Qing Ji

The Effect of Hydrogen-Rich Saline on the Brain of Rats with Transient Ischemia

BACKGROUND Due to its antioxidant and anti-inflammatory properties, hydrogen gas (H(2)) has protective effects on a variety of organs from damage induced by ischemia/reperfusion (I/R). In this study, we tested the protective effect of hydrogen-rich saline on the brain in a global cerebral I/R model. MATERIALS AND METHODS We used a four-vessel occlusion model of global cerebral ischemia (15 min) and reperfusion with rats. The rats were divided into four groups (n = 96): sham, I/R plus physiologic saline injected intraperitoneally, I/R plus hydrogen-rich saline injected intraperitoneally at the beginning of reperfusion, and I/R plus hydrogen-rich saline injected intraperitoneally 6 h after reperfusion began. One group of rats was sacrificed after 24 h of reperfusion. Malondialdehyde (MDA) was measured to quantify the oxidative stress. Caspase-3 was measured to indicate the status of apoptosis. Tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and nuclear factor-κB (NF-κB) were measured to monitor the inflammation. Another group of rats was sacrificed after 72 h of reperfusion to measure the histologic damages in hippocampus by hematoxylin and eosin staining and Nissl staining. RESULTS Compared with rats with I/R only, hydrogen-rich saline treatment significantly improved the amount of surviving cells. NF-κB, TNF-α, IL-6, MDA, and caspase-3 were all increased significantly by I/R injury. Hydrogen-rich saline reduced all these markers. CONCLUSIONS Our data demonstrate that intraperitoneal injection of hydrogen-rich saline has strong protective effect on the transient global cerebral ischemia-reperfusion rats.

Spinal neuroimmune activation inhibited by repeated administration of pioglitazone in rats after L5 spinal nerve transection

Neuroimmune activation contributes to the generation and maintenance of neuropathic pain after peripheral nerve injury. Peroxisome proliferator activated receptor gamma (PPAR-γ) agonists have potential neuroprotection. The current study aimed to determine the effects of a PPAR-γ agonist pioglitazone on mechanical hyperalgesia and neuroimmune activation in a rat model of neuropathic pain induced by L5 spinal nerve transection (SNT). Thirty-two rats were equally randomized into 4 groups: sham operation with vehicle; L5 SNT with vehicle or pioglitazone; or L5 SNT with pioglitazone and a PPAR-γ antagonist GW9662. Pioglitazone or vehicle was administered 1h before operation and continued daily to day 14 after operation. The paw pressure threshold (PPT) was measured before operation and on days 3, 7, 14 after operation. Glial fibrillary acidic protein (GFAP) expression, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 levels, and nuclear factor-kappa B (NF-κB) activity in the lumbar spinal cord were determined on day 14 after operation. The results displayed pioglitazone improved the mechanical hyperalgesia, and attenuated the astrocyte and NF-κB activation and the inflammatory cytokine upregulation in nerve-injured rats, which might be reversed by GW9662. In conclusion, pioglitazone ameliorates the mechanical hyperalgesia induced by L5 SNT via inhibiting the spinal neuroimmune activation in rats, suggesting spinal PPAR-γ signaling pathway may be involved in the pathogenesis of mechanical hyperalgesia.

Repeated administration of pioglitazone attenuates development of hyperalgesia in a rat model of neuropathic pain.

Recent studies indicate the central neuroimmune and neuroinflammation activation play a critical role in the pathological states of pain. Pioglitazone, a potent synthetic agonists of PPARgamma, has shown to control neuroinflammation in many nervous system-related disorders. The present study was designed to explore the effects of pioglitazone in treating neuropathic pain and its possible neuroimmune mechanisms in the neuropathic pain using lumbar 5 (L5) spinal nerve transection rat model. L5 spinal nerve transection was done to produce hyperalgesia in rats. Pioglitazone (2.5, 5, and 10 mg/kg) was orally administered daily for 14 days, beginning from 1 hour before nerve transection. Mechanical hyperalgesia was measured using Von-Frey filament tests before and after the surgery. Rats were then sacrificed on day 14 postsurgery. The mRNA of inflammatory cytokines such as tumor necrosis factor (TNF-alpha), interleukin (IL-1beta) and nuclear factor kappa B (NF-kappaB) activity in brain were detected using reverse transcription-polymerase chain reaction and electrophoretic mobility shift assay. We found that pioglitazone (5 and 10 mg/kg) can markedly attenuate mechanical hyperalgesia produced by nerve transection, most significantly on the 14th day. The elevated TNF-alpha, IL-1beta, and NF-kappaB in brain were accordingly reduced. Our data could conclude that pioglitazone has ameliorative potential in attenuating the painful state associated with L5 nerve transection, which may further be attributed to inhibiting cerebral proinflammatory cytokines production and NF-kappaB activation in central nervous system.

Pentoxifylline Decreases Up-Regulated Nuclear Factor kappa B Activation and Cytokine Production in the Rat Retina following Transient Ischemia

Aim: To investigate whether pentoxifylline (PTX) could influence the increased cytokine gene expression in the retina flowing transient ischemia, and if so, whether it acts through the modulation of nuclear factor kappa B (NF-ĸB) activation. Methods: Sprague-Dawley rats were randomly divided into three equal groups: control group, saline-treated group, and PTX-treated group. Increased intraocular pressure was applied for 90 min to induce retinal ischemia, and reperfusion was established by lowering the bottle to eye level. The reperfusion period lasted for 48 h. In the PTX-treated group, an initial dose of 20 mg PTX was injected via tail vein at the beginning of reperfusion. Then the rat received infusion of PTX at a rate of 6 mg/kg/h throughout the entire reperfusion period. The retinal tissues were collected at the end of 1, 6, 12, 24, and 48 h of reperfusion, respectively, for biochemical analysis. Histological examination was done on the tissues collected at the end of 48 h after reperfusion. Results: Histological examination revealed reduction of overall retinal thickness and thinning of the inner retinal layer in saline-treated rats after 48-hour reperfusion. However, PTX treatment significantly reduced the loss of overall retinal thickness and thinning of inner retinal layers. Dramatic increase in NF-ĸB activation, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) production and mRNA expression were observed in the saline-treated group after reperfusion, with the peak reached around 12 h. In the PTX-treated group, NF-ĸB activation, TNF-α and IL-1β production and mRNA expression were significantly reduced at each corresponding time point compared to the saline-treated group. Conclusion: PTX decreased the up-regulated activation of NF-ĸB and the expression of proinflammatory cytokines, TNF-α and IL-1β in rat retinas following ischemia/reperfusion. This may contribute to significantly reduce the loss of overall retinal thickness and thinning of inner retinal layers.

Intrathecal injection of phosphodiesterase 4B-specific siRNA attenuates neuropathic pain in rats with L5 spinal nerve ligation

Phosphodiesterase 4 (PDE4) is an adenosine cyclic 3,5-monophosphate-specific degradative enzyme, which is closely associated with the inflammatory response. Among its four subtypes (A-D), it remains unclear which one exerts suppressive effects on inflammation and reduces neuropathic pain. The present study aimed to examine the modulation of neuroinflammation by PDE4 subtypes in the spinal cord of a rat model of L5 spinal nerve ligation (SNL)-induced neuropathic pain. The expression levels of PDE4A-D were measured in the lumbar spinal cords of naïve rats. The rats were then divided into seven groups: The sham group (sham surgery + saline), the saline group (SNL + saline), the vehicle group (SNL + Lipofectamine® RNAiMAX), the mismatch small interfering (si)RNA group (SNL + mismatch siRNA), the PDE4A-siRNA group (SNL + PDE4A-siRNA), the PDE4B-siRNA group (SNL + PDE4B-siRNA) and the PDE4D-siRNA group (SNL + PDE4D-siRNA). In order to determine behavioral changes, mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were recorded. The mRNA and protein expression levels of PDE4s were also detected. Furthermore, the association between behavioral changes and individual subtypes of PDE4 were studied following intrathecal administration of PDE4A, B and D-specific siRNA. The expression levels of protein kinases, including phosphorylated-extracellular signal-regulated kinases (p-ERK), and inflammatory cytokines were measured, in order to explore the underlying mechanisms. Subtypes A, B and D, but not C, were detected in the naïve rats. After SNL, both MWT and TWL were reduced. The mRNA and protein expression levels of PDE4A, B and D were significantly upregulated after 2, 4, 6 and 8 days of SNL. Subtype-specific siRNA significantly suppressed the elevated expression levels; however, only rats treated with PDE4B siRNA exhibited improved MWT and TWL. Further analysis of the PDE4B siRNA-treated rats demonstrated that 8 days after SNL, the intensity of p-ERK was reduced, the expression levels of CD11b and glial fibrillary acidic protein GFAP were reduced, as well as the expression levels of proinflammatory cytokines such as tumor necrosis factor-α, interleukin (IL)-1β and IL-6. These results suggested that selective inhibition of PDE4B may relieve neuropathic pain, potentially via the suppression of glial activation and the release of cytokines in the spinal cord.

Differences in the expression of long noncoding RNAs at different time points in the PTSD-like syndrome rat hippocampus

The aim of this study was to characterize the expression profiles at different time points in the PTSD-like syndrome rat hippocampus and perform analyses. PTSD rat models were made as reported by Rau, and we collected the hippocampus at different time points. The lncRNAs at different time points were compared by microarray and listed. We used quantitative real-time PCR to confirm the lncRNA profiling expression data. Bioinformatics analysis was performed on EU056364_P1. Compare with control, a total of 948 lncRNAs and 2514 mRNAs were found (fold-change > 2.0) among the four time points. Additionally, bioinformatics analysis of EU056364_P1 suggested it might be involved in memory development through the target gene Camk2a.This study revealed different lncRNAs expressed at different time points in PTSD and explored the targets of PTSD.