Analgesic Effect and Mechanism of Osteoking on Dorsal Root Ganglion Compression Model Rats / 中国实验方剂学杂志

ObjectiveTo investigate the analgesic effect and mechanism of Osteoking （OK） on nerve compression in lumbar disc herniation. MethodThe rat model of chronic compression of dorsal root ganglion （CCD） was established to simulate clinical lumbar disc herniation. The CCD rats were randomly divided into model group， low， medium， and high dose OK groups （1.31， 2.63， 5.25 mL·kg-1·d-1）， and pregabalin group （5 mg·kg-1）， with eight rats in each group. Another eight SD rats were taken as the blank group， and the same volume of normal saline was given by gavage. Behavioral tests， side effect evaluation， network analysis， Western blot， immunofluorescence， and antagonist application were used to explore the effect. ResultCompared with the blank group， the mechanical hyperalgesia threshold， thermal hyperalgesia threshold， and the expression of inflammatory factors in the spinal dorsal horn of the model group are significantly increased （P<0.01）， and the related indicators of the affected foot footprints are significantly down-regulated （P<0.01）. The expression of signal transducer and activator of transcription 3 （STAT3）， vascular endothelial growth factor A （VEGFA）， and phosphorylated extracellular regulated protein kinase （p-ERK） in microglia in the spinal dorsal horn is significantly increased in the model group （P<0.01）. Compared with the model group， low， medium， and high dose OK groups can increase the mechanical hyperalgesia and thermal hyperalgesia thresholds of CCD rats （P<0.05， P<0.01） in a dose-dependent manner， improve the gait of CCD rats （P<0.05， P<0.01）， and reduce the expression of inflammatory factors in the spinal dorsal horn （P<0.05， P<0.01）. The expression of STAT3， VEGFA， and p-ERK in the spinal dorsal horn microglia of CCD rats is significantly decreased （P<0.05， P<0.01）， and the acetic acid-induced nociceptive response in rats is effectively reduced （P<0.05， P<0.01）. In addition， there is no tolerance. The results of the body mass test， organ index， forced swimming， and rotation show that OK has no obvious toxic or side effects. Further antagonist experiments show that MRS1523 and RS127445 can reverse the transient analgesic effect of OK compared with the high dose OK group （P<0.01）. ConclusionOK has a good analgesic effect on the CCD model without obvious toxic side effects， and its mechanism may be related to the activation of ADORA3 and HTR2B and the inhibition of STAT3， VEGFA， p-ERK， and other elements in microglia.

Expression and significance of PAR2 and TMEM16A on DRG rat modelin of neuropathic pain / 实用医学杂志

Objective To observe the expression of PAR2 and TMEM16A in the model of chronic constriction injury (CCI) in rat dorsal root ganglion (DRG) neurons,and to explore the role of it in the neuropathic pain.Methods Rats were divided into Sham operation group (Sham) and CCI group.Both groups were observed respectively to determine thermal withdrawal latency (TWL).The expression of PAR2 and TMEM16A in the dorsal root ganglion of the rat was analyzed using Western blot and immunofluorescence.Results The difference in preoperative TWL between CCI group and Sham group rats was not statistically significant (P ＜ 0.01).TWL was signifi cantly lower at all other time points after operation (P ＜ 0.01).Immunofluorescence results showed that PAR2 and TMEM16A coexisted in rat DRG neurons.Western blot results showed that,compared with Sham group,CCI group PAR2 and TMEM16A protein expression significantly increased after 7 d and 14 d (P ＜ 0.01),and the PAR2 and TMEM16A protein expression on 14 d is higher than that of 7 d (P ＜ 0.05).Conclusions Expression level of PAR2 and TMEM16A in CCI group was significantly higher than those in Sham group.The expression level of these proteins may be the cause of rat model of neuropathic pain.

Effect of reactive oxygen species on dorsal root ganglion P2X3 receptor-induced pain signal / 第二军医大学学报

Objective To investigate the effect of reactive oxygen species(ROS) on P2X3 receptor-mediated neuropathic pain. Methods Neuropathic pain model was induced in female Sprague Dawley rats by chronic compression of dorsal root ganglia (CCD), and the CCD rats were randomly divided into 4 groups (each group containing 10 rats): Saline group (NS group); PBN 100 mg/kg treatment group; PBN 30 mg/kg treatment group; and PBN 10 mg/kg treatment group. The specific agonist of P2X3 receptor, α, β-meATP (50 nmol in 50 μL), was subcutaneously injected into the plantar surface of the right hind paws of each rat 30 minafter PBN or NS injection. The spontaneous paw flinching times and withdrawing time were observed for 15 min after injection and the paw lift time per minute (PLTPM) in every 2 minutes was calculated. Results Pre- treatmentwith PBN inhibited α, β-meATP-induced spontaneous pain in a dose-dependent manner. Compared with the NS group, PBN 100 mg/kg group significantly inhibited flinching response during the first 6 min (P<0. 05), while the rats in PBN 30 mg/kg group only had significantly attenuated flinching response during the second to the fourth minute compared with NS group(P<0. 05). Conclusion Oxygen free radical scavenger can effectively alleviate the neuropathic pain caused by CCD and P2X3 receptor agonist-induced spontaneous pain. ROS may act as a messenger in P2X3 receptor-mediated pain signaling transmission.

Expression and role of connective tissue growth factor in the peripheral nerve after chronic compression injury / 中华显微外科杂志

Objective To investigate the effects of connective tissue growth factor (CTGF) on the chronic peripheral nerve compression injury and explore the function of CTGF in peripheral nerve compression injury and repair. Methods From July 2010 to September 2010, fifty aduh male SD rats were randomly divided into group A and B: group A (sham-operated group): only exposed the sciatic nerve; group B (compression group): undergone sciatic nerve entrapment operation on the right hind leg according to the method which Mackinnon adopted when he established the model of chronic sciatic nerve compression.Electron microscopy,immunohistochemistry,RT-PCR and Western-blot were performed to observe the morphological changes of the compressed nerve tissue and to determine the level of CTGF,collagen- Ⅰ,Ⅲ (COL- Ⅰ,Ⅲ),2,4,6,8,10 weeks after the surgery,respectively. Results After sciatic nerve compression,the collagen in nerve increased ; The expression of CTGF and COL- Ⅰ, Ⅲ in sciatic nerve of compressed group increased, which was statistically different compared with the sham-operation group (P ＜ 0.05); In the meanwhile,the contents of CTGF and COL- Ⅰ,Ⅲ were positively correlated in a certain period. Conclusion Peripheral nerve fibrosis can be caused by chronic nerve compression.The expression of COL- Ⅰ,Ⅲ in sciatic nerve increased and CTGF get involved in the pathophysiological process, which suggests that CTGF plays an important role in the process of neural injury and fibrosis.

Effect of sympathetic nerve on the expression of substance P mRNA in dorsal root ganglion of chronically compressed brachial plexus / 中华显微外科杂志

Objective To investigate the effect of different function of sympathetic nerve on the pain of peripheral nerve chronic compression. Methods Forty-eight male Sprague-Dawley rats were made into lower trunk chronic compression models and divided into 6 groups (A1,B1,C1,A2,B2,C2) with 8 rats per group. The C8T1 dorsal root ganglions of the compressed sides of group A1 (control group), B1 (sympathetic block group)and C1 (de-sympathetic group) were harvested 3 months after compression surgery. The compressed lower trunks of group A2 (control group), B2(sympathetic block group)and C2(de-sympathetic group)were decompressed 3 months after compression surgery and bred for another month and then the C8T1 dorsal root ganglions of the compressed sides were harvested. The levels of substance P mRNA in the C8T1 dorsal root ganglions were tested with RT-PCR technique. Results the mean relative levels of substance P mRNA of group A1, B1 and C1 were (3.620 ± 0.830) × 10-2, (2.945 ± 0.724) × 10-2, (2.239 ± 0.734) × 10-2, respectively, with a significant difference (P = 0.006) and those of group A2, B2 and C2 were (3.163 ± 1.026) × 10-2, (2.355 ± 0.680) × 10-2,(1.487 ± 0.802) × 10-2, the difference among which was statistically significant (P = 0.003). Conclusion The pain of peripheral nerve chronic compression is affected by sympathetic function. The more lower the sympathetic function is, the more light the pain is. Sympathetic blockage or resection helps to relieve the pain of peripheral nerve compression disease after being decompressed.

An Experimental Model of Chronic Nerve Compression in the Rat / 대한정형외과학회잡지

PURPOSE: The aim of this study was to develop a model for chronic nerve compression in a rat and a model reproducing a normal anatomical narrow portion that lies in the course of the peripheral nerve. MATERIALS AND METHODS: Male Sprague-Dawley rats were used. A 5 mm tendinous band was made from the patellar tendon harvested from each rat and placed around the sciatic nerve. In order to determine the degree of compression, a series of internal diameters of the band (0.2 mm smaller than (group I), same as (group II), and 0.2 mm (group III), 0.4 mm (group IV) and 0.6 mm greater (group V) than the diameter of sciatic nerve) were used. The rats were evaluated at 1, 2, 3, 4, and 6 months after banding using an electroneurophysiologic study, a pathohistologic study, and the morphometric nerve fiber analysis. RESULTS: In groups III and IV the morphometric findings showed statistically significant compressive changes in the periphery after 3 and 4 months, respectively and revealed significant changes in both the periphery and central portion at 6 months (p<0.05). In group V, the measurements and histologic findings were almost identical to the control group at 6 and 10 months. The nerve electrophysiologic study showed significant compressive changes at 6 months in groups III and IV (p<0.05). In the group V, the measurements were similar to those of the normal control. CONCLUSION: Groups III and IV appear to be a reliably reproducible chronic nerve compression model while excluding the possibility of foreign body reactions. In addition, group V appears to be a reliable model of a normal anatomical narrow portion that lies in the course of the peripheral nerve.

Epidural Hyaluronic Acid in a Rat Model of Chronic Dorsal Root Ganglion Compression / 대한마취과학회지

BACKGROUND: Hyaluronic acid (HA) is a naturally occurring polysaccharide that has been shown to be beneficial in various clinical settings, such as in opthalmic surgery or for intra-articular injections. This study was designed to evaluate the effect of epidurally injected HA as an agent for decreasing pain in an animal model of chronic dorsal root ganglion compression. METHODS: A small stainless steel rod was inserted into L4-5 intervertebral foramen in the rat, to develop intervertebral foramen stenosis and chronic DRG compression. Twenty-seven rats were assigned to the saline group (n = 9), HA group (n = 9), or the no treatment (control) group (n = 9). In the saline group and the HA group, 0.1 ml of 0.9% saline and the same volume of HA were injected into the epidural space through an epidural catheter. Behavioral tests for thermal hyperalgesia was performed for five weeks after epidural injection. RESULTS: The hindpaw on the injured side in the control group and in the saline group showed a significant reduction in the latency of foot withdrawal to noxious heat. Rats in the HA group showed a significant reduction of hyperalgesia in the thermal test (P < 0.05). CONCLUSIONS: Our findings suggest the epidurally administered HA may be effective for relieving lumbar radicular pain and low back pain produced by chronic DRG compression in the clinical setting.

The morphologic changes of dorsal root ganglion after lumbar nerve root being under chronic compression and inflammatory stimulation in rabbits / 中华物理医学与康复杂志

Objective To observe the morphologic changes of dorsal root ganglion in the lumbar region of rabbits after the nerve root was under chronic compression and inflammatory stimulation. Methods Twenty New Zealand rabbits were recruited for this study, of which 5 served as the control (control group), and the rest were randomized into 3 experimental subgroups: 10d group, 30d group, 90d group, respectively. The autologous nucleus pulposus from the tails (about 5mg) was put into the silastic tube (inner meter of 1.5mm, external diameter 2.5mm and length 12mm), which was inserted into the left L 7 intervertebral foramen to compress the lumbar nerve root. Sham operation was performed with the rabbits in the control group. The nerve root and the dorsal root ganglia were harvested and processed and observed with light microscope and electron microscope after 10d, 30d, 90d, respectively. Results In the 10d group, obvious hyperemia, edema and infiltration of inflammatory cells in the interspace of the intima of the dorsal root ganglia (DRG) could be observed. Pyknosis, degeneration and necrosis were also found in some of the nerve cells. Electron microscopic observation showed that the number of the rough endoplasmic reticulum and mitochondrion decreased, ribosome exfoliated, mitochondrion swelled. In 30d group, typical degeneration and necrosis became more obvious. Electron microscope showed that the number of lysosome and smooth endoplasmic reticulum increased, mitochondrion swelled and its cristae disappeared, nuclei concentrated and deviated. In 90d group, significant proliferation of fibrocyte could be observed. At the same time, dura mater and arachnoid of spinal cord around the nerve root were notably thickened, and became fibrogenesis. Electron microscope also showed the increment of the lysosome and smooth endoplasmic reticulum, the swelling of mitochondrion, the loss of its cristae and the concentration of the nucleolus in the central part of the nuclei. No significant changes were found in the control group. Conclusion Pathological changes of neural degeneration such as edema, inflammatory infiltration could be observed in dorsal root ganglion after the nerve root was under chronic compression and stimulation by autologous nucleus pulposus.

The role of p38MAPK of spinal cord in the neuropathic pain following chronic compression of dorsal root ganglion of rats / 中国药理学通报

Aim To investigate the changes of phosphorylated p38 mitogen-activated protein kinase(p-p38MAPK)in the spinal cord following chronic compression of dorsal root ganglion(CCD)in rats, and to explore the correlation between chronic neuropathic pain and p38MAPK.Methods The animal model of neuropathic pain following chronic compression of dorsal root ganglion was established.36 male Sprague-Dawley rats were randomly divided into Naive group(n=4),Sham group(n=16),CCD group(n=16).Sham group and CCD group were also divided into 5,7,14 d and 21 d group respectively(n=4),Western blot analysis was used to investigate the expression of the phosphorylated active form of p38MAPK (p-p38MAPK) in the spinal dorsal horn in rats after CCD.Results p-p38MAPK protein was expressed in spinal cord among all three groups,but there were no significant differences between Naive group and Sham group.Compared to Naive and Sham group, rats in CCD group showed significant increase of the expression of p-p38MAPK protein in spinal cord.Compared with that of Sham group,protein expression of p-p38MAPK in cytosol in the spinal dorsal horn in 5,7,14 d and 21 d of post-surgery increased respectively 138.1%(P