Background Traumatic optic neuropathy (TON) is an acute injury of the optic nerve secondary to trauma.As an important immune cell, microglia is involved in a variety of pathologic changes in central nervous system diseases and eye diseases.However, the role of microglia in the lesion development and neural restoration in TON is still unclear. Objective This study was to compare the differences of microglial activation between optic nerve axon and retina after optic nerve crush injury, including the morphological changes, number, and distribution of microglia. Methods Thirty-five SPF female Sprague-Dawley (SD) rats were numbered from 1 to 35 and randomized into normal control group, sham operation group and modeling 6-hour group, modeling 3-day group, modeling 7-day group, modeling 14-day group and modeling 30-day group according to the random number table.Optic nerve injury models were established by crushing optic nerve at retrobulbar 2 mm for 10 seconds.The same operation was carried out but not clamping optic nerve in the sham operation group, and normal control group without any treatment.The morphological changes, number and distribution of microglia in retina and optic nerve axon were assayed and compared by immunofluorescence staining with lectin-FITC fluorescence labeled antibody detection.The use and care of the experimental animals complied with ARVO. Results Microglia were displayed mainly in inner plexiform layer (IPL), and a few of microglia were in inner nuclear layer (INL) and ganglion cell layer (GCL), not any microglia were seen in outer nuclear layer (ONL) and outer plexiform layer (OPL) in the normal control group and sham operation group.Thining synapsis and secondary branches were seen with the dendroid in shape in normal control group.In the model groups, the microglia were more in GCL compared with sham operation group and showed amoeboid microglial cells.The number of microglia in retinas was 6.40±1.52, 7.20±2.05, 12.00±3.54, 14.00±4.06, 18.00±4.36, 18.40±3.13 and 10.80±1.92 in the normal control group, sham operation group, modeling 6-hour group, modeling 3-day group, modeling 7-day group, modeling 14-day group and modeling 30-day group, respectively, and the microglia number were significantly increased in modeling 6-hour group, modeling 3-day group, modeling 7-day group, modeling 14-day group and modeling 30-day group in comparison with the normal control group, and in the modeling 30-day group, the microglial number in retinas was significantly reduced in comparison with the modeling 7-day group and modeling 14-day group (all at P<0.05). The activited microglia in the retinas were nuch more in the modeling 3-day group, modeling 7-day group and modeling 14-day group than that in the sham operation group (P=0.024, 0.009, 0.023). In the optic nerve, the microglial cells were small in size and sparse in arrangement in the normal control group and sham operation group.The cells were enlarged with the amoeboid-like in shape in the model groups and distributed in injury area.The cell number was significantly higher in the modeling 6-hour group, modeling 3-day group, modeling 7-day group and modeling 14-day group than that in the normal control group (P=0.007, 0.001, 0.003, 0.014). The cell number in modeling 30-day group was significnatly reduced in comparison with the modeling 3-day group, modeling 7-day group and modeling 14-day group (all at P<0.05). The activated microglial number were significantly elevated in the modeling 6-hour group, modeling 3-day group, modeling 7-day group compared with the sham operation group (P=0.005, 0.004, 0.030), and the cell number in the modeling 30-day group was evidently lower than that in the modeling 3-day group (P=0.021, 0.004). The cells of activated state in the optic nerve were significantly increased in modeling 6-hour group and modeling 14-day group. Conclusions Microglia are activated and keep increasing number in retina and optic nerve at a certain period after optic nerve injury, and these changes are earlier and more distinct in optic nerve axon than those in retina. Key words: Optic nerve/injury; Retina; Microglia; Activation

Background Isoflurane is an inhaled anesthetic widely used in pediatric and obstetric operations, due to its advantages such as anesthesia depth which is easy to control and little influence on the circulation. Objective Recent reports showed that repeated or long-time exposure to anesthetics at the young stage may cause deficient memory in the future. Therefore, increasing attentions have been drawn on isoflurane's mechanism about neurological damages. Content This paper summarized the toxic mechanism of isoflurane in the recent five years, and synaptic plasticity damages can cause neurotoxicity, inhibit N-methyl-D-aspartate(NMDA) receptor and stimulate amino acid type A receptor (GABAAR) and affect long-term potentiation, calcium homeostasis, and activate neurotrophins to produce apoptotic pathway, and other possible toxic mechanisms. Trend This paper can further determine the research direction, providing references for transform of basic research data into clinical practice as well as for the research and development of new protective drugs. Key words: Isoflurane; Developmental brain; Apoptosis; Neurotoxicity; Synapsis

REC8 density along chromosomes prevents illegitimate synapsis

Objective To observe the influence of oleanolic acid on the ethology of 9-month-old mice, the completeness of synapsis structure and the expression of cAMP-response element binding protein(CREB) in cortex and hippocampus. Methods Thirty 9-month-old healthy male SMAP8 mice were randomly divided into model group, oleanolic acid group and aricept group, and with 10 rats in each group, while 10 healthy male mice of the same age and species as normal group.Oleanolic acid group and aricept group were given intragastric administration with corresponding drugs, while the normal group and model group were given the same amount of physiological saline. 4 weeks later, the ethology changes were observed by Morris water maze and morphology changes of hippocampus neurons were viewed by electron microscope and the expression of CREB was detected by Western Blot. Results (1)Morris water maze results suggested that compared with the normal group, the latency time in the model group mice was longer, which were ((83.33±4.96) s, (75.13±6.01) s, ( 71.75±7.77) s, (63.40±8.93) s, (60.97±8.38) s), while compared with the model group, the latency time in the oleanolic acid group and the aricept group was remarkably shorter(P<0.05), which were (75.97±4.49)s, (64.98±4.93)s, (64.16±6.23)s, (53.47±5.99)s, (47.91±7.64)s and (71.30±7.65)s, (63.32±7.57)s, (59.82±4.69)s, (52.28±5.90)s, (46.22±7.27)s respectively. In the spatial probe trial, compared with the normal group, the crossing times of the model was less, while compared with the model one, the crossing times of the oleanolic acid group and the aricept group was more(P<0.05). (2)Compared with the normal group, the number of synapses in the model group was smaller, in which the synaptic cleft was mixed with the front of synapses severely swollen, uninform synaptic vesicles and few clear outlines of mitochondrias. While the oleanolic acid group and the aricept group had clear synapses outlines with the front of synapses slightly swollen, intensive and uniform synaptic vesicles and clear mitochondrias with their cristae not easy to be seen. (3)The Western Blot showed that compared with the normal group, there was a decline in the CREB expression both in the cortex and hippocampus in the model group, while compared with the model group, there was a rise in the oleanolic acid group as well as the aricept group(P<0.05). Conclusion Oleanolic acid can improve the learning and memorizing of model rats, which is possibly related to the increased expression of CREB protein to protect the synapses structure of model mice. Key words: Oleanolic acid; Alzheimer's Disease; SAMP8 mice; Synapsis electron microscope; cAMP-response element binding protein

Objective To establish normative data for the fetal cisterna magna septa (CMS) at various gestational age,and to evaluate its clinical significance.Methods A total of consecutive fetal between 14 and 40 gestational week(GW) were included in this prospective study.The length and width of CMS were measured by two-dimensional ultrasonography.Regression analysis was used to study the relationship between the width and length of the fetal cisterna magna septa and gestational age.Twenty-five case of fetuses with the absence of CMS and 12 case of fetuses with the enlargement of CMS were retrospectively analyzed in the past six years in our hospital.Results ①The fetal CMS length and width increased gradually between 14 and 22 GW,then plateaued between 23 GW and 36 GW,and decreased after 37 GW.This ultrasonographic pattern was in agreement with normal development of rhombencephalon.②The absence of CMS in the fetuses were common in Dandy-Walker syndrome,holoprosencephaly,severe hydrocephalus,neural tube defects,rhombencephalon synapsis and Arnold-Chiari malformation.The enlargement of CMS in the fetuses may be shown in physiologic enlargement of posterior fossa.ConclusionsCMS is a potential new marker for normal development of rhombencephalon.The enlargement and absence of CMS are related to various malformations of central neural system,especially in the abnormalities of posterior fossa. Key words: Ultrasonography,prenatal; Cisterna magna; Cranial fossa,posterior

Objective To investigate the effects of intrathecal (IT) ketamine on the synapsis remodeling in the spinal dorsal horn during devolopment of morphine tolerance in a rat model of neuropathic pain (NP). Methods Male SD rats weighing 200-250 g were used in this study. IT catheter was placed in the subarachnoid space according to Yaksh. Forty-eight SD rats in which IT catheter was successfully placed were randomly divided into 6groups (n=8 each): group sham operation (group S); group NP; group normal saline 20 μl IT(group NS);group morphine 20 μg IT (group M); group ketamine 50 μg IT (group K) and group morphine 20 μ g + ketamine 50 μg IT (group MK). NP was induced by compression of right L4,5 dorsal root ganglions with steel wire inserted through L4,5 intervertebral foramen in NP,M,K and MK groups. Normal saline or morphine and/or ketamine were injected IT once a day for consecutive 14 days. Paw withdrawal threshold (PWT) to mechanical stimulation and paw withdrawal latency (PWL) to a thermal nociceptive stimulus were measured on 0, 1, 3, 5, 7, 9, 11, 14 days during the consecutive 14 days of administration. The animals were sacrificed after the final IT administration. The lumbar segment of the spinal cord was removed for determination of the number of synapsis in the spinal dorsal horn by immuno-histochemistry in 4 animals in each group and observation of synaptic structure remodeling using electron microscope in another 4 animals in each group. Results Compared with group S, PWT was significantly decreased and PWL was shortened in the other 5 groups, and the number of synapsis was significantly increased and the synaptic structure was thickened in NP, NS, M and K groups (P ＜ 0.05). Compared with group NP,PWT was significantly increased and PWL was prolonged in M, K and MK groups, and the number of synapsis was significantly decreased and the thickness of synaptic structure was significantly reduced in group MK ( P ＜ 0.05).Compared with group M, PWT was significantly increased, PWL was prolonged, the number of synapsis was significantly decreased and the thickness of synaptic structure was significantly reduced in group MK ( P ＜ 0.05). Conclusion IT ketamine can inhibit the synaptic remodeling in the spinal dorsal horn during development of morphine tolerance in a rat model of NP. Key words: Ketamine; Morphine; Drug tolerance; Injections, spinal; Neuralgia; Spinal cord; Synapses; Neuronal plasticity

Checkpoint for Synapsis

The relationship between synapsis and recombination: two different views

The relationship of crossing over to chromosome synapsis in a short paracentric inversion.

An outline of the synapsis theory in crossing-over

A Study of Synizesis and Synapsis in Lilium superbum L.

Synapsis and Synizesis

A Study of Synapsis and Reduction