Is air pollution detrimental to regional innovation? An empirical heterogeneity test based on Chinese cities.

Nowadays, innovation seems to be the inevitable choice to achieve stable economic growth. However, the negative impact of air pollution on health and economy makes air pollution an important factor in regional innovation, which deserves our discussion. The overall regional innovation level from 2014 to 2019 has an upward trend, while the overall air pollution has a downward trend during the period, which provides foundation for our research. Based on the data of 285 prefecture-level cities in China from 2014 to 2019, this paper uses the fixed effect and mediation model to verify the impact and mechanism of air pollution on regional innovation. The results show that the increase in air pollution, measured by the air quality index, significantly inhibits regional innovation. Air pollution has significant funds crowding-out effect and human capital loss effect, thereby decreasing the regional innovation level, which means innovation funds and researchers play a conductive role between air pollution and regional innovation. In heterogeneity analysis, it is found that the detrimental effect of air pollution on regional innovation is significant in eastern and central China, in large- and medium-sized cities, and in cities with poor or general air quality. It indicates that developed and large-scale regions should pay more attention to air pollution control. For polluted regions, more emphasis and endeavors are needed to address air pollution problems. Besides, the inhibitory effect is more severe on incremental innovation rather than on radical innovation, which deserves the attention of enterprises engaged in incremental innovation. Therefore, we propose that targeted environmental policies and effective measures should be developed to improve air quality in the long run. Moreover, policymakers could provide strong support for innovation grants, talent subsidies, and rewards and encourage clean technological innovation through short-term trade-offs between heavily polluting and low polluting enterprises.

Sulforaphane protects against skeletal muscle dysfunction in spontaneous type 2 diabetic db/db mice.

AIMS: Skeletal muscle diseases have become to be the most common complication in patients with type 2 diabetic mellitus (T2DM). However, the effective therapies against skeletal muscle diseases are not yet available. Sulforaphane (SFN) is an organic isothiocyanate found in cruciferous plants. Our aim was to explore whether SFN could attenuate the skeletal muscle diseases in spontaneous type 2 diabetic db/db mice. MATERIALS AND METHODS: The db/m and littermate db/db mice were treated with SFN or dimethyl sulfoxide. The grip strength of mice was measured by a grasping forcing machine. The electron transmission microscopy was used to perform the skeletal muscle. The western blot was used to detect the nuclear factor E2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) signal pathway related proteins, and inflammatory and apoptotic associated proteins. The mRNA levels of anti-inflammatory and anti-oxidative relative genes were detected by RT-QPCR. KEY FINDINGS: We found that SFN could significantly increase the grip strength of the db/db mice. The lean mass and gastrocnemius mass were increased in the db/db mice after administration with SFN. Additionally, the db/db mice restored the skeletal muscle fiber organization after SFN treatment. Mechanistically, SFN could activate the Nrf2/HO-1 signal pathway, and downregulate the expression of inflammatory and apoptotic associated proteins. Furthermore, SFN could also regulate the mRNA levels of anti-inflammatory and anti-oxidative related genes. SIGNIFICANCE: Our results demonstrated that SFN can protect against skeletal muscle diseases in db/db type 2 diabetic mice and provide a potential drug to prevent skeletal muscle dysfunction in T2DM patients.

Post-Traumatic Epilepsy and Seizure Susceptibility in Rat Models of Penetrating and Closed-Head Brain Injury.

Traumatic brain injury (TBI) carries a risk of developing post-traumatic epilepsy (PTE). Currently, animal models that replicate clinical PTE (delayed spontaneous and recurrent seizures) are limited, which hinders pre-clinical research. In this study, we used two rat models of penetrating ballistic-like brain injury (PBBI) and closed-head injury (CHI) to induce spontaneous seizures and also measure changes in seizure susceptibility. In the PBBI model, two trajectories (frontal and lateral) and two injury severities for each trajectory, were evaluated. In the CHI model, a single projectile impact to the dorsal/lateral region of the head was tested. Continuous video-electroencephalographic (EEG) recordings were collected for 10 days at 1 or 6 month(s) post-injury. After EEG recording, all rats were given a sub-convulsant dose of pentylenetetrazole (PTZ) to challenge the seizure susceptibility. The video-EEG recording did not detect PTE following the PBBI. Only one CHI rat demonstrated persistent and recurrent non-convulsive seizures detected at 6 months post-injury. However, after PTZ challenge, 50-100% of the animals across different TBI groups experienced seizures. Seizure susceptibility increased over time from 1 to 6 months post-injury across the majority of TBI groups. Injury severity effects were not apparent within the PBBI model, but were evident between PBBI and CHI models. These results demonstrated the difficulties in detecting delayed spontaneous post-traumatic seizures even in a high-risk model of penetrating brain injury. The PTZ-induced increase in seizure susceptibility indicated the existence of vulnerable risk of epileptogenesis following TBI, which may be considered as an alternative research tool for pre-clinical studies of PTE.

Combination therapy of levetiracetam and gabapentin against nonconvulsive seizures induced by penetrating traumatic brain injury.

BACKGROUND: Posttraumatic seizures are a medical problem affecting patients with traumatic brain injury. Yet effective treatment is lacking owing to the limitations of antiepileptic drugs (AEDs) applicable to these patients. METHODS: In this study, we evaluated the dose-response efficacy of levetiracetam (12.5-100.0 mg/kg) and gabapentin (1.25-25.0 mg/kg) administered either individually or in pairs at fixed-dose ratios as a combination in mitigating posttraumatic nonconvulsive seizures induced by severe penetrating ballistic-like brain injury (PBBI) in rats. Seizures were detected by continuous electroencephalogram (EEG) monitoring for 72 hours postinjury. Animals were treated twice per day for 3 days by intravenous injections. RESULTS: Both levetiracetam (25-100 mg/kg) and gabapentin (6.25-25 mg/kg) significantly reduced PBBI-induced seizure frequency by 44% to 73% and 61% to 69%, and seizure duration by 45% to 64% and 70% to 78%, respectively. However, the two drugs manifested different dose-response profiles. Levetiracetam attenuated seizure activity in a dose-dependent fashion, whereas the beneficial effects of gabapentin plateaued across the three highest doses tested. Combined administration of levetiracetam and gabapentin mirrored the more classic dose-response profile of levetiracetam monotherapy. However, no additional benefit was derived from the addition of gabapentin. Furthermore, isobolographic analysis of the combination dose-response profile of levetiracetam and gabapentin failed to reach the expected level of additivity, suggesting an unlikelihood of favorable interactions between these two drugs against spontaneously occurring posttraumatic seizure activities at the particular set of dose ratios tested. CONCLUSION: This study was the first attempt to apply isobolographic approach to studying AED combination therapy in the context of spontaneously occurring posttraumatic seizures. Despite the failure to achieve additivity from levetiracetam and gabapentin combination, it is important to recognize the objectivity of the isobolographic approach in the evaluation of AED combination therapy against seizures directly associated with brain injuries.

Nefiracetam attenuates post-ischemic nonconvulsive seizures in rats and protects neuronal cell death induced by veratridine and glutamate.

AIMS: Stroke patients are at a high risk of developing post-ischemic seizures and cognitive impairment. Nefiracetam (NEF), a pyrrolidone derivative, has been shown to possess both anti-epileptic and cognitive-enhancing properties. In this study the anti-seizure effects of NEF were evaluated in a rat model of post-ischemic nonconvulsive seizures (NCSs). Its potential mechanisms were investigated in neuronal cell culture assays of neurotoxicity associated with ischemic brain injury and epileptogenesis. MAIN METHODS: In the in vivo study, rats received 24h permanent middle cerebral artery occlusion. NEF was administered intravenously either at 15 min post-injury but prior to the first NCS event (30 mg/kg, pre-NCS treatment) or immediately after the first NCS occurred (30 or 60 mg/kg, post-NCS treatment). In the in vitro study, neuronal cell cultures were exposed to veratridine or glutamate and treated with NEF (1-500 nM). KEY FINDINGS: The NEF pre-NCS treatment significantly reduced the NCS frequency and duration, whereas the higher NEF dose (60 mg/kg) was required to achieve similar effects when given after NCS occurred. The NEF treatment also dose-dependently (5-500 nM) protected against neuronal cell death induced by veratridine as measured by MTT cell viability assay, but higher doses (250-500 nM) were required against glutamate toxicity. SIGNIFICANCE: The anti-seizure property of NEF was demonstrated in a clinically relevant rat model of post-ischemic NCS. The preferential effects of NEF against in vitro veratridine toxicity suggest the involvement of its modulation of sodium channel malfunction. Future studies are warranted to study the mechanisms of NEF against ischemic brain injury and post-ischemic seizures.

Long-term administration of amnion-derived cellular cytokine suspension promotes functional recovery in a model of penetrating ballistic-like brain injury.

BACKGROUND: Previous work has shown that human amnion-derived progenitor (AMP) cell therapy is neuroprotective in a penetrating ballistic-like brain injury (PBBI) model. However, the neuroprotective capacity of AMP cells seemed to be mediated by the sustained secretion of AMP cell-derived neurotrophic factors, which are abundant in the amnion-derived cellular cytokine suspension (ACCS). To test this theory, the current study assessed the neuroprotective efficacy of long-term ACCS delivery in the PBBI model. METHODS: Experiment 1 assessed the bioactive stability and neuroprotective capacity of ACCS in an in vitro model of neurodegeneration. Experiment 2 evaluated the therapeutic effects of ACCS delivery initiated 15 minutes after PBBI and continued for 2 weeks after injury. Experiment 3 was designed to identify the therapeutic window for long-term ACCS delivery in the PBBI model. Outcome metrics included neurobehavioral assessments and neuropathologic measures of neuroinflammation and axonal/neuronal degeneration. RESULTS: Experiment 1 demonstrated that ACCS is thermally stable for 1 week at 37°C and that ACCS treatment protected neurite against staurosporine toxicity. Experiment 2 identified the optimal infusion rate of ACCS (1 µL/h) and demonstrated that long-term infusion of ACCS was capable of promoting significant protection against PBBI-induced neuropathology and motor abnormalities, but was not sufficient for reducing cognitive deficits. Finally, the results of Experiment 3 showed that ACCS is effective in promoting significant neuroprotection even when onset of treatment is delayed out to 24 hours (but not 48 hours) after PBBI. CONCLUSIONS: Collectively, our results support the hypothesis that the neuroprotective effects of AMP cells are mediated through a sustained delivery of ACCS, which implicates ACCS as a promising neuroprotection agent for clinical study.

A novel animal model of closed-head concussive-induced mild traumatic brain injury: development, implementation, and characterization.

Closed-head concussive injury is one of the most common causes of traumatic brain injury (TBI). While single concussions result in short-term neurologic dysfunction, multiple concussions can result in cumulative damage and increased risk for neurodegenerative disease. Despite the prevalence of concussion, knowledge about what occurs in the brain following this injury is limited, in part due to the limited number of appropriate animal research models. To study clinically relevant concussion we recently developed a simple, non-invasive rodent model of closed-head projectile concussive impact (PCI) TBI. For this purpose, anesthetized rats were placed on a platform positioned above a torque-sealed microcentrifuge tube packed with fixed amounts of dry ice. Upon heating, rapid sublimation of the dry ice produced a build-up of compressed CO(2) that triggered an eruptive force causing the cap to launch as an intact projectile, resulting in a targeted PCI head injury. A stainless steel helmet was implemented to protect the head from bruising, yet allowing the brain to sustain a mild PCI event. Depending on the injury location and the application of the helmet, PCI-induced injuries ranged from severe (i.e., head injury with subdural hematomas, intracranial hemorrhage, and brain tissue damage), to mild (no head injury, intracranial hemorrhage, or gross morphological pathology). Although no gross pathology was evident in mild PCI-induced injury, the following protein changes and behavioral abnormalities were detected between 1 and 24 h after PCI injury: (1) upregulation of glial fibrillary acidic protein (GFAP) in hippocampal regions; (2) upregulation of ubiquitin carboxyl-terminal hydrolase L1 (UCHL-1) in cortical tissue; and (3) significant sensorimotor abnormalities. Overall, these results indicated that this PCI model was capable of replicating salient pathologies of a clinical concussion, and could generate reproducible and quantifiable outcome measures.

The biological activity of ubiquitinated BoNT/B light chain in vitro and in human SHSY-5Y neuronal cells.

BoNT/B light chain is a zinc-dependent endopeptidase. After entering its target, the neuronal cell, BoNT/B is responsible for synaptobrevin-2 (VAMP-2) cleavage. This results in reduced neurotransmitter (acetylcholine) release from synaptic vesicles, yielding muscular paralysis. Since the toxin persists in neuronal cells for an extended period, regeneration of VAMP-2 is prevented. We evaluated therapeutic targets to overcome botulinum persistence because early removal would rescue the neuronal cell. The ubiquitination/proteasome cellular pathway is responsible for removing "old" or undesirable proteins. Therefore, we assessed ubiquitination of BoNT/B light chain in vitro, and characterized the effects of ubiquitination modulating drugs, PMA (phorbol 12-myristate 13-acetate) and expoxomicin, on ubiquitination of BoNT/B light chain in neuronal cells. Both drugs altered BoNT/B light chain ubiquitination. Ubiquitination in vitro and in cells decreased the biological activity of BoNT/B light chain. These results further elucidate BoNT protein degradation pathways in intoxicated neuronal cells and mechanisms to enhance toxin removal.

NNZ-2566, a glypromate analog, improves functional recovery and attenuates apoptosis and inflammation in a rat model of penetrating ballistic-type brain injury.

Glycine-proline-glutamate (GPE) is an N-terminal tripeptide endogenously cleaved from insulin-like growth factor-1 in the brain and is neuroprotective against hypoxic-ischemic brain injury and neurodegeneration. NNZ-2566 is an analog of GPE designed to have improved bioavailability. In this study, we tested NNZ-2566 in a rat model of penetrating ballistic-type brain injury (PBBI) and assessed its effects on injury-induced histopathology, behavioral deficits, and molecular and cellular events associated with inflammation and apoptosis. In the initial dose-response experiments, NNZ-2566 (0.01-3 mg/kg/h x 12 h intravenous infusion) was given at 30 min post-injury and the therapeutic time window was established by delaying treatments 2-4 h post-injury, but with the addition of a 10- or 30-mg/kg bolus dose. All animals survived 72 h. Neuroprotection was evaluated by balance beam testing and histopathology. The effects of NNZ-2566 on injury-induced changes in Bax and Bcl-2 proteins, activated microgliosis, neutrophil infiltration, and astrocyte reactivity were also examined. Behavioral results demonstrated that NNZ-2566 dose-dependently reduced foot faults by 19-66% after acute treatments, and 35-55% after delayed treatments. Although gross lesion volume was not affected, NNZ-2566 treatment significantly attenuated neutrophil infiltration and reduced the number of activated microglial cells in the peri-lesion regions of the PBBI. PBBI induced a significant upregulation in Bax expression (36%) and a concomitant downregulation in Bcl-2 expression (33%), both of which were significantly reversed by NNZ-2566. Collectively, these results demonstrated that NNZ-2566 treatment promoted functional recovery following PBBI, an effect related to the modulation of injury-induced neural inflammatory and apoptotic mechanisms.

PAN-811 provides neuroprotection against glutamate toxicity by suppressing activation of JNK and p38 MAPK.

In an earlier study, we demonstrated that PAN-811 (3-aminopyridine-2-carboxaldehyde thiosemicarbazone), a novel neuroprotectant, provides protection against glutamate, staurosporine, veratridine, or hypoxia/hypoglycemia toxicities in primary cortical neuronal cultures by upregulating Bcl-2 expression [R.-W. Chen, C. Yao, X.C. Lu, Z.-G. Jiang, R. Whipple, Z. Liao, H.A. Ghanbari, B. Almassian, F.C. Tortella, J.R. Dave. PAN-811 (3-aminopyridine-2-carboxaldehyde thiosemicarbazone), a novel neuroprotectant, elicits its function in primary neuronal cultures by upregulating Bcl-2 expression. Neuroscience 135 (2005) 191-201]. Both JNK (c-Jun N-terminal kinase) and p38 MAP (mitogen-activated protein) kinase activation have a direct inhibitory action on Bcl-2 by phosphorylation. In the present study, we continued to explore the mechanism of PAN-811 neuroprotection. Our results indicate that treatment of cultured cortical neurons with glutamate (100 microM) induces phosphorylation of both JNK and p38 MAPK. Specifically, pretreatment of neurons with 10 microM PAN-811 (an optimal neuroprotective concentration) for 1h, 4h, or 24h significantly suppresses glutamate-mediated activation of both JNK and p38 MAPK. Furthermore, the p38 MAPK-specific inhibitor SB203580 and the JNK-specific inhibitor SP600125 prevented glutamate-induced neuronal death in these primary cultures. Our results demonstrate that glutamate-induced phosphorylation of JNK and p38 MAPK is suppressed by PAN-811, which might contribute to Bcl-2 upregulation and PAN-811 neuroprotection.

Broad spectrum neuroprotection profile of phosphodiesterase inhibitors as related to modulation of cell-cycle elements and caspase-3 activation.

Cellular injury can involve the aberrant stimulation of cell cycle proteins in part through activation of phosphodiesterases (PDEs) and downstream expression of cell-cycle components such as cyclin D1. In mature non-proliferating cells activation of the cell cycle can lead to the induction of programmed cell death. In the present study, we investigated the in vitro neuroprotective efficacy and mechanism of action of vinpocetine (PDE1 inhibitor), trequinsin (PDE3 inhibitor), and rolipram (PDE4 inhibitor) in four mechanistically-distinct models of injury to primary rat cortical neurons as related to cell cycle regulation and apoptosis. Cellular injury was induced by hypoxia/hypoglycemia, veratridine (10 microM), staurosporine (1 microM), or glutamate (100 microM), resulting in average neuronal cell death rates of 43-48% as determined by MTT assay. Treatment with each PDE inhibitor (PDEI) resulted in a similar concentration-dependent neuroprotection profile with maximal effective concentrations of 5-10 microM (55-77% neuroprotection) in all four neurotoxicity models. Direct cytotoxicity due to PDE inhibition alone was not observed at concentrations below 100 microM. Further studies indicated that PDEIs can suppress the excitotoxic upregulation of cyclin D1 similar to the effects of flavopiridol, a cyclin-dependent kinase inhibitor, including suppression of pro-apoptotic caspase-3 activity. Overall, these data indicate that PDEIs are broad-spectrum neuroprotective agents acting through modulation of cell cycle elements and may offer a novel mode of therapy against acute injury to the brain.