Ethylenediamine pretreatment simultaneously improved carbohydrate hydrolysis and lignin valorization.

Lignocellulosic biomass (LCB) is the promising feedstock for value-added products, which would contribute to the bioeconomy and sustainable development. The efficient pretreatment is still required in the biorefinery of LCB. To make a simultaneous utilization of carbohydrates and lignin, a novel easy-recycled ethylenediamine (EDA) pretreatment was designed and evaluated in the present study. The results highlighted that this pretreatment yielded 96% glucose and 70% xylose in enzymatic hydrolysis. It simultaneously promoted the depolymerization of lignin into small molecules and functionalized the yielded lignin with Schiff base and amide structures. These animated-lignins showed a pH-responsive behavior and the excellent flocculation capacity by reducing more than 90% turbidity of kaolin suspensions. Therefore, easy-recycled EDA pretreatment hold the promise to simultaneously enhance the enzymatic hydrolysis of carbohydrates and endowed the new functionality of lignin toward downstream valorization, which improved the process feasibility and potentially enable the sustainability of LCB utilization.

lncRNA HHIP-AS1/HHIP modulates osteogenic differentiation of BM-MSCs by regulating Hedgehog signaling pathway.

BACKGROUND: lncRNA, a type of non-coding RNA, plays an important role in the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BM-MSCs). In this study, lncRNA and mRNA microarrays were performed to study the change of gene expression during osteogenic differentiation of BM-MSCs. We focused on Hedgehog interacting protein (HHIP), because HHIP mRNA and lncRNA HHIP-AS1 were gradually down-regulated on days 0, 7, and 14 during osteogenic differentiation. In addition, the gene coding lncRNA HHIP-AS1 is located on the anti-sense of Hhip gene, implying the potential interaction between lncRNA HHIP-AS1 and HHIP mRNA. METHODS: BM-MSCs with over-expressed or silenced lncRNA HHIP-AS1 were constructed to explore the biological role of HHIP-AS1 in osteogenic differentiation. BM-MSCs were lysed to determine the alkaline phosphatase activity. Fluorescence in situ hybridization and immunofluorescence were performed to analyze HHIP-AS1, HHIP, RUNX2 and osteocalcin. RESULTS: Overexpression of lncRNA HHIP-AS1 increased HHIP expression, which suppressed Hedgehog signaling pathway, as indicated by the reduction of SMO, Gli1 and Gli2. The suppression of Hedgehog signal was associated with the inhibited osteogenesis. HHIP knockdown abolished the suppression of osteogenesis induced by lncRNA HHIP-AS1 overexpression. Through binding to HHIP mRNA, lncRNA HHIP-AS1 recruited ELAVL1 to HHIP mRNA, whereby increasing the mRNA stability and the protein level. CONCLUSIONS: This study revealed that down-regulation of HHIP due to lncRNA HHIP-AS1 reduction promoted the osteogenic differentiation of BM-MSCs though removing the suppression of Hedgehog signal.

Necroptosis of nucleus pulposus cells involved in intervertebral disc degeneration through MyD88 signaling.

Background context: Low back pain, affecting nearly 40% of adults, mainly results from intervertebral disc degeneration (IVDD), while the pathogenesis of IVDD is still not fully elucidated. Recently, some researches have revealed that necroptosis, a programmed necrosis, participated in the progression of IVDD, nevertheless, the underlying mechanism remains unclear. Purpose: To study the mechanism of necroptosis of Nucleus Pulposus (NP) cells in IVDD, focusing on the role of MyD88 signaling. Study design: The expression and co-localization of necroptotic indicators and MyD88 were examined in vivo, and MyD88 inhibitor was applied to determine the role of MyD88 signaling in necroptosis of NP cells in vitro. Methods: Human disc specimens were collected from patients receiving diskectomy for lumbar disc herniation (LDH) or traumatic lumbar fractures after MRI scanning. According to the Pfirrmann grades, they were divided into normal (Grades 1, 2) and degenerated groups (4, 5). Tissue slides were prepared for immunofluorescence to assess the co-localization of necroptotic indicators (RIP3, MLKL, p-MLKL) and MyD88 histologically. The combination of TNFα, LPS and Z-VAD-FMK was applied to induce necroptosis of NP cells. Level of ATP, reactive oxygen species (ROS), live-cell staining and electron microscope study were employed to study the role of MyD88 signaling in necroptosis of NP cells. Results: In vivo, the increased expression and co-localization of necroptotic indicators (RIP3, MLKL, p-MLKL) and MyD88 were found in NP cells of degenerated disc, while very l low fluorescence intensity in tissue of traumatic lumbar fractures. In vitro, the MyD88 inhibitor effectively rescued the necroptosis of NP cells, accompanied by increased viability, ATP level, and decreased ROS level. The effect of MyD88 inhibition on necroptosis of NP cells was further confirmed by ultrastructure of mitochondria shown by Transmission Electron Microscope (TEM). Conclusion: Our results indicated that the involvement of MyD88 signaling in the necroptosis of NP cells in IVDD, which will replenish the pathogenesis of IVDD and provide a novel potential therapeutic target for IVDD.

Exosomes derived from olfactory ensheathing cells provided neuroprotection for spinal cord injury by switching the phenotype of macrophages/microglia.

Transplantation of olfactory ensheathing cells (OECs) has been demonstrated to be beneficial for spinal cord injury (SCI) by modulating neuroinflammation, supporting neuronal survival and promoting angiogenesis. Besides OECs, the conditioned medium (CM) from OECs has also been proved to have therapeutic effects for SCI, indicating that the bioactive substances secreted by OECs are essential for its protective effects. Nevertheless, there is still little information regarding the underlying mechanisms. Considering that exosomes are crucial for intercellular communication and could be secreted by different types of cells, we speculated that the therapeutic potential of OECs for SCI might be partially based on their exosomes. To examine whether OECs could secret exosomes, we isolated exosomes by polyethylene glycol-based method, and identified them by electron microscopy study, nanoparticle tracking analysis (NTA) and western blotting. In view of phagocytic ability of microglia and its distinct roles in microenvironment regulation after SCI, we then focused the effects of OECs-derived exosomes (OECs-Exo) on microglial phenotypic regulation. We found that the extracted OECs-Exo could be engulfed by microglia and partially reverse the LPS-induced pro-inflammatory polarization through inhibiting NF-κB and c-Jun signaling pathways in vitro. Furthermore, OECs-Exo were found to inhibit the polarization of pro-inflammatory macrophages/microglia while increased the numbers of anti-inflammatory cells after SCI. Considering that the neuronal injury is closely related to the activation state of macrophages/microglia, co-culture of microglia and neurons were performed. Neuronal death induced by LPS-treated microglia could be significantly alleviated when microglia treated by LPS plus OECs-Exo in vitro. After SCI, NeuN-immunostaining and axonal tract-tracing were performed to assess neuronal survival and axon preservation. Our data showed that the OECs-Exo promoted the neuronal survival and axon preservation, and facilitated functional recovery after SCI. Our findings provide a promising therapeutic strategy for SCI based on exosome-immunomodulation.

RP11-867G2.8 promotes EMT and chordoma malignant phenotypes by enhancing FUT4 mRNA stability and translation.

Chordoma is a rare bone tumor, and the recurrence rate of chordoma is high, the treatment is difficult, and the prognosis is poor. Therefore, it is of great significance to find key target genes for the treatment of chordoma. Microarray was used to analyze the significant gene associated with chordoma. Western blot and RT-PCR were used to detect protein and mRNA expression levels of RP11-867G2.8 and FUT4. Fluorescence in situ hybridization (FISH) assay was used to locate the position of RP11-867G2.8 in chordoma cells. MTT assay, colony formation assay, transwell assay and Xenograft Mouse Model were used to clarify the function of RP11-867G2.8 and FUT4. RNA pull-down, RNA immunoprecipitation, RNA stability assay and polysome profiling analysis were used to clarify the relationship between RP11-867G2.8 and FUT4. We found that RP11-867G2.8 is highly expressed in chordoma tissues and cells, and RP11-867G2.8 overexpression promotes the malignant biological behavior of chordoma cells. RP11-867G2.8 overexpression alters the expression pattern of genes modulating signaling pathway. FUT4 is accumulated in chordoma tissues, and RP11-867G2.8 is antisense RNA of FUT4. RP11-867G2.8 can bind to FUT4 mRNA, increasing FUT4 mRNA stability and facilitating translation of FUT4. RP11-867G2.8 binds to EIF4B and PABPC1, which increases the translation of FUT4. Further studies found that FUT4 silence counteracts the effect of RP11-867G2.8 in vivo and in vitro. Our results suggest that RP11-867G2.8 promotes the development and progression of chordoma by up-regulating the expression of FUT4.

[A case-control study of minimally invasive transforaminal interbody fusion with the assistance of robot and traditional fluoroscopy in the treatment of single-space lumbar disc herniation].

OBJECTIVE: To compare the safety and nail placement accuracy of fluoroscopy-assisted and robot-assisted minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of single-space lumbar disc herniation. METHODS: The clinical data of 52 patients with single-space lumbar disc herniation treated by MIS-TLIF from March 2019 to February 2020 were retrospectively analyzed. Among them, 24 patients were treated by robot-assisted MIS-TLIF(group A) and 28 patients were treated by fluoroscopy-assisted MIS-TLIF (group B). The intraoperative blood loss, operation time, intraoperative fluoroscopy times, preoperative and postoperative visual analogue scale(VAS), Japanese Orthopaedic Association(JOA) scores and operation-related complications were recorded in two groups. Gertzbein-Robbins grade according to CT scan was used to evaluate the nail placement after operation. Grade A and B were evaluated as satisfactory nail placement, and grade C, D, and E were evaluated as error placement. Babu's method was used to evaluate the screw's invasion to the superior articular process. RESULTS: The operation time, intraoperative blood loss and intraoperative fluoroscopy times in group A were less than those in group B(P<0.05).VAS and JOA scores of all patients at the final follow-up were significantly improved compared with those before operation(P<0.05), but there was no statistically significant difference between the groups(P>0.05). There were 96 and 112 screws in group A and group B, respectively. Three days after operation, according to the Gertzbein-Robbins grade to evaluate the nail placement accuracy, there were 90 screws of grade A, 5 of grade B, 1 of grade C, no grade D and E in group A;there were 84 screws of grade A, 16 of grade B, 8 of grade C, 4 of grade D, no grade E in group B;the difference between two groups was statistically significant(Z=-3.709, P=0.000). The satisfactory rate of screw placement in group A was 98.96% (95/96), and that of group B was 89.29% (100/112), the difference between two groups was statistically significant (χ2=8.254, P=0.004). Three days after operation, the invasion of superior facet joints by pedicle screws was evaluated according to Babu's method, including 90 screws in grade 0, 4 in grade 1, 2 in grade 2, and 0 in grade 3 in group A;86 in grade 0, 12 in grade 1, 10 in grade 2 and 4 in grade 3 in group B, and the difference was statistically significant(Z=-3.433, P=0.001). There were no serious spinal cord, nerve and vascular injuries and other operation-related complications caused by screw implantation failure in both groups. All patients were followed up from 6 to 12(9.06±1.60) months. The neurological symptoms improved well after operation. During the follow-up period, there was no recurrence of symptoms, loosening or breakage of the internal fixation. CONCLUSION: Compared with the traditional fluoroscopy-assisted MIS-TLIF, the spinal robot-assisted MIS-TLIF not only has more minimally invasive and safer, but also has higher accuracy in nail placement, lower incidence of upper articular process invasion, and more accurate decompression targets, which can be used for minimally invasive treatment of single-space lumbar disc herniation.

Quercetin prevents necroptosis of oligodendrocytes by inhibiting macrophages/microglia polarization to M1 phenotype after spinal cord injury in rats.

BACKGROUND: Oligodendrocytes (OLs) death after spinal cord injury (SCI) contributes to demyelination, even leading to a permanent neurological deficit. Besides apoptosis, our previous study demonstrated that OLs underwent receptor-interacting serine-threonine kinase 3(RIP3)/mixed lineage kinase domain-like protein (MLKL)-mediated necroptosis. Considering that necroptosis is always accompanied with pro-inflammatory response and quercetin has long been used as anti-inflammatory agent, in the present study we investigated whether quercetin could inhibit necroptosis of OLs and suppress the M1 macrophages/microglia-mediated immune response after SCI as well as the possible mechanism. METHODS: In this study, we applied quercetin, an important flavonoid component of various herbs, to treat rats with SCI and rats injected with saline were employed as the control group. Locomotor functional recovery was evaluated using Basso-Beattie-Bresnahan (BBB) scoring and rump-height Index (RHI) assay. In vivo, the necroptosis, apoptosis, and regeneration of OLs were detected by immunohistochemistry, 5'-bromo-2'-deoxyuridine (BrdU) incorporation. The loss of myelin and axons after SCI were evaluated by Luxol fast blue (LFB) staining, immunohistochemistry, and electron microscopic study. The polarization of macrophages/microglia after SCI and the underlying mechanisms were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemistry. In vitro, the ATP and reactive oxygen species (ROS) level examination, propidium iodide (PI) labeling, and Western blotting were used to analyze the necroptosis of cultured OLs, while the signaling pathways-mediated polarization of cultured macrophages/microglia was detected by qRT-PCR and Western blotting. RESULTS: We demonstrated that quercetin treatment improved functional recovery in rats after SCI. We then found that quercetin significantly reduced necroptosis of OLs after SCI without influencing apoptosis and regeneration of OLs. Meanwhile, myelin loss and axon loss were also significantly reduced in quercetin-treated rats, as compared to SCI + saline control. Further, we revealed that quercetin could suppress macrophages/microglia polarized to M1 phenotype through inhibition of STAT1 and NF-κB pathway in vivo and in vitro, which contributes to the decreased necroptosis of OLs. CONCLUSIONS: Quercetin treatment alleviated necroptosis of OLs partially by inhibiting M1 macrophages/microglia polarization after SCI. Our findings suggest that necroptosis of OLs may be a potential therapeutic target for clinical SCI.

Accuracy of Robot-Assisted Percutaneous Pedicle Screw Placement for Treatment of Lumbar Spondylolisthesis: A Comparative Cohort Study.

BACKGROUND With the in-depth development of minimally invasive spine surgery in recent years, robot- and computer-assisted technologies have been increasingly used and successfully applied to spinal surgery. MATERIAL AND METHODS We performed a retrospective analysis of 60 patients with grade I or II lumbar spondylolisthesis who underwent minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) from January 2017 to December 2017. A robot-assisted surgical system was used in 30 patients for pedicle screw placement. The other 30 patients underwent fluoroscopy-guided percutaneous pedicle screw placement. RESULTS There were 130 screws placed under fluoroscopic guidance, with 26.2% penetration of the pedicle wall. There were 130 screws placed in robotic-assisted surgery, with 6.2% penetration of the pedicle wall. Severe screw deviation (Neo grade III) was identified in 4 screws in the fluoroscopy-guided group, while no severe deviation was noted in the robot-assisted group. In the fluoroscopic group, 15.6% of screws penetrated the superior articular process, and 2.1% screws had severe complications (Babu grade III). However, only 5.1% of screws in the robot-assisted group had severe complications. The mean screw insertion angle was significantly greater in the robot-assisted group than in the fluoroscopy-guided group (23.8±6.1° vs. 18.4±7.2°, P=0.017). CONCLUSIONS Compared to fluoroscopy-guided percutaneous pedicle screw placement, robot-assisted percutaneous pedicle screw placement has the following advantages: greater accuracy, lower incidences of screw penetration of the pedicle wall and invasion of the facet joints, and better screw insertion angle. Combined with MIS-TLIF, robot-assisted percutaneous pedicle screw placement is an effective minimally invasive treatment for lumbar spondylolisthesis.

Posterior surgical treatment of ankylosing spondylitis with spinal tuberculosis: A case series and long-term follow-up.

This retrospective cohort study aimed to evaluate the clinical outcomes of posterior surgical treatment of ankylosing spondylitis (AS) with spinal tuberculosis (STB). This was a retrospective study including 12 patients treated between January 2004 and April 2014 for AS with STB at our department. All patients underwent 1-stage posterior internal fixation, debridement, and bone fusion. The patients were evaluated based on the American Spinal Injury Association (ASIA), kyphotic Cobb angle, and the visual analog score (VAS). All patients were followed up for an average of 42.7 ±â€Š13.2 months after surgery and bone fusion was achieved 6.8 ±â€Š1.3 months. According to ASIA, 2 cases were rated as Grade D, 10 cases were Grade E at last follow-up. The average preoperative Cobb angle was 26.7 ±â€Š7.6° (range 15-36) and the average postoperative Cobb angle was 7.8 ±â€Š1.2° (range 6-9). The mean latest follow-up Cobb angle was 9.1 ±â€Š1.0° (range 6-10). Compared with the average preoperative Cobb angle, there were significant differences regarding the kyphotic Cobb angle measured postoperatively and at final follow-up (P < .05). The VAS significantly was considerably improved between the preoperative and the last clinical visits. These positive results demonstrate that 1-stage surgical treatment for AS with STB by posterior debridement, fusion, and instrumentation can be an effective and feasible treatment method for this specific condition. It should be noted that it is necessary to carry out antiosteoporosis treatment and perform long-segmental instrumentation in order to obtain spinal stabilization.

Accuracy of pedicle screw placement comparing robot-assisted technology and the free-hand with fluoroscopy-guided method in spine surgery: An updated meta-analysis.

BACKGROUND: A miniature spine-mounted robot has recently been introduced to further improve the accuracy of pedicle screw placement in spine surgery. However, the differences in accuracy between the robotic-assisted (RA) technique and the free-hand with fluoroscopy-guided (FH) method for pedicle screw placement are controversial. A meta-analysis was conducted to focus on this problem. METHODS: Several randomized controlled trials (RCTs) and cohort studies involving RA and FH and published before January 2017 were searched for using the Cochrane Library, Ovid, Web of Science, PubMed, and EMBASE databases. A total of 55 papers were selected. After the full-text assessment, 45 clinical trials were excluded. The final meta-analysis included 10 articles. RESULTS: The accuracy of pedicle screw placement within the RA group was significantly greater than the accuracy within the FH group (odds ratio 95%, "perfect accuracy" confidence interval: 1.38-2.07, P < .01; odds ratio 95% "clinically acceptable" Confidence Interval: 1.17-2.08, P < .01). CONCLUSIONS: There are significant differences in accuracy between RA surgery and FH surgery. It was demonstrated that the RA technique is superior to the conventional method in terms of the accuracy of pedicle screw placement.

Fixation versus Excision of Osteochondral Fractures after Patellar Dislocations in Adolescent Patients: A Retrospective Cohort Study.

BACKGROUND: Patellar dislocation is one of the most common knee injuries in the adolescent population. It is often combined with osteochondral fracture. The purpose of this study was to compare the outcomes between fixation and excision of osteochondral fractures not involving the bearing surface in adolescent patients with patellar dislocations. METHODS: Patients who underwent surgery for osteochondral fracture following patellar dislocation in our institution from 2007 to 2014 were retrospectively evaluated. Visual analog scale (VAS) of pain and the International Knee Documentation Committee (IKDC) form were used to assess knee pain and function at follow-up. Patient satisfaction was evaluated. Differences in the values of variables among groups were assessed using t-test if equal variance or Mann-Whitney U-test if not equal variance. The Pearson's Chi-square test was applied for dichotomous variables if expected frequency was >5 or Fisher's exact test was applied if not. A value of P < 0.05 was considered statistically significant. RESULTS: Forty-three patients were included, with the average age of 14.1 ± 2.3 (range, 9.0-17.0) years. Nineteen underwent fixation of osteochondral fractures and 24 did not. The average follow-up time was 28 ± 10 months. There was no significant difference in age, gender, follow-up time, causes of injury, times of dislocation, and location of osteochondral fracture between fixation and excision groups. The fixation group had a significantly longer surgery time (82 ± 14 min) and larger size of osteochondral fracture (2.30 ± 0.70 cm2) than the excision group (43 ± 10 min, 1.88 ± 0.62 cm2, respectively, t = 10.77, P < 0.01 and t = 0.84, P < 0.05). At the last follow-up, the average IKDC score in the fixation group (82.52 ± 8.71) was significantly lower than that in the excision group (89.51 ± 7.19, t = 2.65, P < 0.01). There was no significant difference in VAS of pain and patients' satisfaction. There were 7 (16%) patients with recurrent dislocation. CONCLUSION: Excision of osteochondral fractures has equivalent or better outcomes compared to fixation in adolescent patients with patellar dislocations when these fractures do not involve the bearing surface.

S1P/S1PR3 signaling mediated proliferation of pericytes via Ras/pERK pathway and CAY10444 had beneficial effects on spinal cord injury.

Pericytes have long been regarded merely to maintain structural and functional integrity of blood-brain barrier (BBB). Nevertheless, it has also been identified as a component of scar-forming stromal cells after spinal cord injury (SCI). In process of enlargement of spinal cavity after SCI, the number of pericytes increased and outnumbered astrocytes. However, the mechanism of proliferation of pericytes remains unclear. Sphingosine-1-phosphate (S1P) has been reported to play important roles in the formation of glia scar, but previous studies had paid more attention to the astrocytes. The present study aimed to observe the effects of S1P and S1P receptors (S1PRs) on proliferation of pericytes and investigate the underlying mechanism. By double immunostaining, we found that the number of PDGFRß-positive pericytes was gradually increased and sealed the cavity, which surrounded by reactive astrocytes. Moreover, the subtype of S1PR3 was found to be induced by SCI and mainly expressed on pericytes. Further, by use of CAY10444, an inhibitor of S1PR3, we showed that S1P/S1PR3 mediated the proliferation of pericytes through Ras/pERK pathway. Moreover, CAY10444 was found to have the effects of enhancing neuronal survival, alleviating glial scar formation, and improving locomotion recovery after SCI. The results suggested that S1P/S1PR3 might be a promising target for clinical therapy for SCI.

Radiological and clinical differences among three assisted technologies in pedicle screw fixation of adult degenerative scoliosis.

The purpose of this study was to compare the clinical and radiological differences among three advanced guided technologies in adult degenerative scoliosis. A total of 1012 pedicle screws were inserted in 83 patients using a spine robot (group A), 886 screws were implanted in 75 patients using a drill guide template (group B), and 1276 screws were inserted in 109 patients using CT-based navigation (group C). Screw positions were evaluated using postoperative CT scans according to the Gertzbein and Robbins classification. Other relevant data were also collected. Perfect pedicle screw insertion (Grade A) accuracy in groups A, B, and C was 91.3%, 81.3%, and 84.1%, respectively. Clinically acceptable accuracy of screw implantation (Grades A + B) respectively was 96.0%, 90.6%, and 93.0%. Statistical analysis showed the perfect and clinically acceptable accuracy in group A was significant different compared with groups B and C. Group A exhibited the lowest intra-op radiation dose and group B showed the shortest surgical time compared with the other two groups. Robotic-assisted technology demonstrated significantly higher accuracy than the drill guide template or CT-based navigation systems for difficult screw implantations in adult degenerative scoliosis and reduced the intra-op radiation dose, although it failed to reduce surgery time.

[Hydrogen sulfide stimulates the development of rat glioblastoma].

OBJECTIVE: To address the hypothesis that hydrogen sulfide (H(2)S) is a functionally significant stimulator in the development of glioblastoma (GBM) and explore the mechanism of stimulation. METHODS: Forty adult Sprague-Dawley (SD) rats were given intracerebral injection of rat C6 glioma cell suspension, and an intraperitoneal injection of sodium hydrosulfide (NaHS), an exogenous H(2)S donor. The 40 rats were randomly divided into 4 groups of 10 rats in each: the control group, NaHS group, C6 glioma group (intracerebral implantation of C6 glioma cells) and C6-NaHS group (intracerebral implantation of C6 glioma cells and intraperitoneal injection of NaHS). Food and water were freely available during all phases of the experiment. Physical symptoms were observed and the tumor size was measured. Histological changes were examined by pathology. Immunohistochemical staining was used to analyze the expression of HIF-1α and integrated optical density (IOD) was used to determine the tumor microvessel density (MVD). The H(2)S content in the brain was measured. RESULTS: The physical symptoms of tumor-bearing rats became more serious after NaHS injection. The H(2)S level in the C6 glioma group was higher than that in the control group [(35.25 ± 1.03) nmol/g vs. (29.12 ± 0.94) nmol/g, P < 0.05], and the highest H(2)S level was found in the C6-NaHS group. The pathological examination showed that the implanted tumors were predominantly spheroid with a distinct border and no capsule could be detected. Neovascular proliferation was also observed. Foci of tumor necrosis, intratumoral hemorrhage, pseudopalisades and tumor cavity were clearly observed. The glioma cells had scant eosinophilic cytoplasm and enlarged hyperchromatic nuclei. All these phenomena were more markedly in the C6-NaHS group compared with that in other three groups. The mean tumor volume was significantly different between the C6 and C6-NaHS rats [(32.0 ± 6.9) mm(3) vs. (67.8 ± 11.9) mm(3), P < 0.001]. Immunohistochemical analysis exhibited that the hypoxia-inducible factor-1alpha (HIF-1α) and CD34 expression were significantly increased after the intraperitoneal injection of NaHS in the C6-NaHS rats (comparing the IOD between C6-NaHS group and C6 group, HIF-1α: 133 962.9 ± 451.4 vs. 38 569.8 ± 408.6, P < 0.001; CD34: 73 368.6 ± 404.8 vs. 14 570.6 ± 748.7, P < 0.001). Moreover, compared with the C6 group, there were higher MVD in the C6-NaHS group [(41.2 ± 7.9)/mm(2) vs. (97.0 ± 10.8)/mm(2), P < 0.001]. CONCLUSIONS: H(2)S serves as a stimulator in the development of rat glioblastoma and exogenous H(2)S strongly promotes the tumor growth. The stimulating mechanisms include the increase of HIF-1α expression and neovascular formation. H(2)S may be a significant regulator in the development of tumor.

Induction of apoptosis by melamine in differentiated PC12 cells.

Melamine (2, 4, 6-triamino-1, 3, 5-triazine) was found in milk powder as an additive to raise the measured protein content in 2008 and thereby resulted in the outbreak of renal failure in infants in China. Previous studies focused on the renal toxicity in dogs and in cats. However, the toxicity of melamine in the central nervous system (CNS) is of little concern. The purpose of this study was to assess the possibility of melamine toxicity in differentiated PC12 cells. MTT assay indicated that melamine (above 33 µg/ml and 12 h) inhibited the proliferation of differentiated PC12 cells in a concentration- and time-dependent manner. Hoechst 33258 staining and flow cytometry assay showed that melamine induced the apoptotic cell death rather than necrosis in a dose-dependent manner. Reduced superoxide dismutase activity indirectly indicated that melamine could cause oxidative damage in differentiated PC12 cells. These results suggest that melamine is able to cause cytotoxicity in differentiated PC12 cells with involvement of oxidative damage and will provide evidence for further research on the potential toxicity in CNS.

Impaired hippocampal synaptic plasticity in C6 glioma-bearing rats.

For many glioblastoma multiforme patients, cognitive deficits are part of the disease process. In this study we attempted to determine the role of synaptic plasticity and glutamate (Glu) in C6 glioma-bearing rats. Male Sprague-Dawley (SD) rats were subjected to tumor implantation in the right caudate putamen nucleus. At 17 days after tumor implantation, animals were exposed to an open field test. The numbers of crossings and rearings were used as measures of exploration processes. An input/output (I/O) curve was first determined using the measurements of field excitatory postsynaptic potential (fEPSP) slope in response to a series of stimulation intensities. The short-term potentiation (STP) and long-term potentiation (LTP) induced by high-frequency stimulation (HFS) in the CA1 region of the contralateral hippocampus to the tumor were recorded. The glutamate and γ-aminobutyric acid (GABA) content of contralateral hippocampus were quantified by high-performance liquid chromatography (HPLC). C6 glioma-bearing rats showed a trend for a rightward shift of input/output relationship and significant deficits in maintenance of STP and LTP. Quantitative analysis by HPLC of glutamate and γ-aminobutyric acid revealed that Glu concentration and Glu/GABA ratio were increased significantly in contralateral hippocampus, suggesting impairment of excitatory and inhibitory synaptic transmission. The results suggest that the neurocognitive deficits in C6 glioma-bearing rats may be mediated via profound changes in neuroplasticity and elevated Glu concentration and Glu/GABA ratio in hippocampus area of the brain.