Silencing the enhancer of zeste homologue 2,Ezh2,represses axon regeneration of dorsal root ganglion neurons

Recovery from injury to the peripheral nervous system is different from that of the central nervous system in that it can lead to gene reprogramming that can induce the expression of a series of regeneration-associated genes.This eventually leads to axonal regeneration of injured neurons.Although some regeneration-related genes have been identified,the regulatory network underlying axon regeneration remains largely unknown.To explore the regulator of axon regeneration,we performed RNA sequencing of lumbar L4 and L5 dorsal root ganglion(DRG)neurons at different time points(0,3,6,12 hours,1,3 and 7 days)after rat sciatic nerve crush.The isolation of neurons was carried out by laser capture microscopy combined with NeuN immunofluorescence staining.We found 1228 differentially expressed genes in the injured sciatic nerve tissue.The hub genes within these differentially expressed genes include Atf3,Jun,Myc,Ngf,Fgf2,Ezh2,Gfap and Il6.We verified that the expression of the enhancer of zeste homologue 2 gene(Ezh2)was up-regulated in DRG neurons after injury,and this up-regulation differed between large-and small-sized dorsal root ganglion neurons.To investigate whether the up-regulation of Ezh2 impacts axonal regeneration,we silenced Ezh2 with siRNA in cultured DRG neurons and found that the growth of the newborn axons was repressed.In our investigation into the regulatory network of Ezh2 by interpretive phenomenal analysis,we found some regulators of Ezh2(including Erk,Il6 and Hif1a)and targets(including Atf3,Cdkn1a and Smad1).Our findings suggest that Ezh2,as a nerve regeneration-related gene,participates in the repair of the injured DRG neurons,and knocking down the Ezh2 in vitro inhibits the axonal growth of DRG neurons.All the experimental procedures approved by the Administration Committee of Experimental Animals of Jiangsu Province of China(approval No.S20191201-201)on March 21,2019.

Low-frequency electrical stimulation improves neurite outgrowth of dorsal root ganglion neurons in vitro via upregulating Ca^(2+)-mediated brain-derived neurotrophic factor expression

Short-term, low-frequency electrical stimulation of neural tissues significantly enhances axonal regeneration of peripheral nerves following injury. However, little is known about the mechanisms of electrical stimulation to induce neurite outgrowth. In the present study, short-term, low-frequency electrical stimulation, using identical stimulation parameters of in vivo experiments, was administered to in vitro dorsal root ganglion （DRG） neurons. Enhanced neurite outgrowth, as well as synthesis and release of brain-derived neurotrophic factor （BDNF）, were examined in electrical stimulation-treated DRG neuronal cultures. Because the effects of electrical stimulation on neuronal intracellular signaling molecules are less reported, classic calcium intracellular signals are directly or indirectly involved in electrical stimulation effects on neurons. Cultured DRG neurons were pretreated with the calcium channel blocker nifedipine, followed by electrical stimulation. Results suggested that electrical stimulation not only promoted in vitro neurite outgrowth, but also enhanced BDNF expression. However, nifedipine reduced electrical stimulation-enhanced neurite outgrowth and BDNF biosynthesis. These results suggest that the promoting effects of electrical stimulation on DRG neurite outgrowth could be associated with altered calcium influx, which is involved induction of neuronal BDNF expression and secretion.

Stimulatory Effects of NMDA on Intracellular Ca^(2+) Nonlinear Kinetic Model in Rat Dorsal Root Ganglion Neurons

The present study revealed the stimulatory effects of NMDA on intracellular ca 2+ concentration in rat dorsal root ganglion (DRG) neurons. Fura 3/AM, an intracellular calcium fluorescent indicator was used to monitor the fluctuation of 〔ca 2+ 〕 i. Here we present the evidence that (1) Confocal microscopy resolved the cells of three different sizes, based on which a cell diameter distribution histogram was drawn. The fluorescence signals originated from the cells of different sizes, small size (diameter<30μm), medium size (diameter between 30 to 50μm),and large size (diameter>50μm); presumably intracellular Ca 2+ concentration was different in the cells of different sizes. (2) The time related variation of fluorescence intensity was observed. In particular, the fluorescence intensity in 0 Ca 2+ bath solution was affected by the application of high ca 2+ solution. (3) In 0 ca 2+ bath solution the intracellular Ca 2+ concentration nonlinear properties of distinct diameter cells was described. (4) A kind of SETAR model was fitted with a medium sized cell.(5)The residuals from the fitted model were tested to see whether they were plausibly Gaussian. These findings indicated that in distinct types of cells intracellular Ca 2+ concentration had different characteristics in different DRG neurons, and contributed to different functions of these neurons. Besides, the established threshold autoregressive model can share intracellular ca 2+ with the main nonlinear kinetic

Effect of type-2 astrocytes on the viability of dorsal root ganglion neurons and length of neuronal processes

The role of type-2 astrocytes in the repair of central nervous system injury remains poorly un- derstood. In this study, using a relatively simple culture condition in vitro, type-2 astrocytes, differentiated from oligodendrocyte precursor cells by induction with bone morphogenetic pro- tein-4, were co-cultured with dorsal root ganglion neurons. We examined the effects of type-2 astrocytes differentiated from oligodendrocyte precursor cells on the survival and growth of dorsal root ganglion neurons. Results demonstrated that the number of dorsal root ganglion neurons was higher following co-culture of oligodendrocyte precursor cells and type-2 astrocytes than when cultured alone, but lower than that of neurons co-cultured with type-1 astrocytes. The length of the longest process and the length of all processes of a single neuron were shortest in neurons cultured alone, followed by neurons co-cultured with type-2 astroc^es, then neurons co-cultured with oligodendrocyte precursor cells, and longest in neurons co-cultured with type-1 astrocytes. These results indicate that co-culture with type-2 astrocytes can increase neuronal survival rate and process length. However, compared with type-1 astrocytes and oligodendrocyte precursor cells, the promotion effects of type-2 astrocytes on the growth of dorsal root ganglion neurons were weaker.

Combination of Quercetin, Cinnamaldehyde and Hirudin Protects Rat Dorsal Root Ganglion Neurons against High Glucose-Induced Injury through Nrf-2/HO-1 Activation and NF-κB Inhibition

Objective： TO examine the effects of the combination of quercetin （Q）, cinnamaldehyde （C） and hirudin （H）, a Chinese medicine formula on high glucose （HG）-induced apoptosis of cultured dorsal root ganglion （DRG） neurons. Methods： DRG neurons exposed to HG （45 mmol/L） for 24 h were employed as an in vitro model of diabetic neuropathy. Cell viability, reactive oxygen species （ROS） level and apoptosis were determined. The expression of nuclear factor of Kappa B （NF- κB）, inhibitory kappa B α （IκBα ）, phosphorylated IκBα and Nf-E2 related factor 2 （Nrf2） were examined using reverse transcription-polymerase chain reaction （RT-PCR） and Western blot assay. The expression of hemeoxygenase-1 （HO-1）, interleukin-6 （IL-6）, tumor necrosis factor （TNF-α） and caspase-3 were also examined by RT-PCR and Western blot assay. Results： HG treatment markedly increased DRG neuron apoptosis via increasing intracellular ROS level and activating the NF- κB signaling pathway （P〈0.05）. Co-treatment with Q, C, H and their combination decreased HG-induced caspase-3 activation and apoptosis （P〈0.05 or P〈0.01）. The expressions of NF- κB, IL-6 and TNF-α were down- regulated, and Nrf2/HO-1 expression was up-regulated （P〈0.05 or P〈0.01）. QCH has better effect in scavenging ROS, activating Nrf-2/HO-1, and down-regulating the NF- κB pathway than other treatment group. Conclusions： DRG neurons＇ apoptosis was increased in diabetic conditions, which was reduced by QCH formula treatment. The possible reason could be activating Nrf-2/HO-1 pathway, scavenging ROS, and inhibition of NF- κB activation. The effect of QCH combination was better than each monomer or the combination of the two monomers.

Effects of Hirudin on High Glucose-Induced Oxidative Stress and Inflammatory Pathway in Rat Dorsal Root Ganglion Neurons

Objective:To investigate protective effects of hirudin on oxidative stress and apoptosis of spinal dorsal root ganglion cells in high-glucose rats at the cellular and molecular level.Methods:Dorsal root ganglion neurons(DRGn)were harvested from embryonic day in 15 SD rats,purified and identificated after primary culture.They were divided into the normal control group,high-glucose(HG)group,positive control(alpha-lipoic acid,ALA)group,low-dose hirudin group(H1),medium-dose hirudin group(H2)and high-dose hirudin group(H3).The control group was cultured by neuron specific culture medium,while the HG group was cultured by neuron specific culture medium and 20 mmol/L glucose(HG medium).The hirudin groups were cultured by HG medium+0.25 IU/mL hirudin(H1),HG medium+0.5 IU/mL hirudin(H2)and HG medium+1 IU/mL hirudin(H3).The ALA group was cultured by HG medium +100μmol/L ALA.3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylt etrazolium bromide(MTT)assay was used to explore the optimum concentration and intervention time.Flow cytometry assay was used to detect the level of reactive oxygen series(ROS).Western blot and quantificational realtime polymerase chain reaction(qRT-PCR)were used to detect the expression of protein and mRNA of nuclear factor erythroid 2-related factor 2(Nrf-2),hemeoxygence-1(HO-1),nuclear factor-κB(NF-κB)and Caspase-3.TUNEL assay was used to test the apoptosis rate of different groups.Results:After 24 h of culture,the cell activity of hirudin and ALA groups were higher than that of HG group,and there was a statistical difference between the H1 group and HG group(P<0.05).In hirudin groups,the apoptosis rate of cells,the expression of activated Caspase-3 protein and Caspase-3 mRNA were lower than those of HG group(P<0.01),higher than those of ALA group(P<0.01 or P<0.05).The ROS level of hirudin groups was higher than that of ALA group(P<0.01),lower than that of HG group(P<0.01 or P<0.05).The expression of NF-κB(P65)protein in H3 group were lower than those of HG group(P<0.05).The expression of Nrf-2 protein in hirudin groups was higher than that of HG group(P<0.01),lower than that of ALA group(P<0.01 or P<0.05).The expression of HO-1 protein in hirudin groups was lower than that of ALA group(P<0.01 or P<0.05),higher than that of HG group(P<0.01 or P<0.05).Conclusions:The activity of DRGn cells can be promoted by hirudin under HG conditions.The effects of hirudin on the inhibition of HG on DRGn cells damage mainly include scavenging ROS,up-regulating Nrf-2/HO-1 pathway,inhibiting activation of NF-κB pathway,down-regulating the expression of and Caspase-3 and reducing DRGn cell apoptosis.

Physiological relevance of soma secretion in dorsal root ganglion neurons

Dorsal root ganglion (DRG) cells are primary sensory neurons and are important in pain. Recently, a distinct type of exocytosis, Ca2+ independent but voltage-dependent, is found

Modulation of dragon's blood on tetrodotoxin-resistant sodium currents in dorsal root ganglion neurons and identification of its material basis for efficacy

To clarify the modulation of dragon's blood on the tetrodotoxin-resistant (TTX-R) sodium currents in dorsal root ganglion (DRG) neurons and explore its corresponding material basis for the efficacy, using whole-cell patch clamp technique, the effects of dragon's blood and the combined effects of three components (cochinchinenin A, cochinchinenin B, and loureirin B) extracted from dragon's blood on the TTX-R sodium currents in acute-isolated DRG neurons of rats were observed. According to the operational definition of material basis for the efficacy of TCM established, the material basis of the modulation on the TTX-R sodium currents in DRG neurons of dragon's blood was judged from the experimental results. The drug interaction equation of Greco et al. was used to assess the interaction of the three components extracted from dragon's blood. This investigation demonstrated that dragon's blood suppressed the peak TTX-R sodium currents in a dose-dependent way and affected the activations of TTX-R sodium currents. The effects of the combination of cochinchinenin A, cochinchinenin B, and loureirin B were in good agreement with those of dragon's blood. Although the three components used alone could modulate TTX-R sodium currents, the concentrations of the three components used alone were respectively higher than those used in combination when the inhibition rates on the TTX-R sodium currents of them used alone and in combination were the same. The combined effects of the three components were synergistic. These results suggested that the interference with pain messages caused by the modulation of dragon's blood on TTX-R sodium currents in DRG neurons may explain some of the analgesic effect of dragon's blood and the corresponding material basis for the efficacy is the combination of cochinchinenin A, cochinchinenin B, and loureirin B.

Effects of dragon’s blood resin and its component loureirin B on tetrodotoxin-sensitive voltage-gated sodium currents in rat dorsal root ganglion neurons

Using whole-cell patch clamp technique on the membrane of freshly isolated dorsal root ganglion (DRG) neurons, the effects of dragons blood resin and its important component loureirin B on tetrodotoxin-sensitive (TTX-S) voltage-gated sodium currents were observed. The results show that both blood resin and loureirin B could suppress TTX-S voltage-gated sodium currents in a dose-dependent way. The peak current amplitudes and the steady-state activation and inactivation curves are also made to shift by 0.05% blood resin and 0.2 mmol/L loureirin B. These results demonstrate that the effects of blood resin on TTX-S sodium current may contrib-ute to loureirin B in blood resin. Perhaps the analgesic effect of blood resin is caused partly by loureirin B directly interfering with the nociceptive transmission of primary sensory neurons.

The sensitivity of neurons with non-periodic activity to sympathetic stimulation in rat injured dorsal root ganglion

Objective The relationship between compressed dorsal root ganglion （DRG） neurons and firing pattern and sensitivity of neurons was studied in chronically the Hindmarsh-Rose （HR） neuronal model. Methods Spontane- ous activities from single fibers of chronically compressed DRG neurons in rats were recorded, and divided into periodic and non-periodic firing patterns. The sensitivity of the two kinds of firing pattern neuron to sympathetic stimulation （SS） was compared. Result It was found that 27.3% of periodic firing neurons and 93.2% of non-periodic firing neurons responded to SS respectively （ periodic vs non-periodic, P 〈 0.01 ）. The responses to SS with different stimulation time were greater non-periodic firing neurons than periodic firing neurons （P 〈 0.01 ）. The non-periodic firing neurons obviously responded to SS. After the firing pattern of these neurons transformed to periodic firing pattern, their responses to SS disappeared or decreased obviously. The HR neuronal model exhibited a significantly greater response to perturbation in non-periodic （chaotic） firing pattern than in periodic firing pattern. Conelusion The non-periodic firing neurons with deterministic chaos are more sensitive to external stimuli than the periodic firing neurons.

The effects of rises in external K^+ on the hyperpolarization-activated cation current I_h in rat dorsal root ganglion neurons

The effects of rises in external K+(Kext) were examined on the hyperpolarization-activated cation current(Ih) in rat dorsal root ganglion neurons using the whole-cell patch clamp technique.The results showed that Kext increased Ih in a certain concentration and voltage-dependent manner.At the basal Kext level(4 mmol/L),Ih had a maximal amplitude of 1085 ± 340 pA which was enhanced by ～45% and ～92% at 8 and 16 mmol/L Kext,respectively.The midpoint activation voltage was significantly shifted from -98 mV in the hyperpolarizing direction by 8 and 12 mV at 8 and 16 mmol/L Kext,respectively with alteration of the activation course of Ih.The short time constants of activation became longer with the increasing amplitude of the command potential upon rises in Kext.The long time constants became shorter.The reversal potentials were shifted in the positive direction without significant alterations upon rises in Kext.According to the functional role of Ih,Kext increased Ih,resulting in an enhanced neuronal excitability,which might produce activation potential abnormality and perhaps neuropathic pain involved.

Effects of Intrathecally Administerd NaV1.8 Antisense Oligonucleotide on the Expression of Sodium Channel mRNA in Dorsal Root Ganglion

Neuropathic pain has been hypothesized to be the result of aberrant expression and function of sodium channels at the site of injury. To investigate the effects of NaV1.8 antisense oligonucleotide on the expression of sodium channel mRNA in dorsal root ganglion （DRG） neurons in chronic neuropathic pain. 24 Sprague-Dawley rats weighing 200--260 g were anesthetized with the intraperitoneal injection of 300 mg· kg^-1 choral hydrate. The CCI model was made by loose ligation of sciatic nerve trunk by 4--0 chromic gut. The mechanical and thermal pain threshold were measured before operation and 1, 3, 5, 7, 9, 11, 13 days after operation. A PE-10 catheter was implanted in subarachnoid space at lumbar region. On the 7th postoperative day the animals were randomly divided into 4 groups. The drugs were injected intrathecally twice a day for 5 consecutive days in group 2--4. The animals were decapitated 14 days after the surgery. The L4--L6 DRG of the operated side was removed and crushed, and total RNA was extracted with Trizol reagent. The contralateral side was used as control. The change of NaV1.8 sodium channel transcripts was determined by RT-PCR. Pain threshold was significantly lowered after CCI as compared with that in control group and was elevated 3 days after antisense oligonucleotide injection. Sensory neuron specific TTX-R sodium channel NaV1.8 transcript was down-regulated after antisense oligonucleotide injection at the dosage of 45 μg as compared with that in CCI group （P〈0.01）, and it was even greater at the dosage of 90 μg. The intrathecally injected NaV1.8 antisense oligonucleotide can reduce the mechanical allodynia and thermal hyperalgesia partially by downregulating the SNS transcript expression.

Pulsed electrical stimulation protects neurons in the dorsal root and anterior horn of the spinal cord after peripheral nerve injury

Most studies on peripheral nerve injury have focused on repair at the site of injury, but very few have examined the effects of repair strategies on the more proximal neuronal cell bodies. In this study, an approximately 10-mm-long nerve segment from the ischial tuberosity in the rat was transected and its proximal and distal ends were inverted and sutured. The spinal cord was subjected to pulsed electrical stimulation at T10 and L3, at a current of 6.5 m A and a stimulation frequency of 15 Hz, 15 minutes per session, twice a day for 56 days. After pulsed electrical stimulation, the number of neurons in the dorsal root ganglion and anterior horn was increased in rats with sciatic nerve injury. The number of myelinated nerve fibers was increased in the sciatic nerve. The ultrastructure of neurons in the dorsal root ganglion and spinal cord was noticeably improved. Conduction velocity of the sciatic nerve was also increased. These results show that pulsed electrical stimulation protects sensory neurons in the dorsal root ganglia as well as motor neurons in the anterior horn of the spinal cord after peripheral nerve injury, and that it promotes the regeneration of peripheral nerve fibers.

Endogenous neurotrophin-3 promotes neuronal sprouting from dorsal root ganglia

In the present study, we investigated the role of endogenous neurotrophin-3 in nerve terminal sprouting 2 months after spinal cord dorsal root rhizotomy. The left L1-5 and L7-S2 dorsal root ganglia in adult cats were exposed and removed, preserving the L6 dorsal root ganglia. Neurotrophin-3 was mainly expressed in large neurons in the dorsal root ganglia and in some neurons in spinal lamina II. Two months after rhizotomy, the number of neurotrophin-3-positive neurons in the spared dorsal root ganglia and the density of neurite sprouts emerging from these ganglia were increased. Intraperitoneal injection of an antibody against neurotrophin-3 decreased the density of neurite sprouts. These findings suggest that endogenous neurotrophin-3 is involved in spinal cord plasticity and regeneration, and that it promotes axonal sprouting from the dorsal root ganglia after spinal cord dorsal root rhizotomy.

Hyperexcitable neurons and altered non-neuronal cells in the compressed spinal ganglion

The cell body or soma in the dosal root ganglion(DRG) is normally excitable and this excitability can increase and persist after an injury of peripheral sensory neurons.In a rat model of radicular pain,an intraforaminal implantation of a rod that chronically compressed the lumbar DRG("CCD" model) resulted in neuronal somal hyperexcitability and spontaneous activity that was accompanied by hyperalgesia in the ipsilateral hind paw.By the 5th day after onset of CCD,there was a novel upregulation in neuronal expression of the chemokine,monocyte chemoattractant protein-1(MCP-1 or CCL2) and also its receptor,CCR2.The neurons developed,in response to topically applied MCP-1,an excitatory response that they normally do not have.CCD also activated non-neuronal cells including,for example,the endothelial cells as evidenced by angiogenesis in the form of an increased number of capillaries in the DRG after 7 days.A working hypothesis is that the CCD induced changes in neurons and non-neuronal cells that may act together to promote the survival of the injured tissue.The release of ligands such as CCL2,in addition to possibly activating nociceptive neurons(maintaining the pain),may also act to preserve injured cells in the face of ischemia and hypoxia,for example,by promoting angiogenesis.Thus,somal hyperexcitability,as often said of inflammation,may represent a double edged sword.

Changes in skin levels of two neutotrophins (glial cell line derived neurotrohic factor and neurotrophin-3) cause alterations in cutaneous neuron responses to mechanical stimuli

Neurotrophins are important for the development and maintenance of both high and low threshold mechanoreceptors(HTMRs and LTMRs).In this series of studies,the effects of constitutive overexpression of two different neurotrophins,neurotrophin-3(NT-3) and glial cell line derived neurotrohic factor(GDNF),were examined.Previous studies indicated that both of them may be implicated in the normal development of mouse dorsal root ganglion(DRG) neurons.Neurons from mice transgenically altered to overexpress NT-3 or GDNF(NT-3-OE or GDNF-OE mice) in the skin were examined using several physiological,immunohistochemi-cal and molecular techniques.Ex vivo skin/nerve/DRG/spinal cord and skin/nerve preparations were used to determine the response characteristics of the cutaneous neurons;immunohistochemistry was used to examine the biochemical phenotype of DRG cells and the skin;RT-PCR was used to examine the levels of candidate ion channels in skin and DRG that may correlate with changes in physiological responses.In GDNF-OE mice,I-isolectin B4(IB4)-immunopositive C-HTMRs(nociceptors),a large percentage of which are sensitive to GDNF,had significantly lower mechanical thresholds than wildtype(WT) neurons.Heat thresholds for the same cells were not different.Mechanical sensitivity changes in GDNF-OE mice were correlated with significant increases in acid sensing ion channels 2a(ASIC2a) and 2b(ASIC2b) and transient receptor potential channel A1(TRPA1),all of which are putative mechanosensitive ion channels.Overexpression of NT-3 affected the responses of A-LTMRs and A-HTMRs,but had no effect on C-HTMRs.Slowly adapting type 1(SA1) LTMRs and A-HTMRs had increased mechanical sensitivity compared to WT.Mechanical sensitivity was correlated with significant increases in acid-sensing ion channels ASIC1 and ASIC3.This data indicates that both neurotrophins play roles in determining mechanical thresholds of cutaneous HTMRs and LTMRs and that sensitivity changes involve the ASIC family of putative mechanoreceptive ion channels.

The Endocannabinoid, 2-Arachidonoyl Glycerol, Induces Growth Cone Collapse and Neurite Retraction in Growing Peripheral Sensory Neurons

Cannabis has a detrimental impact on the developing nervous system. Therefore, regular consumption of cannabis by pregnant and lactating woman poses a potential risk to neuronal growth in fetuses and infants. Indeed, endogenous cannabis-like molecules called endocannabinoids regulate many physiological processes, including neurogenesis, axon guidance, and synaptic plasticity through CB1 receptors. To investigate the physiological role of CB1 receptors on peripheral sensory nerve growth, the endocannabinoid 2-arachidonoyl glycerol was added to cultured chick dorsal root ganglion neurons. This compound inhibited neurite elongation and induced growth cone collapse in a dose- and time-dependent manner. These data suggest that caution should be exercised regarding maternal cannabis use during pregnancy. Because ectopic sprouting and abnormal neuronal network connections are considered to be a cause of neuropathic pain, our current data imply an additional role of endocannabinoids as inhibitors of the formation of pain-maintenance networks.

野木瓜注射液镇痛作用的药理机制研究

目的研究野木瓜注射液对背根神经节细胞电压门控性钠通道电流的影响,分析野木瓜注射液阻滞神经传导、产生镇痛作用的药理机制。方法在急性分离的大鼠背根神经节细胞膜上,进行全细胞膜片钳记录,观察10%、25%和50%的野木瓜注射液对电压门控性钠通道电流的影响。结果野木瓜注射液浓度依赖地抑制背根神经节细胞钠通道电流峰值,并影响通道的激活和失活过程。结论野木瓜注射液除影响髓鞘和轴突膜结构外还通过调制初级感觉神经元电压门控性钠通道,影响痛觉信息中枢传入产生镇痛作用。

筋脉通含药血清对高糖培养背根神经节神经元氧化应激及细胞凋亡的影响

目的探讨筋脉通(菟丝子、女贞子、桂枝、延胡索、水蛭、细辛等)含药血清对高糖培养大鼠背根神经节神经元(DRGn)氧化应激及细胞凋亡的影响。方法雄性SD大鼠随机分为3组,分别灌胃筋脉通、维生素C或生理盐水制备含药血清和对照血清。从孕15 d的SD胎鼠背根神经节取材制备细胞悬液。MTT法确定高糖浓度、筋脉通含药血清浓度及指标检测时间点。将体外培养的DRGn分为高糖组、筋脉通组(加入筋脉通含药血清)、维生素C组(加入维生素C含药血清)及正常对照组,培养24 h后,采用荧光探针法检测DRGn中超氧阴离子、线粒体膜电位水平,免疫印迹法+实时荧光定量聚合酶链式反应法检测Bcl-2和Caspase-3的mRNA及其蛋白表达,原位末端标记法检测凋亡细胞。结果与正常对照组相比,高糖组超氧阴离子水平显著升高,Caspase-3 mRNA及其蛋白表达、细胞凋亡率均显著升高,而线粒体膜电位、Bcl-2 mRNA及其蛋白表达显著降低(P<0.01);与高糖组比较,筋脉通组超氧阴离子水平明显降低,Caspase-3 mRNA及其蛋白表达、细胞凋亡率均明显降低,而线粒体膜电位、Bcl-2 mRNA及其蛋白表达显著升高(P<0.01),其作用明显优于维生素C组(P<0.01)。结论筋脉通含药血清可通过抑制高糖所致DRGn氧化应激、减少细胞凋亡起到防治糖尿病周围神经病变的作用。

大鼠脊髓背根神经节神经元的纯化培养

目的:建立一种简单、稳定、高效的大鼠脊髓背根神经节神经元原代纯化培养方法。方法:取新生SD大鼠的脊髓背根神经节,采用胰蛋白酶消化法,制成单细胞悬液,加入阿糖胞苷以纯化细胞,培养于含10%胎牛血清与重组人胶质细胞源性神经营养因子的DF12培养基中,观察神经元生长状况,用细胞计数和神经元特异性烯醇化酶(NSE)免疫细胞化学染色测定细胞纯度。结果:培养的脊髓背根神经节神经元生长状态正常,有神经突起生长和标记蛋白的表达,可达到90%左右的纯度。结论:本培养方法简单、稳定、高效,为对神经元进一步的深入研究提供了实验模型。