Progression of Cartilage Degradation, Bone Resorption and Pain in Rat Temporomandibular Joint Osteoarthritis Induced by Injection of Iodoacetate

Background

Osteoarthritis (OA) is an important subtype of temporomandibular disorders. A simple and reproducible animal model that mimics the histopathologic changes, both in the cartilage and subchondral bone, and clinical symptoms of temporomandibular joint osteoarthritis (TMJOA) would help in our understanding of its process and underlying mechanism.

Objective

To explore whether injection of monosodium iodoacetate (MIA) into the upper compartment of rat TMJ could induce OA-like lesions.

Methods

Female rats were injected with varied doses of MIA into the upper compartment and observed for up to 12 weeks. Histologic, radiographic, behavioral, and molecular changes in the TMJ were evaluated by light and electron microscopy, MicroCT scanning, head withdrawal threshold test, real-time PCR, immunohistochemistry, and TUNEL assay.

Results

The intermediate zone of the disc loosened by 1 day post-MIA injection and thinned thereafter. Injection of an MIA dose of 0.5 mg or higher induced typical OA-like lesions in the TMJ within 4 weeks. Condylar destruction presented in a time-dependent manner, including chondrocyte apoptosis in the early stages, subsequent cartilage matrix disorganization and subchondral bone erosion, fibrosis, subchondral bone sclerosis, and osteophyte formation in the late stages. Nociceptive responses increased in the early stages, corresponding to severe synovitis. Furthermore, chondrocyte apoptosis and an imbalance between anabolism and catabolism of cartilage and subchondral bone might account for the condylar destruction.

Conclusions

Multi-level data demonstrated a reliable and convenient rat model of TMJOA could be induced by MIA injection into the upper compartment. The model might facilitate TMJOA related researches.     

Parallel Induction of Nitric Oxide and Tetrahydrobiopterin Synthesis by Cytokines in Rat Glial Cells

Abstract: Activation of monocyte-derived macrophages with cytokines leads to the induction of nitric oxide synthase. Much less is known about the effects of cytokines on microglia, resident brain macrophages, or on astrocytes. In this study, we compared the induction by lipopolysaccharide, interferon-γ, and tumor necrosis factor-α of nitric oxide production and synthesis of tetrahydrobiopterin, the required cofactor for nitric oxide synthase, in microglia and peritoneal macrophages. Activation of microglia induced parallel increases in nitric oxide and intracellular tetrahydrobiopterin levels, although induction of the latter appears to be somewhat more sensitive to diverse stimulators. As with macrophages, inducible nitric oxide production in microglia was blocked by inhibitors of tetrahydrobiopterin biosynthesis. Interleukin-2, an important component of the neuroimmunomodulatory system, was only a weak activator of microglia by itself but potently synergized with interferon-γ to stimulate production of both nitric oxide and tetrahydrobiopterin. Astrocytes were also activated by lipopolysaccharide and combinations of cytokines but showed a somewhat different pattern of responses than microglia. Biopterin synthesis was increased to higher levels in astrocytes than in microglia, but maximal induction of nitric oxide production required higher concentrations of cytokines than microglia and the response was much lower. These results suggest that tetrahydrobiopterin synthesis in glial cells is a potential target for therapeutic intervention in acute CNS infections whose pathology may be mediated by overproduction of nitric oxide.     

微生物法高产辅酶Q10的研究进展

辅酶Q10是呼吸链上的一种电子传递体,具有抗氧化功能.微生物法生产辅酶Q10具有产物活性高、原料成本低并可以通过规模放大提高生产能力等优点.综述了微生物法生产辅酶Q10的生产菌种,以及能够提高辅酶Q10产量的各种不同的方法策略.     

Attenuation of Cocaine and Methamphetamine Neurotoxicity by Coenzyme Q10

The neurotoxic effects of cocaine and methamphetamine (METH) were studied in mice brain with a primary objective to determine the neuroprotective potential of coenzyme Q₁₀ (CoQ₁₀) in drug addiction. Repeated treatment of cocaine or METH induced significant reduction in the striatal dopamine and CoQ₁₀ in mice. Cocaine or METH-treated mice exhibited increased thiobarbituric acid reactive substances (TBARs) in the striatum and cerebral cortex without any significant change in the cerebellum. Complex I immunoreactivity was inhibited in both cocaine and METH-treated mice, whereas tyrosine hydroxylase (TH) immunoreactivity was decreased in METH-treated mice and increased in cocaine-treated mice. Neither cocaine nor METH could induce significant change in α-synuclein expression at the doses and duration we have used in the present study. CoQ₁₀ treatment attenuated cocaine and METH-induced inhibition in the striatal ¹⁸F-DOPA uptake as determined by high-resolution microPET neuroimaging. Hence exogenous administration of CoQ₁₀ may provide neuroprotection in drug addiction.     

微生物发酵法生产辅酶Q10研究进展

微生物发酵法是生产辅酶Q10很有前景的方法.本文综述了辅酶Q10产生菌的种类、生物合成机制、辅酶Q10产生菌的改良以及发酵条件优化等方面的研究进展.     

Down-Regulation of Neuronal Nitric Oxide Synthase by Nitric Oxide After Oxygen-Glucose Deprivation in Rat Forebrain Slices

Abstract : The precise role that nitric oxide (NO) plays in the mechanisms of ischemic brain damage remains to be established. The expression of the inducible isoform (iNOS) of NO synthase (NOS) has been demonstrated not only in blood and glial cells using in vivo models of brain ischemia-reperfusion but also in neurons in rat forebrain slices exposed to oxygen-glucose deprivation (OGD). We have used this experimental model to study the effect of OGD on the neuronal isoform of NOS (nNOS) and iNOS. In OGD-exposed rat forebrain slices, a decrease in the calcium-dependent NOS activity was found 180 min after the OGD period, which was parallel to the increase during this period in calcium-independent NOS activity. Both dexamethasone and cycloheximide, which completely inhibited the induction of the calcium-independent NOS activity, caused a 40-70% recovery in calcium-dependent NOS activity when compared with slices collected immediately after OGD. The NO scavenger oxyhemoglobin produced complete recovery of calcium-dependent NOS activity, suggesting that NO formed after OGD is responsible for this down-regulation. Consistently, exposure to the NO donor ( Z )-1-[(2-aminoethyl)- N -(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETA-NONOate) for 180 min caused a decrease in the calcium-dependent NOS activity present in control rat forebrain slices. Furthermore, OGD and DETA-NONOate caused a decrease in level of both nNOS mRNA and protein. In summary, our results indicate that iNOS expression down-regulates nNOS activity in rat brain slices exposed to OGD. These studies suggest important and complex interactions between NOS isoforms, the elucidation of which may provide further insights into the physiological and pathophysiological events that occur during and after cerebral ischemia.     

粪便微生物系移植通过影响炎症因子和肠道菌群结构缓解大鼠实验性结肠炎

炎症性肠病（inflammatory bowel disease,IBD）病因虽未明确,但目前认为,肠道细菌和肠黏膜免疫功能紊乱与IBD的发病密切相关。将40只SD大鼠分为健康对照组、模型组、粪便微生物系移植组（fecal microbiota transplantation,FMT）和柳氮磺胺吡啶组,后3组用2,4,6-三硝基苯磺酸（2,4,6-trinitrobenzene sulfonic acid, TNBS）灌肠造模,造模2 d后分别用粪便悬液和柳氮磺胺吡啶治疗1 w。末次给药后禁食1 d,对大鼠粪便进行菌群成分分析,股动脉取血,对K⁺ 、Na⁺ 、血清白蛋白（ALB）、白细胞计数（WBC）、中性粒细胞百分率（N%）、C-反应蛋白（CRP）、IL-1β、IL-10、IL-12和IL-17 水平进行检测,取结肠行病理学检查。结果发现,通过TNBS灌肠成功建立大鼠实验性结肠炎模型。与模型组比较,FMT组的K⁺和ALB明显升高(P<0.05),WBC、N%和CRP明显降低(P<0.05),IL-1β和IL-17明显降低(P<0.05),IL-10和IL-10/IL-12含量升高(P<0.05)。FMT能显著改善TNBS引起的肠道菌群变化,促进双歧杆菌的增殖而抑制脆弱拟杆菌和大肠杆菌的生长。上述结果证明,FMT可有效治疗炎症性肠病,其机制与其影响血清炎症因子水平和改善肠道菌群有关。     

Acupuncture Alleviates the Affective Dimension of Pain in a Rat Model of Inflammatory Hyperalgesia

Although studies demonstrate that electroacupuncture (EA) alleviates the sensory dimension of pain, they have not addressed EA’s effect on the affective dimension. An inflammatory pain rat model, produced by a complete Freund adjuvant (CFA) injection into the hind paw, was combined with a conditioned place avoidance test to determine EA’s effects and its underpinning mechanism on the affective dimension of pain. CFA-injected rats showed place aversion, i.e. the affective dimension of pain, by spending less time in a pain-paired compartment after conditioning than before, while saline-injected rats did not. CFA rats given EA treatment at GB30 before a post-conditioning test showed no aversion to the pain-paired compartment, indicating that EA inhibited the affective response. Intra-rostral anterior cingulate cortex (rACC) administration of a κ-, but not μ-opioid receptor antagonist, blocked EA action. These data demonstrate that EA activates opioid receptors in the rACC to inhibit the affective dimension of pain.     

Emodin Inhibits Inducible Nitric Oxide Synthase in a Rat Model of Craniocerebral Explosive Injury

To investigate the effects of emodin on blast-induced traumatic brain injury (bTBI) in a rat model. Eighty rats were randomly divided into 2 groups (the control group and the emodin-treated group; N = 40 per group) and were used to establish the model of blast-induced traumatic brain injury. Ten minutes after the explosion, an isotonic saline solution (10 mg/kg) or emodin (10 mg/kg) were administered via an intraperitoneal injection to the control group and the emodin-treated group, respectively. At each time point (pre-explosion, 2, 6, 12, 24 h after explosion), 2 rats were used for the pathological assessment and 6 rats were used for the biochemical assessment. The concentration of nitric oxide (NO) and the expression and activity of inducible nitric oxide synthase (iNOS) were measured at each time point by spectrophotometry and western blot analysis. Light and electron microscopy showed that the brain damage in the emodin-treated group was less serious than that observed in the control group. The concentration of NO in the emodin-treated group was lower compared with the control group (p < 0.05). Western blot analysis showed that protein expression in the emodin-treated group was lower than the control group (p < 0.05). Emodin can alleviate brain damage after bTBI by inhibiting iNOS. These findings suggest that emodin has a protective effect against bTBI. One possible mechanism may occur by inhibiting the expression and activity of iNOS and consequently decreasing the concentration of NO.     

Analgesic Effect of Methane Rich Saline in a Rat Model of Chronic Inflammatory Pain

How oxidative stress contributes to neuro-inflammation and chronic pain is documented, and methane is reported to protect against ischemia–reperfusion injury in the nervous system via anti-inflammatory and antioxidant properties. We studied whether methane in the form of methane rich saline (MS) has analgesic effects in a monoarthritis (MA) rat model of chronic inflammatory pain. Single and repeated injections of MS (i.p.) reduced MA-induced mechanical allodynia and multiple methane treatments blocked activation of glial cells, decreased IL-1β and TNF-α production and MMP-2 activity, and upregulated IL-10 expression in the spinal cord on day 10 post-MA. Furthermore, MS reduced infiltrating T cells and expression of IFN-γ and suppressed MA-induced oxidative stress (MDA and 8-OHDG), and increased superoxide dismutase and catalase activity. Thus, MS may offer anti-inflammatory and antioxidant effects to reduce chronic inflammatory pain.     

Coenzyme Q10 Alleviated Behavioral Dysfunction and Bioenergetic Function in an Animal Model of Depression

Neurochemical Research - Coenzyme Q10 (CoQ10) is a natural compound, is involved in the mitochondrial electron transfer chain (ETC) and plays an important pattern in adenosine triphosphate (ATP)...     

Cytokines and Absence Seizures in a Genetic Rat Model

We investigated the role of two cytokines, IL-1β and TNF-α, in the development of absence seizures using a genetic model of absence epilepsy in WAG/Rij rats. We administered these cytokines to animals systemically and measured the number of spike-wave discharges (SWDs) in the EEG. We also coadministered IL-1β with the GABA reuptake inhibitor tiagabine and measured the levels of IL-1β and TNF-α in the brain and blood plasma of 2-, 4-, and 6-month-old WAG/Rij rats and animals that served as a non-epileptic control (ACI). We found that IL-1β induced a significant increase in SWDs 2-5 h after administration, while TNF-α enhanced SWDs much later. Both cytokines enhanced passive behavior; body temperature was elevated only after TNF-α. The action of tiagabine was potentiated by earlier IL-1β injection, even when IL-1β was no longer active. Young WAG/Rij rats showed higher levels of TNF-α in blood serum than young ACI rats; the effects in the brain tended to be opposite. The marked differences in timing of the increase in SWDs suggest different time scales for the action of both cytokines tested. It is proposed that the results found after TNF-α are due to the de novo synthesis of IL-1β. TNF-α may possess neuroprotective effects. IL-1β might increase GABA-ergic neurotransmission. The changes in the efficacy of antiepileptic drugs related to changes in the cytokine systems may have some clinical relevance.     

Coenzyme Q10 production in a 150-l reactor by a mutant strain of Rhodobacter sphaeroides

For the commercial production of CoQ₁₀, batch-type fermentations were attempted in a 150-l fermenter using a mutant strain of R. sphaeroides. Optimum temperature and initial aeration rate were found to be 30°C and 2 vvm, respectively. Under optimum fermentation conditions, the maximum value of specific CoQ₁₀ content was achieved reproducibly as 6.34 mg/g DCW after 24 h, with 3.02 g/l of DCW. During the fermentation, aeration shift (from the adequate aeration at the early growth phase to the limited aeration in active cellular metabolism) was a key factor in CoQ₁₀ production for scale-up. A higher value of the specific CoQ₁₀ content (8.12 mg/g DCW) was achieved in fed-batch fermentation and comparable to those produced by the pilot-scale fed-batch fermentations of A. tumefaciens, which indicated that the mutant strain of R. sphaeroides used in this study was a potential high CoQ₁₀ producer. This is the first detailed study to demonstrate a pilot-scale production of CoQ₁₀ using a mutant strain of R. sphaeroides.     

Enhancement of Coenzyme Q10 Accumulation by Mutation and Effects of Medium Components on the Formation of Coenzyme Q Homologs by Pseudomonas N842 and Mutants

Mutation of Pseudomonas N842 was carried out to increase CoQ₁₀ production. The productivity of CoQ₁₀ was improved considerably by repeated mutation, and the content of CoQ₁₀ per unit cell of the fifth generation mutant was approximately 6 times that of the wild strain, Pseudomonas N842. CoQ₁₁, which was hardly detectable in the wild strain, increased significantly by mutation, and the ratio of CoQ₁₁ to total CoQ exceeded 20% in the fourth generation mutant. Intermittent feeding of glucose to the culture medium during cultivation increased cell yield and CoQ production. When total glucose added was 5 times that of basal medium, cell yield and CoQ formation respectively increased about 3 and 4 times.     

Involvement of Spinal Serotonin Receptors in Electroacupuncture Anti-Hyperalgesia in an Inflammatory Pain Rat Model

We previously showed that electroacupuncture (EA) activates medulla-spinal serotonin-containing neurons. The present study investigated the effects of intrathecal 5,7-dihydroxytryptamine creatinine sulfate, a selective neurotoxin for serotonergic terminals, the 5-hydroxytryptamine 1A receptor (5-HT1AR) antagonist NAN-190 hydrobromide and the 5-HT2C receptor (5-HT2CR) antagonist SB-242,084 on EA anti-hyperalgesia. EA was given twice at acupoint GB30 after complete Freund’s adjuvant (CFA) injection into hind paw. CFA-induced hyperalgesia was measured by assessing hind paw withdrawal latency (PWL) to a noxious thermal stimulus 30 min post-EA. Serotonin depletion and the 5-HT1AR antagonist blocked EA anti-hyperalgesia; the 5-HT2CR antagonist did not. Immunohistochemical staining showed that spinal 5-HT1AR was expressed and that 5-HT2CR was absent in naive and CFA-injected animals 2.5 h post-CFA. These results show a correlation between EA anti-hyperalgesia and receptor expression. Collectively, the data show that EA activates supraspinal serotonin neurons to release 5-HT, which acts on spinal 5-HT1AR to inhibit hyperalgesia.     

微生物发酵产辅酶Q10的高速逆流色谱法分离纯化

本文首次将高速逆流色谱法应用于微生物发酵液提取物中辅酶Q10的分离纯化,建立了一套可用于其制备分离的逆流色谱溶剂体系正庚烷－乙睛－二氯甲烷(12：7：3.5, v/v/v)。500mg发酵液粗提物经一步制备分离,可得到绝对纯度在98％以上辅酶Q10130mg。比较表明,该方法较传统的硅胶柱层析和结晶相结合的纯化方法在产物纯度、回收率及产率等方面都有一定的优势。     

Sequential Change in T2* Values of Cartilage,Meniscus, and Subchondral Bone Marrow in a Rat Model of Knee Osteoarthritis

Background

There is an emerging interest in using magnetic resonance imaging (MRI) T2* measurement for the evaluation of degenerative cartilage in osteoarthritis (OA). However, relatively few studies have addressed OA-related changes in adjacent knee structures. This study used MRI T2* measurement to investigate sequential changes in knee cartilage, meniscus, and subchondral bone marrow in a rat OA model induced by anterior cruciate ligament transection (ACLX).

Materials and Methods

Eighteen male Sprague Dawley rats were randomly separated into three groups (n = 6 each group). Group 1 was the normal control group. Groups 2 and 3 received ACLX and sham-ACLX, respectively, of the right knee. T2* values were measured in the knee cartilage, the meniscus, and femoral subchondral bone marrow of all rats at 0, 4, 13, and 18 weeks after surgery.

Results

Cartilage T2* values were significantly higher at 4, 13, and 18 weeks postoperatively in rats of the ACLX group than in rats of the control and sham groups (p<0.001). In the ACLX group (compared to the sham and control groups), T2* values increased significantly first in the posterior horn of the medial meniscus at 4 weeks (p = 0.001), then in the anterior horn of the medial meniscus at 13 weeks (p<0.001), and began to increase significantly in the femoral subchondral bone marrow at 13 weeks (p = 0.043).

Conclusion

Quantitative MR T2* measurements of OA-related tissues are feasible. Sequential change in T2* over time in cartilage, meniscus, and subchondral bone marrow were documented. This information could be potentially useful for in vivo monitoring of disease progression.     

Nitric Oxide Inhibits Vascular Smooth Muscle Cell Proliferation and Neointimal Hyperplasia by Increasing the Ubiquitination and Degradation of UbcH10

Nitric oxide (NO) limits formation of neointimal hyperplasia in animal models of arterial injury in large part by inhibiting vascular smooth muscle cell (VSMC) proliferation through cell cycle arrest. The ubiquitin-conjugating enzyme UbcH10 is responsible for ubiquitinating cell cycle proteins for proper exit from mitosis. We hypothesize that NO prevents VSMC proliferation, and hence neointimal hyperplasia, by decreasing levels of UbcH10. Western blotting and immunofluorescent staining showed that NO reduced UbcH10 levels in a concentration-dependent manner in VSMC harvested from the abdominal aortas of Sprague-Dawley rats. Treatment with NO or siRNA to UbcH10 decreased both UbcH10 levels and VSMC proliferation (P<0.001), while increasing UbcH10 levels by plasmid transfection or angiotensin II stimulation increased VSMC proliferation to 150% (P=0.008) and 212% (P=0.002) of control, respectively. Immunofluorescent staining of balloon-injured rat carotid arteries showed a ~4-fold increase in UbcH10 levels, which was profoundly decreased following treatment with NO. Western blotting of carotid artery lysates showed no UbcH10 in uninjured vessels, a substantial increase in the injury alone group, and a significant decrease in the injury+NO group (~3-fold reduction versus injury alone). Importantly, in vitro and in vivo, a marked increase in polyubiquitinated UbcH10 was observed in the NO-treated VSMC and carotid arteries, respectively, indicating that NO may be decreasing unmodified UbcH10 levels by increasing its ubiquitination. Central to our hypothesis, we report that NO decreases UbcH10 levels in VSMC in vitro and following arterial injury in vivo in association with increasing polyubiquitinated-UbcH10 levels. These changes in UbcH10 levels correlate with VSMC proliferation and neointimal hyperplasia, making UbcH10 a promising therapeutic target for inhibiting this proliferative disease.