[The influence of lumbar sympathetic ganglion radiofrequency thermocoagulation on the activation of microglia in rats with diabetic neuropathic pain]

OBJECTIVE

To observe the influence of lumbar sympathetic ganglion radiofrequency thermocoagulation on the activation of spinal microglia in rats with diabetic neuropathic pain (DNP).

METHODS

Thirty-six painful diabetic Sprague-Dawley rats induced by 60 mg/kg streptozotocin (STZ) intraperitoneal injection were randomly divided into diabetic neuropathic pain group (group DNP, n=12), Sham operation group (group Sham, n=12) and radiofrequency thermocoagulation group (group R, n=12). Meanwhile another 12 age-matched rats were allocated as normal control group (group N), rats in group N received intraperitoneal injection of equal volume of normal saline. Twenty-eight days after STZ injection, rats in group R received L3 lumbar sympathetic ganglia radiofrequency thermocoagulation on the left side under X-ray guideline after anesthesia with damage time 60 s and damage temperature 60 ℃. Rats in group Sham received puncture positioning, but not thermocoagulation therapy. The mechanical paw withdrawal threshold (PWT) were performed before STZ injection, 7, 14, 21, 28 days after STZ injection and 1, 3, 5, 7, 14 days after radiofrequency thermocoagulation, respectively. Blood glucose were performed before STZ injection, 3, 28 days after STZ injection and 1, 14days after radiofrequency thermocoagulation. After the final behavioral testing, L3-L5 spinal cord tissues were removed to exam the expression of microglia marker OX42 by Western blotting and immunofluorescence technique, and the changes in the expression of inflammation factor IL-1β, IL-6, TNF-α were detected by ELISA technique.

RESULTS

Compared with group N, after 14, 21, 28 days of STZ injection and 1, 3, 5, 7, 14 days of radiofrequency thermocoagulation, the PWT of group DNP and group Sham decreased significantly (P<0.05); Before radiofrequency thermocoagulation, the PWT of rats in group DNP was (3.84±0.83) g, the PWT of rats in group R was (4.45±0.88) g, there was no statistically significant difference between group DNP and group R (t=1.514, P>0.05), but after radiofrequency thermocoagulation, compared with DNP group, the PWT of rats in group R increased significantly (P<0.05), and lasted to 14 d after radiofrequency thermocoagulation. The ratio of spinal microglia marker OX42 and GAPDH, the expression of inflammation factor IL-1β, IL-6, and TNF-α in group N were 0.074±0.023, (35.93±6.16) pg/ml, (92.11±13.23) pg/ml, and (169.50±22.64) pg/ml, respectively. The ratio of spinal microglia marker OX42 and GAPDH, the expression of inflammation factor IL-1β, IL-6, and TNF-α in group DNP were 1.023±0.185, (73.82±9.25) pg/ml, (155.33±21.82) pg/ml, and (298.30±33.21) pg/ml, respectively. The ratio of spinal microglia marker OX42 and GAPDH, the expression of inflammation factor IL-1β, IL-6, and TNF-α in group Sham were 0.951±0.103, (73.00±7.54) pg/ml, (151.02±24.26) pg/ml, and (294.01±36.37) pg/ml, respectively. The ratio of spinal microglia marker OX42 and GAPDH, the expression of inflammation factor IL-1β, IL-6, and TNF-α in group R were 0.563±0.019, (51.81±7.36) pg/ml, (123.24±16.13) pg/ml, and (229.23±29.16) pg/ml, respectively. Compared with group N, the expression of spinal microglia marker OX42 and inflammation factor IL-1β, IL-6, and TNF-α in group DNP, group Sham and group R increased significantly (F=7.501, 348.698, 568.021, 145.110, all P<0.05). Compared with DNP group, the expression of spinal microglia marker OX42 and inflammation factor IL-1β, IL-6, and TNF-α of group R reduced significantly (all P<0.05).

CONCLUSION

The lumbar sympathetic ganglion radiofrequency thermocoagulation can alleviate diabetic neuropathic pain. The mechanism may relate with the inhibition of spinal microglia activation and the lower expression of inflammation factor.

[Recurrent syncope related to catecholaminergic polymorphic ventricular tachycardia due to de novo RyR2-R2401H mutation]

Objective: To explore the clinical and molecular genetic features of a Chinese patient with catecholaminergic polymorphic ventricular tachycardia (CPVT). Methods: Clinical data including resting electrocardiography, echocardiography and treadmill exercise testing of a patient with CPVT admitted to our department in March 2013 were analyzed, and the peripheral venous blood samples of the patient and his family members and 400 ethnicity-matched healthy controls were obtained. All exons and exon-intron boundaries of the six CPVT-related genes including RYR2, CASQ2, TRDN, CALM1, KCNJ2 and ANKB were sequenced to detect the variants related to CPVT. The relationship between the genotypes and phenotypes was analyzed to direct the target therapy. Results: Recurrent syncope induced either by exercise or extreme frightened fear was observed in this patient. There was no positive family history of syncope or sudden death. The resting electrocardiography and echocardiography of the patient were normal, while the exercise testing revealed bidirectional and polymorphic ventricular tachycardia. A cardiac ryanodine receptor gene mutation (R2401H) was identified in this patient, while this mutation was absent in his parents and sister and 400 controls. No variant was detected in the remaining five candidate genes. Treatment with high dose of metoprolol succinate (118.75 mg/d) was effective and patient was free of syncopal attack during the 2 years follow-up. Conclusion: This is the first report on RyR2-R2401H mutation in Chinese patient with CPVT, and high dose of metoptolol is the effective therapy option for CPVT related to RyR2 mutation.