Objective To investigate the inhibitory effects of N-acetylcysteine (NAC) on inflammatory factors after acute spinal cord injury, and the mechanisms thereof. Methods A total of 54 clean and healthy adult female SD rats were divided into three groups according to the principle of randomization:simple laminectomy group (Sham group), spinal cord injury group (SCI group) and N-acetylcysteine group (NAC group), with 18 rats in each group. The Sham group was treated with T9-10 laminectomy only without spinal cord injury. Aneurysm clamp was used to establish rat model of T9-10 spinal cord injury in SCI group and NAC group. At the time of 15 min and 12 h after injury, the rats of NAC group were injected N-acetylcysteine intraperitoneally (150 mg/kg). At the time of 24 h post modeling, 12 rats were sacrificed in each group for observing the severity of tissue injury by using hematoxylin-eosin (HE) staining (6 rats), and detecting the contents of inflammation factors including tumor necrosis factor (TNF)- α and interleukin (IL)- 6 by using enzyme- linked immunosorbent assay (ELISA) (6 rats). The remaining 6 rats in each group were raised for 8 weeks. During the first week, the ones in NAC group were injected NAC twice a day at 12 h intervals for 7 d. Additionally, the neurological function evaluation was performed at week 1, week 2, week 4, week 6 and week 8 after injury in rats by using the spinal cord injury motor function score (BBB) and the inclined plate test. Results The results of HE staining showed that the spinal cord was intact without hemorrhage and inflammatory cell infiltration in Sham group. The morphology and inflammatory status were significantly worse in SCI group than those in NAC group and Sham group. The results of ELISA showed that the expressions of TNF-αand IL-6 were significantly higher in SCI group and NAC group than those in Sham group (P<0.05), while the expression levels of TNF-αand IL-6 were significantly lower in NAC group than those of SCI group (P<0.05). The BBB scores and inclined plate test showed that both were significantly lower in SCI group and NAC group than those of Sham group (P<0.05), and the results were better in NAC group than those of SCI group. Conclusion NAC may promote the recovery of neurological function in rats by reducing the local inflammatory response through diminishing the contents of TNF-αand IL-6 in spinal cord.

BACKGROUND:Oligodendrocytes are mostly differentiated from oligodendrocyte precursor cel s. A suitable medium and cel seeding density have a significant impact on the process of the isolation of oligodendrocyte precursor cel s to obtain oligodendrocytes. OBJECTIVE:To explore the optimization of oligodendrocyte culture conditions. METHODS:Oligodendrocyte precursor cel s isolated from the newborn rats 48 hours after birth were cultured in DMEM/high glucose medium or DMEM/F12 medium using seeding densities of 2×104 cel s/cm2, 4×104 cel s/cm2, 8×104 cel s/cm2, 16×104 cel s/cm2, 32×104 cel s/cm2, and 64×104 cel s/cm2, respectively. Oligodendrocyte precursor cel s were induced to differentiate into oligodendrocytes at 72 hours after cel adhesion. Morphology of differentiated oligodendrocyte precursor cel s were observed under a light microscope, and the differentiation results were identified by immunofluorescence staining after 7-day induced differentiation. RESULTS AND CONCLUSION:Morphology of oligodendrocyte precursor cel s were recognized when cultured in DMEM/high glucose medium or DMEM/F12 medium using seeding densities of 2×104 cel s/cm2, 4×104 cel s/cm2, and 8×104 cel s/cm2, respectively. Immunofluorescence staining showed that myelin basic protein-positive cel s were found after 7-day induced differentiation, and the positive cel number were 16.40±3.30, 49.95±2.33, and 76.95±4.86 in DMEM/F12 medium, and 12.65±2.53, 32.10±1.17, and 54.05±1.56 in DMEM/high glucose medium (P<0.05). These findings indicate that DMEM/F12 medium is more suitable for culturing oligodendrocyte precursor cel s compared with DMEM/high glucose medium to some extent. The number of differentiated oligodendrocytes was gradual y increased with the enhanced seeding density of oligodendrocyte precursor cel s, and the seeding densities from 4×104 to 8×104 cel s/cm2 were appropriate for the observation of cel morphology.

The study of brain-machine interfaces ( BMI) based on humans or animals is expected to improve the living conditions of patients with brain injury, nervous system disease and limb movement disorders.Considerable progress has been made over the past ten years, which is gradually being used to address the long-term and stability issues of BMIs technology.The result of study on safety and security of BMIs has led to the appearance of brain control animals.In this paper, the development of BMI technology and the application prospects of brain control animals are reviewed.

Objective To explore the correlation between the changes of mitochondrial DNA (mtDNA) copy number of peripheral blood leukocytes and the degree of neurological impairment after traumatic brain injury (TBI).Methods A total of 40 Sprague Dawley rats were randomly divided into 4 groups:control group (n=10),mild TBI group (n=10),moderate TBI group (n=10) and severe TBI group (n=10).The cortical impact injury method to construct TBI rat model of different damage degree.The neurological score (mNSS,screen test,open field test) after TBI 24 h,48 h,72 h was performed and the orbital venous plexus blood genomic DNA was extracted.The real-time PCR method to measure the relative mitochondrial DNA copy number.After the experiment,the rats were euthanized,and the brain tissue was stained with hematoxylin-eosin staining(HE).Results There were significant differences in the HE staining findings of brain tissue pathology (P＜ 0.05).Each group of rats with brain injury after peripheral blood mtDNA copy number in 24 h (9.63±3.62,P＜0.05) and 48 h (9.80±3.58,P＜0.05) increased,began to decline at 72 h (4.97±2.68,P＜0.05).The rats mNSS scores were related with the mtDNA copy number after TBI 24 h (r=0.578,P＜0.05) and 48 h (r=0.559,P＜0.05),and not related to TBI 72 h (r=0.487,P＞0.05).The rats screen test scores were related with the mtDNA copy number after TBI 24 h (r=0.573,P＜0.05) and 48 h (r =0.501,P＜0.05),and not related to TBI 72 h (r=0.273,P＞0.05).The rats level scores of open field test were negatively correlated with the mtDNA copy number after TBI24 h (r=-0.662,P＜0.05) and 48 h (r=-0.507,P＜0.05),and not negatively correlated to TBI 72 h (r=-0.410,P＞0.05).The rats vertical scores of open field test were negatively correlated with the mtDNA copy number after TBI 24 h (r=-0.662,P＜0.05)and 48 h (r =-0.607,P＜ 0.05),and not negatively correlated to TBI 72 h (r =-0.141,P＞ 0.05).Conclusion TBI is related with the copy of early peripheral white blood cell number and mtDNA of rat nerve function damage,and mtDNA copy number of peripheral white blood cell may become a clinical evaluation of TBI neural function damage degree of a potential biomarker.