Etomidate affects the anti-oxidant pathway to protect retinal ganglion cells after optic nerve transection.

Our previous studies revealed that etomidate, a non-barbiturate intravenous anesthetic agent, has protective effects on retinal ganglion cells within 7 days after optic nerve transection. Whether this process is related to anti-oxidative stress is not clear. To reveal its mechanism, we established the optic nerve transection injury model by transecting 1 mm behind the left eyeball of adult male Sprague-Dawley rats. The rats received an intraperitoneal injection of etomidate (4 mg/kg) once per day for 7 days. The results showed that etomidate significantly enhanced the number of retinal ganglion cells retrogradely labeled with Fluorogold at 7 days after optic nerve transection. Etomidate also significantly reduced the levels of nitric oxide and malonaldehyde in the retina and increased the level of glutathione at 12 hours after optic nerve transection. Thus, etomidate can protect retinal ganglion cells after optic nerve transection in adult rats by activating an anti-oxidative stress response. The study was approved by the Animal Ethics Committee at Air Force Medical University, China (approval No. 20180305) on March 5, 2018.

Moderate prenatal alcohol exposure suppresses the TLR4-mediated innate immune response in the hippocampus of young rats.

Prenatal alcohol exposure (PAE) could lead to developmental disorders of the central nervous system (CNS) and mental retardation. Toll-like receptor (TLR) 4 plays an important role in PAE-induced neurodevelopmental defects. However, how PAE affects TLR4 response in the brain remains controversial. Using a moderate PAE model by feeding pregnant rats with liquid ethanol diet, we investigated the TLR4-mediated response to intraventricular injection of lipopolysaccharide (LPS) in the hippocampus of PEA rats at postnatal day (PND) 30. The results showed that PAE significantly up-regulated the expression of Toll-Interleukin-1 Receptor (TIR)-domain-containing adaptor protein inducing interferon (IFN)-ß (TRIF), TNF-α, and IL-1ß in the rat hippocampus in the absence of LPS, indicated by western blot assay. LPS treatment dramatically up-regulated the expressions of TLR4 and its downstream molecules in the hippocampus of paired-food and control groups. But no such significant changes of those molecules were found in the hippocampus of PAE animals. Moreover, the LPS stimulation even down-regulated the levels of TLR4 and TRIF in the PAE group. These data suggest that the relatively moderate level of PAE may lead to a mild neuroinflammation and a suppression of TLR4-mediated response to LPS in the hippocampus of young rats. As innate immunity plays crucial roles in CNS development, moderate PAE-induced suppression of TLR4-mediated response may serve as a new candidate mechanism of CNS developmental defects.

Branched-Chain Amino Acids Enhance Retinal Ganglion Cell Survival and Axon Regeneration after Optic Nerve Transection in Rats.

PURPOSE: This study's aim was to investigate the beneficial effects of branched-chain amino acids (BCAAs) on the neuronal survival and axon regeneration of retinal ganglion cells (RGCs) after optic nerve (ON) transection. METHOD: The experimental rats received daily BCAA injections through the caudal vein after left intra-orbital ON transection. Neuroprotection was evaluated by counting Fluorogold-labeled RGCs. The role of mammalian target of rapamycin (mTOR) pathway activation in promoting RGC survival was studied after rapamycin administration. Moreover, a peripheral nerve (PN) graft was transplanted onto the transected ON to study the effects of BCAAs on axon regeneration of injured RGCs. RESULTS: Our results showed that BCAAs alleviated the death of RGCs 7 and 14 days after ON transection, accompanied by an activation of mTOR pathway in RGCs. Blocking mTOR pathway with rapamycin eliminated such neuroprotective effects of BCAAs. Moreover, BCAAs also promoted axon regeneration of injured RGCs into a PN graft. CONCLUSION: Our results suggest a neuroprotection of BCAAs through the activation of mTOR pathway. BCAAs also have a beneficial effect on axon regeneration of injured RGCs. Therefore, BCAAs could be considered for the clinical treatment of ON injury.

Photoluminescence properties and thermal stability of blue-emitting Ba5-xCl(PO4)3:xEu2+ (0.004≤x≤0.016) phosphors.

A series of blue-emitting Ba5-xCl(PO4)3:xEu2+ (0.004≤x≤0.016) phosphors were synthesized by conventional high-temperature solid state reaction. The structure and photoluminescence (PL) properties of the phosphors were investigated. The as-prepared phosphors exhibit broad excitation band ranging from 250 to 420nm, and strong asymmetric blue emission band peaking at 436nm. The optimum concentration of Eu2+ in the Ba5Cl(PO4)3:Eu2+ phosphor is x=0.01, and the concentration quenching mechanism is verified to be the combined actions of dipole-dipole interaction and radiation re-absorption mechanism. The thermal stability of Ba5Cl(PO4)3:Eu2+ was evaluated by temperature-dependent PL spectra. Compared with that of commercial BaMgAl10O17:Eu2+ (BAM) phosphor, the Ba5-xCl(PO4)3:xEu2+ phosphors exhibit similarly excellent thermal quenching property. In addition, the CIE chromaticity coordinates of Ba5-xCl(PO4)3:xEu2+ (0.004≤x≤0.016) were calculated to evaluate the color quality. All the results indicate that Ba5Cl(PO4)3:Eu2+ is a promising candidate phosphor for near-ultraviolet (n-UV) pumped LED.

Dose-dependent protective effect of lithium chloride on retinal ganglion cells is interrelated with an upregulated intraretinal BDNF after optic nerve transection in adult rats.

Neuroprotection of lithium for axotomized retinal ganglion cells (RGCs) is attributed to upregulated intraretinal Bcl-2. As lithium also upregulates brain-derived neurotrophic factor (BDNF) which can rescue axotomized RGCs, it is hypothesized that lithium could protect RGCs through BDNF. This study investigated this hypothesis and a possible relationship between the dose and protection of lithium. All adult experimental rats received daily intraperitoneal injections of lithium chloride (LiCl) at 30, 60 or 85 mg/kg·bw until they were euthanized 2, 7 or 14 days after left intraorbital optic nerve (ON) transection. Our results revealed that RGC densities promoted and declined with increased dose of LiCl and the highest RGC densities were always in the 60 mg/kg·bw LiCl group at both 7 and 14 day points. Similar promotion and decline in the mRNA and protein levels of intraretinal BDNF were also found at the 14 day point, while such BDNF levels increased in the 30 mg/kg·bw LiCl group but peaked in the 60 and 85 mg/kg·bw LiCl groups at the 7 day point. These findings suggested that lithium can delay the death of axotomized RGCs in a dose-dependent manner within a certain period after ON injury and such beneficial effect is interrelated with an upregulated level of intraretinal BDNF.

Phagocytic removal of neuronal debris by olfactory ensheathing cells enhances neuronal survival and neurite outgrowth via p38MAPK activity.

Compelling evidence from animal models and clinical studies suggest that transplantation of olfactory ensheathing cells (OECs), specialized glia in the olfactory system, combined with specific training may be therapeutically useful in the central nervous system (CNS) injuries and neurodegenerative diseases. The unique function of OECs could mainly attribute to both production of cell adhesion molecules and secretion of growth factors in OECs, which support neuron survival and neurite outgrowth. However, little is known about whether engulfment of neuronal degenerative debris by OECs also equally contributes to neuronal survival and neurite outgrowth. Furthermore, the molecular mechanisms responsible for neuronal degenerative corpses' removal remain elusive. Here, we used an in vitro model of primary culture of spinal cord neurons to investigate the effect of engulfment of degenerative neuron debris by OECs on neuronal survival and neurite outgrowth and the possible molecular mechanisms. Our results showed that OECs can engulf an amount of degenerated neuron debris, and this phagocytosis can make a substantial contribution to neuron growth, as demonstrated by increased number of neurons with longer neurite length and richer neurite branches when compared with the combination of neuron debris and OEC conditioned medium (OECCM). Moreover, p38 mitogen-activated protein kinase (p38MAPK) signaling pathway may mediate the OEC engulfment of debris because the p38MAPK-specific inhibitor, SB203580, can abrogate all the positive effects of OECs, including clearance of degenerated neuron debris and generation of bioactive molecules, indicating that p38MAPK is required for the process of phagocytosis of the neuron debris. In addition, the OEC phagocytic activity had no influence on its generation of bioactive molecules. Therefore, these findings provide new insight into further investigations on the OEC role in the repair of traumatic CNS injury and neurodegenerative diseases.

Different neuroprotection and therapeutic time windows by two specific diazepam regimens on retinal ganglion cells after optic nerve transection in adult rats.

PURPOSE: To compare neuroprotection and therapeutic time windows of two diazepam regimens on retinal ganglion cells (RGCs) after rat optic nerve transection (ONT). METHODS: Adult rats received initial intraperitoneal diazepam injections 30 minutes before left ONT, followed by daily diazepam (regimen-A) or every 8 hours for 3 days (regimen-B) until they were killed at day 7 or 14. Initial diazepam in regimen-A and regimen-B was delayed to 3, 6, 7, 9, 10, 12 and 6, 7, 8, 9, 10, 12 hours after ONT and these animals survived for 7 days. The effect of daily combinational uses of diazepam and bicuculline was assayed at 7 days. RESULTS: Regimen-A induced higher RGC densities than those in control and regimen-B groups at day 7, but lower density than regimen-B did at day 14. When initial diazepam was delayed beyond 6 or 8 hours after ONT with regimen-A and regimen-B, the promoting effects of diazepam on RGC densities disappeared. Bicuculline completely inhibited the protection of diazepam. CONCLUSIONS: Prolonged neuroprotection on RGCs at day 14 and extended therapeutic time window for 8 hours can be achieved by regimen-B, while regimen-A induces a stronger neuroprotection at day 7. Diazepam neuroprotection is mediated through GABAA receptor.

BLCAP induces apoptosis in human Ewing's sarcoma cells.

Bladder cancer-associated protein (BLCAP) is a novel candidate tumor suppressor gene identified from human bladder carcinoma and highly associated with the invasion of bladder cancer. We previously reported that it also plays a key role in the tumorigenesis and metastasis of human osteosarcoma. In the present study, we constructed a recombinant encoding BLCAP cDNA. Overexpression of BLCAP resulted in growth inhibition and induced apoptosis of human TC-135 Ewing's sarcoma cells in vitro. We further investigated the caspase-3/7 activity and expressions of the fusion transcription factor Ewing's sarcoma protein-friend leukemia virus integration 1 (EWS-FLI1) and the apoptosis regulator B-cell lymphoma 2 (BCL-2). Cell apoptosis was accompanied by the down-regulated expression of EWS-FLI1 and BCL-2. Our present results suggest that BLCAP may play a role not only in regulating cell proliferation but also in coordinating apoptosis through the down-regulation of BCL-2 and EWS-FLI1 in human Ewing's sarcoma cells.

Five new diarylpropan-1-ols from Combretum yunnanense.

Five new 1,3-diarylpropan-1-ols, combretol A-E (1- 5), together with one known coumarin (6) and ten known triterpenes (7-16), were isolated from Combretum yunnanense. Their structures were determined by spectroscopic investigation, including ¹H and ¹³C NMR, NOESY, HSQC, HMBC, and HRESIMS analyses. This is the first report on the occurrence of 1,3-diarylpropan-1-ols and coumarin in the Combretum genus including C. yunnanense. Also, to the best of our knowledge, 1,3-diarylpropan-1-ols are rare in nature.

Glycomimetic improves recovery after femoral injury in a non-human primate.

In adult mammals, restoration of function after peripheral nerve injury is often poor and effective therapies are not available. Previously we have shown in mice that a peptide which functionally mimics the human natural killer cell (HNK)-1 trisaccharide epitope significantly improves the outcome of femoral nerve injury. Here we evaluated the translational potential of this treatment using primates. We applied a linear HNK-1 mimetic or a functionally inactive control peptide in silicone cuffs used to reconstruct the cut femoral nerves of adult cynomolgus monkeys (Macaca fascicularis). Functional recovery was evaluated using video-based gait analysis over a 160-day observation period. The final outcome was further assessed using force measurements, H-reflex recordings, nerve histology, and ELISA to assess immunoreactivity to HNK-1 in the treated monkeys. Gait deficits were significantly reduced in HNK-1 mimetic-treated compared with control peptide-treated animals between 60 and 160 days after injury. Better outcome at 160 days after surgery in treated versus control animals was also confirmed by improved quadriceps muscle force, enhanced H-reflex amplitude, decreased H-reflex latency, and larger diameters of regenerated axons. No adverse reactions to the mimetic, in particular immune responses resulting in antibodies against the HNK-1 mimetic or immune cell infiltration into the damaged nerve, were observed. These results indicate the potential of the HNK-1 mimetic as an efficient, feasible, and safe adjunct treatment for nerve injuries requiring surgical repair in clinical settings.

New chalcone and dimeric chalcones with 1,4-p-benzoquinone residue from Combretum yunnanense.

New chalcone and dimeric chalcones with 1,4- P-benzoquinone residue, combrequinone A (1), combrequinone B (2), and combrequinone C (3), along with three known compounds (4-6), were isolated from the ethanolic extract of the stems and leaves of Combretum yunnanense, and their structures were determined by spectroscopic analysis. Compounds 1-3 were evaluated for in vitro cytotoxicity against five human cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7, and SW480. Compounds 1, 2 and 3 were found to be most potent against HL-60 acute leukemia cells, with IC50 values of 4.63, 4.07, and 1.26 µM, respectively.

Neutralization of BDNF attenuates the in vitro protective effects of olfactory ensheathing cell-conditioned medium on scratch-insulted retinal ganglion cells.

Transplantation of olfactory ensheathing cells (OECs) becomes one of the promising strategies in restoring lost functions of injured central nervous system. Elevated level of expressed brain-derived neurotrophic factor (BDNF) was revealed in the previous studies to be related to the protective effects of OECs on injured cortical and brain stem neurons as well as retinal ganglion cells (RGCs), but no evidence has been obtained to demonstrate whether transplanted OECs protect injured central neurons directly by their secreted BDNF. In the present study, the effects of BDNF neutralization on the neuroprotection of adult OEC-conditioned medium (OEC-CM) on scratch-insulted RGCs were examined. The results showed that OEC-CM protected cultured RGCs from scratch insult, and neutralization of BDNF by BDNF neutralizing antibody attenuated such neuroprotection of the medium. It is thus concluded that neurotrophic factors including BDNF secreted by OECs can protect injured OECs in vitro and BDNF plays a major role in such a protection of OECs.

Death of axotomized retinal ganglion cells delayed after intraoptic nerve transplantation of olfactory ensheathing cells in adult rats.

Intraorbital transection of the optic nerve (ON) always induces ultimate apoptosis of retinal ganglion cells (RGCs) and consequently irreversible defects of vision function. It was demonstrated that transplanted olfactory ensheathing cells (OECs) in partially injured spinal cord have a distant in vivo neuroprotective effect on descending cortical and brain stem neurons. However, this study gave no answers to the question whether OECs can protect the central sensitive neurons with a closer axonal injury because different neurons respond variously to similar axonal injury and the distance between the neuronal soma and axonal injury site has a definite effect on the severity of neuronal response and apoptosis. In the present study, we investigated the effect of transplanted OECs on RGCs after intraorbital ON transection in adult rats. Green fluorescent protein (GFP)-OECs were injected into the ocular stumps of transected ON and a significantly higher number of surviving RGCs was found together with a consistent marked increase in the mRNA and protein levels of BDNF in the ON stump and retina in the OEC-treated group at 7 days, but not 2 and 14 days, time point when compared to the control group. Our findings suggest that OEC transplantation induces the expression of BDNF in the ocular ON stump and retina and delays the death of axotomized RGCs at a certain survival period.

Silencing of calpain expression reduces the metastatic potential of human osteosarcoma cells.

Osteosarcoma, the most common primary bone tumor in young adults, is characterized by local invasion and distant metastasis. But detailed mechanisms of tumorigenicity and metastasis of osteosarcoma are not well known. We report the involvement of calpains, a family of calcium-activated, cysteine proteases, in the invasive and metastatic processes of human osteosarcoma cells. By using siRNA treatment, the expression of mu- and m-calpains were downregulated in human Saos-2 osteosarcoma cells. Both the adhesive and invasive potentials were significantly attenuated in calpain siRNA-transfected human Saos-2 osteosarcoma cells. MMPs are the main factors involved in malignant tumor invasion and metastasis. siRNA of calpains also significantly inhibited the secretion of MMP-2 in Saos-2 cells. These results suggest that mu- and m-calpains are important in the invasion and metastasis of human osteosarcoma cells, and calpains might be targeted to reduce tumor progression.

Neuroprotective effect of inosine on axotomized retinal ganglion cells in adult rats.

PURPOSE: To explore the potential survival-promoting effect of inosine on axotomized retinal ganglion cells (RGCs) of adult rats in vivo. METHODS: The left optic nerves (ON) in the subject rats were transected at 1.5 mm from the optic disc. Repeated intraperitoneal injections or single intraocular injection of inosine were administered. The RGCs were retrogradely labeled with a gold fluorescent dye and the density of surviving RGCs in number per square millimeter of retina was calculated in wholemounted retinas. The functional integrity of the blood-retinal barrier (BRB) after ON transection was evaluated with an intravenous injection of Evans blue. RESULTS: In control animals, the mean density of surviving RGCs (number per square millimeter) of the whole retina was 2007 +/- 68 at 2 days (taken as the normal value), 927 +/- 156 at 7 days, and 384 +/- 33 at 14 days after surgery. Repeated intraperitoneal injections (75 mg/kg for each injection) of inosine significantly enhanced RGC survival at 14 days after ON transection (500 +/- 38), whereas no significant difference in the densities was detected at 7 days (974 +/- 101), even when the dosage of inosine was doubled (1039 +/- 61). At this time point, however, a single intraocular injection of inosine significantly increased the density of surviving RGCs (1184 +/- 156). Moreover, more RGCs around the optic disc were rescued when inosine, administered either intraperitoneally or intraocularly, showed a beneficial effect on RGC survival. No breakdown of the BRB after ON transection was detected with the method used in the study. CONCLUSIONS: These findings demonstrate that inosine could protect axotomized RGCs in vivo after ON transection.

Effects of inosine on axonal regeneration of axotomized retinal ganglion cells in adult rats.

Damage to the central nervous system (CNS) is always followed by an irreversible axon degeneration of injured neurons. The purine nucleoside inosine has been shown to induce neurons to regenerate axons in culture and in vivo. In the present study, we investigated the in vivo effects of inosine on the axon regeneration of axotomized retinal ganglion cells (RGCs) in adult rats, using the model of peripheral nerve (PN) grafting onto the ocular stump of the transected optic nerve. Animals were allowed to survive for 4 weeks after surgery with repeated intraperitoneal injections of inosine 1 day before PN grafting till they were killed. Treatment with inosine induced a significant increase (62%) in the number of FluroGold -labeled RGCs regrowing their axons into the PN graft, when compared with the control animals. The axon outgrowth-promoting effect of inosine in adult rodents may represent a potential clinical treatment for injured or degenerated CNS.