRG barrier were leakier for small, but not for large molecules after 8 weeks only. The blood-spinal cord barrier remained sealed throughout the observation period. No gross changes in tight junction protein or cytokine expression were observed in all barriers to blood. However, expression of Cldn1 mRNA in perineurium was specifically downregulated in conjunction with weaker vessel-associated macrophage shielding of the BNB. Our results underline the role of specific tight junction proteins and BNB breakdown in DPN maintenance and differentiate DPN from traumatic nerve injury. Targeting claudins and sealing the BNB could stabilize pain and prevent further nerve damage. Key messages • In diabetic painful neuropathy in rats: • Blood nerve barrier and blood DRG barrier are leaky for micromolecules. • Perineurial Cldn1 sealing the blood nerve barrier is specifically downregulated. • Endoneurial vessel-associated macrophages are also decreased. • These changes occur after onset of hyperalgesia thereby maintaining rather than inducing pain. Graphical abstract

Role of Acupuncture in the Management of Diabetic Painful Neuropathy (Dpn): A Pilot Rct

Aims To examine the role of acupuncture in the treatment of diabetic painful neuropathy (DPN) using a single-blind, placebo-controlled RCT and to collect data that would be required in a future definitive study of the efficacy of acupuncture in DPN. Methods 45 patients were allocated to receive a 10-week course either of real (53%) or sham (47%) acupuncture. Five standardised acupuncture points on the lower limb of each leg were used in the study: LR3, KI3, SP6, SP10 and ST36. Outcome measures included the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) scale, lower limb pain (Visual Analogue Scale, VAS); Sleep Problem Scale (SPS); Measure Yourself Medical Outcome Profile (MYMOP); 36-item Short Form 36 Health Survey and resting blood pressure (BP). Results Over the 10-week treatment period, small improvements were seen in VAS −15 (−26 to −3.5), MYMOP −0.89 (−1.4 to −0.3), SPS −2.5 (−4.2 to −0.82) and resting diastolic BP −5.2 (−10.4 to −0.14) in the true acupuncture group. In contrast, there was little change in those receiving sham acupuncture. A moderate treatment effect in favour of active acupuncture was detected in MYMOP scores −0.66 (−0.96 to −0.35) but non-significant effect sizes in LANSS Pain Scale −0.37 (−2.2 to 1.4), resting diastolic BP −0.50 (−3.0 to 1.99) and the SPS −0.51 (−2.2 to 1.16). Conclusions We have demonstrated the practicality and feasibility of acupuncture as an additional treatment for people with DPN. The treatment was well tolerated with no appreciable side effects. Larger randomised trials are needed to confirm the clinical and cost-effectiveness of acupuncture in the treatment of DPN. Trial Registration Number ISRCTN number: 39740785.