BACKGROUND: In China, this laboratory is the first one to report such researches, confirming that strong αo-immunoreactive (IR) appears in the substantia gelatinosa (SG) of spinal cord and lateral spinal nucleus which is similar to the distribution of certain neuropeptides that participate in sensory regulation, which suggests that guanine nucleotide binding protein (G protein) may be related to primary afferent informational transfer. OBJECTIVE: To observe the change of αo-IR in gelatinous substance by the method of transection of unilateral spinal dorsal roots.DESIGN: A randomized controlled experiment on animals.SETTING: Staff Room of Neurobiology, Tongji Medical College, Huazhong University of Science and Technology.MATERIALS: The experiment was conducted at the Staff Room of Neurobiology, Tongji Medical College, Huazhong University of Science and Technology from December 1995 to December 1996. Fifteen healthy adult SD rats were selected and divided into 3 groups: ①normal group with five rats (not dealt with any disposal), ②transected dorsal root group with 10 rats (right side) and ③control group (non-transected left sidedness as control).METHODS: Right lumbar 1-3 spinal neural dorsal roots were cut off under the anesthesia of 100 g/L chloral hydrate (300 mg/kg)through intraperitoneal injection in rats, living for 48-60 hours after operation. The subunit αo of guanine nucleotide-binding protein (rabbit polyclonal antiserum) was demonstrated in the αo-IR of rat spinal cord by immunohisto chemical methods. G protein was oriented, and its change was observed after transection ofneural dorsal roots MAIN OUTCOME MEASURES: ①The αo-IR of Ⅰ to Ⅲ of the dorsal horn and lateral spinal nucleus of the normal rats and control rats. ②The αo-IR of Ⅰ to Ⅲ of the dorsal horn and lateral spinal nucleus of rats in the transected dorsal root group. RESULTS: Data of a total of 15 rats were involved in the result analysis. ①In the normal group and control group, intense αo-IR was presented in rexed lamina ( Ⅰ to Ⅲ ) of the dorsal horn of rats, and the highest αo-IR in second lamina (SG). Lateral spinal nucleus of rat revealed higher density of αo-IR containing fiber networks. Following unilateral transection of dorsal roots in SG, αo-IR was markedly decreased. ②Quantitative analysis of absorbance (A) of αo-IR, it was (0.847±0.081) in the inside of the control group, (0.633±0.073)(t=5.71 ,P ＜ 0.001 ) in the inside of transected dorsal root group. It was (0.823±0.089) in the middle area of the control group,(0.660 4±0.074)(t=6.90,P ＜ 0.001 ) in the middle area of the transected dorsal root group. It was (0.915±0.090) in the lumbar region of the control group, and (0.656±0.077)(t=10.31 ,P ＜ 0.001 ) in the lumbar region of the transected dorsal root group. Average value of the control group was (0.852±0.084), and average value of the transected dorsal root group was (0.639±0.078)(t=10.23 ,P ＜ 0.001 ).CONCLUSION: Part of G protein of end-brush neurons related with the primary afferent noxious stimulation in SG derives from primary sensory neurons, which maybe join the adjustment of primary sensory transfer.

Immunoreactivity of neurotensin(NT) and substance P (SP) were studied by means of PAP method with simultaneous immunocytochemical double staining on the same sections using diaminobenzidine (DAB) for SP and benzidinc dihydrochloride(BDHC) for NT as the chromogens for light and electron microscopy in dorsal horn of spinal cord of rat treated with colchicinc. In our hands the reaction products of DAB and BDHC is quite discernible, under LM the former is brown and later is blue; under EM DAB reaction product is homogeneous and diffuse electron opaque while BDHC reaction product is patch electron opaque, it is a new but simpler approach to demonstrate two antigens simultaneously in the same ultrathin section. It would be conformable further to the studies of morphological and functional relationships between different kinds of neurons. The results showed that NT-like immunoreactive (NT-LI) perikarya were mainly located in lamina Ⅱi and out layer of lamina Ⅲ and NT-LI terminals were mainly located in laminae Ⅰ-Ⅲ. Under EM the NT-LI axon terminals may synapse with the unlabeled axon or unlabeled dendrites. SP-like immunoreactive (SP-LI) perikarya were mainly located in lamina Ⅱ. The density of SP-LI terminals were higher in laminae Ⅰ-Ⅱ, while axo (SP)-axonic (SP), axo (SP)-somatic (SP) synapses were identified with EM. In double labelling sections, furthermore under EM, it was found that NT-LI axon terminal (BDHC patch like electron opaque reaction products)can synapse or contact with SP-LI axon (DAB diffuse electron opaque reaction products). Our results suggested that NT-and SP-containing neurons and terminals in dorsal horn might participate in regulating process of primary sensory transmission.

The subunit ?_0 of guanine nucleotide- binding protein, in the areas of rat brain and spinal cord was localized by immunohistochemical methods. It was found that in the rat brain, specific ?_0-like immunoreactivity(?_0-Li) displayed regional heterogeneity, a high density of ?_0-Li revealed in neuropil, and somatic membranes as well as the neuronal processes.Most intense ?_0-Li can be seen in substantia nigra(pars reticulata), interpcduncular nucleus, habenulo-interpeduncular tract, strata oriens and radiatum of the hippocampus, and substantia gelatinosa of the spinal cord. There are also areas of moderate staining ie: the molecular layer of cerebral and cerebellar cortex, habenula, caudate-putamen complexes, the midline nuclei of thalamus and hypothalamus, periaqueductal grey, grey layers of superior colliculus, the olivo-cerebellar tract and the spinal tract of the trigeminal nerve as well. By contrast, the immunoreactvity of ?_0 in septal nuclei, globus pallidus, red nucleus, and the regions adjacent canalis centralis of the spinal cord showed much weaker. In addition, on the membranes and the processes of the neuronal cell bodies in the periaqueductal grey, substantia nigra, reticular formation, medial geniculate body and the nucleus of the trapezoid body were ?_0-Li positive.The results of AChE staining revealed that the AChE-positivc nerve terminals was coinsident with the presence of ?_0-Li in the following regions. For instance: the molecular layer of cerebral cortex, hippocampus, spinal tract of the trigminal nerve, and substantia gelatinosa of the spinal cord, where both the ?_0-Li and the AChE activity were positive. It is suggested that ?_0 subunit of Go-protein in brain might play roles in membrane signal transduction, and might have some relationship with cholinergic nerve.

In order to prevent the teaching reform of organ system curriculum from fall of teaching quality, the teaching effect of organ system curriculum and subject curriculum system in teaching the basic knowledge of pathophysiology was compared. In organ system curriculum teaching, there was no difference between the grades of students in Batch 2011 and Batch 2012 who conformed to the teaching principle of "gradual improvement" and those of the students taught with subject curriculum system. On the contrary, the students of Batch 2013 and Batch 2014 with insufficient curriculum content integration had a decreasing trend or a significant reduction in the teaching effect of organ system curriculum compared with that of subject curriculum system. After the supplementary for curriculum knowledge was made, the teaching effect of the organ system was significantly improved, which was better than that of the subject curriculum system. In conclusion, we have summarized and reflected on the effectiveness of the teaching reform of organ system curriculum, once again proved that basic medical teaching must also follow the inherent law of medical education, which is the teaching principle of "gradual improvement."

OBJECTIVE To investigate the effects of lead exposure on the permeability,secretion and transportation function of blood-cerebro-spinal fluid barrier (BCB)of rats in order to provide the theo-rical basis for elucidating the mechanis m of lead induced neurotoxicity.MEHTODS 60 SPF SD rats were rando mly divided into 4 groups,including a control group and three doses lead exposed groups. Rat in the lead exposure groups were given drinking water containning 0.05%,0.1 % and 0.2% lead acetate (at dose of 80,160,320 mg·kg -1 )for 8 weeks.Laser scanning confocal microscopy was uti-lized to determine the lead content in seru m,cerebrospinal fluid (CSF)and choroid plexus sa mples. Morris maze was used to test learning and me mory.Fe moral artery perfusion of Evans blue (EB)and fluorescein sodiu m (NaFI)was performed to measure BCB permeability function.Confocal laser scan-ning was applied to detect junction adhesion molecule (JAM)and occludin protein expression in choroid plexus.ELISA was used to measure the concentration of transthyretin (TTR)and leptin in seru m and CSF.RESULTS The lead content in seru m,choroid plexus and CSF significantly increased,especially the lead level in CSF.Morris water maze data showed that escape latency of rat in lead acetate 160 and 320 mg·kg -1 group were 52 ±12,(89 ±19)s,respectively,longer than that of control group 〔(28 ±7)s, P<0.05〕.The ti mes across platform of rats in lead acetate 160 and 320 mg·kg -1 group were lower than that of control group(P <0.05).The NaFI content in CSF of rats in all lead acetate exposure groups were 0.94 ±0.09,1 .02 ±0.03 and (1 .08 ±0.18)mg·L -1 ,respectively,and were higher than those of control group〔(0.74 ±0.04)mg·L -1 〕;While the EB content in CSF of rat in lead acetate 160 and 320 mg·kg -1 group were higher than the control group(P <0.05),which indicated that lead acetate exposure at low dose can lead to the increase of permeability of BCB.Laser scanning confocal micro-scope i mages showed that the JAM protein expression of choroid plexus in lead acetate 160 and 320 mg·kg -1 group were 44.9% and 42.9% of the control group.Sa me decline was seen in terms of occludin expression.The TTR content of CSF of rats in lead acetate 80 mg·kg -1 group was (32.3 ± 1 1 .7)ng·g -1 protein,lower than that of the control group,and the difference was significant.This decline was also noted in lead acetate 160 and 320 mg·kg -1 group.The data of TTR in CSF suggested that the low dose lead acetate exposure can disrupt the BCB secretion function.The leptin levels in CSF of lead acetate 160 and 320 mg·kg -1 group were lower than that in the control group (P <0.05 ). CONCLUSION Lead exposure did disrupt the permeability,transportation and secretion function of BCB.Our data suggest that BCB dysfunction might be involved in the mechanis m of lead induced neurotoxicity.

OBJECTIVETo investigate the effects of nano-lead exposure on learning and memory and iron homeostasis in the brain of the offspring rats on postnatal day 21 (PND21) and postnatal day 42 (PND42).

METHODSTwenty adult pregnant female Sprague-Dawley rats were randomly divided into control group and nano-lead group. Rats in the nano-lead group were orally administrated 10 mg/kg nano-lead, while rats in the control group were administrated an equal volume of normal saline until PND21. On PND21, the offspring rats were weaned and given the same treatment as the pregnant rats until 42 days after birth. The learning and memory ability of offspring rats on PND21 and PND42 was evaluated by Morris water maze test. The hippocampus and cortex s amples of offspring rats on PND21 and PND42 were collected to determine iron and lead levels in the hippocampus and cortex by inductively coupled plasma-mass spectrometry. The distributions of iron in the hippocampus and cortex were observed by Perl's iron staining. The expression levels of ferritin, ferroportin 1 (FPN1), hephaestin (HP), and ceruloplasmin (CP) were measured by enzyme-linked immunosorbent assay.

RESULTSAfter nano-lead exposure, the iron content in the cortex of offspring rats on PND21 and PND42 in the nano-lead group was significantly higher than those in the control group (32.63 ± 6.03 µg/g vs 27.04 ± 5.82 µg/g, P<0.05; 46.20 ±10.60 µg/g vs 36.61 ± 10.2µg/g, P<0.05). The iron content in the hippocampus of offspring rats on PND42 in the nano-lead group was significantly higher than that in the control group (56.9 ± 4.37µg/g vs 37.71 ± 6.92µg/g, P<0.05). The Perl's staining showed massive iron deposition in the cortex and hippocampus in the nano-lead group. FPNl level in the cotfex of offspring rats on PND21 in the nano-lead group was significantly lower than that in the control group (3.64 ± 0.23 ng/g vs 4.99 ± 0.95 ng/g, P<0.05). FPN1 level in the hippocampus of offspring rats on PND42 in the nano-lead group was significantly lower than that in the control group (2.28 ± 0.51 ng/g vs 3.69 ± 0.69 ng/g, P<0.05). The escape latencies of offspring rats on PND21 and PND42 in the nano-lead group were longer than those in the control group (15.54 ± 2.89 s vs 9.01 ± 4.66 s; 6.16 ± 1.42 s vs 4.26 ± 1.51 s). The numbers of platform crossings of offspring rats on PND21 and PND42 in the nano- lead group were significantly lower than those in the control group (7.77 ± 2.16 times vs 11.2 ± 1.61 times, P<0.05; 8.12 ± 1.51 times vs 13.0 ± 2.21 times, P<0.05).

ONCLUSIONn Nano-lead exposure can result in iron homeostasis disorders in the hippocampus and cortex of offspring rats and affect their learning and memory ability.

Animals ; Cerebral Cortex ; drug effects ; metabolism ; Female ; Hippocampus ; drug effects ; metabolism ; Homeostasis ; Iron ; metabolism ; Lead ; toxicity ; Learning ; drug effects ; Maternal Exposure ; adverse effects ; Memory ; drug effects ; Pregnancy ; Rats ; Rats, Sprague-Dawley

The effect of magnetic stimulation (MS) on sciatic nerve injury was observed. After sciatic nerve was crushed in 40 Sprague Dawley (SD) rats, one randomly selected group (group D) was subjected, from the 4th day post-operatively to 3 min of continuous 70% of maximum output of MS daily for 8 weeks. The other group (group E) served as a control group. The nerve regeneration and motor function recovery were evaluated by walking track analysis (sciatic function index, SFI; toe spreading reflex, TSR), electrophysiological, histological and acetylcholineesterase histochemistry. The SFI in the group D was greater than in the group E with the difference being statistically significant (P < 0.01). TSR reached its peak on the 4th day in the group D and on the 10th day in the group E respectively. The amplitude and velocity of MCAP and NCAP in the group D was greater than in the group E with the difference being statistically significant (P < 0.01), while the latency and duration of MCAP and NCAP in the group D were less than in the group E with the difference being also statistically significant (P < 0.01). Histological examination showed the mean axon count above the lesion for thick myelinated fibers (> 6.5 microns) in the group D was greater than in the control group with the difference being statistically significant (P < 0.01), while the mean axon count below the lesion for thick myelinated fibers was less than that in the group E with the difference being statistically significant (P < 0.01). The mean axon count above the lesion for thin myelinated fibers (2-6.5 microns) in the group D was greater than that in the group E with the difference being statistically significant (P < 0.05), while the mean axon count below the lesion for thin myelinated in the group D was greater than that in the group E with the difference being statistically significant (P < 0.01). Acetylcholine esterase examination showed that the MS could significantly increase the number of the motor neurons. There was no significant difference in the number of the motor neurons between the treatment side and the normal side (P > 0.05). It can be concluded that MS can enhance functional recovery and has a considerable effect in the treatment of the peripheral nerve injury.
Acetylcholinesterase/metabolism ; Electromagnetics ; Motor Neurons/physiology ; *Nerve Regeneration ; Random Allocation ; Rats, Sprague-Dawley ; Sciatic Nerve/*injuries ; Sciatic Nerve/*physiopathology ; Sciatic Neuropathy/rehabilitation

The influence of pulsed magnetic stimulation (MS) on the sciatic nerve injury was investigated. Thirty rats were divided into three groups equally: MS group (A), electric stimulation (ES) group (B) and the control group (C). The MS and ES were applied immediately after the first 10 min of the sciatic nerve crush. Sciatic function index (SFI), toe spreading reflex (TSR), muscular weight and volume were measured after the experiment. The TSR of in the groups A and B occurred at 4th day while in the control group it occurs at 10th day. There was statistically significant difference in SFI between groups A and B (P<0.01). The weight and volume of the gastrocnemius muscle were statistically greater in the groups A and B than in the control group (P<0.01). The effect of MS was similar to that of ES. It was suggested that the application of MS immediately after the nerve injury might have an important clinical value as it can accelerate functional recovery and prevent or minimize muscle atrophy. The technique is easily to operate, non-invasion, painless and permits tolerance of high intensity output to be used.

The influence of pulsed magnetic stimulation (MS) on the sciatic nerve injury was investigated. Thirty rats were divided into three groups equally: MS group (A), electric stimulation (ES) group (B) and the control group (C). The MS and ES were applied immediately after the first 10 min of the sciatic nerve crush. Sciatic function index (SFI), toe spreading reflex (TSR), muscular weight and volume were measured after the experiment. The TSR of in the groups A and B occurred at 4th day while in the control group it occurs at 10th day. There was statistically significant difference in SFI between groups A and B (P<0.01). The weight and volume of the gastrocnemius muscle were statistically greater in the groups A and B than in the control group (P<0.01). The effect of MS was similar to that of ES. It was suggested that the application of MS immediately after the nerve injury might have an important clinical value as it can accelerate functional recovery and prevent or minimize muscle atrophy. The technique is easily to operate, non-invasion, painless and permits tolerance of high intensity output to be used.

The effect of magnetic stimulation (MS) on sciatic nerve injury was observed. After sciatic nerve was crushed in 40 Sprague Dawley (SD) rats, one randomly selected group (group D) was subjected, from the 4th day post-operatively to 3 min of continuous 70% of maximum output of MS daily for 8 weeks. The other group (group E) served as a control group. The nerve regeneration and motor function recovery were evaluated by walking track analysis (sciatic function index, SFI; toe spreading reflex, TSR), electrophysiological, histological and acetylcholineesterase histochemistry. The SFI in the group D was greater than in the group E with the difference being statistically significant (P < 0.01). TSR reached its peak on the 4th day in the group D and on the 10th day in the group E respectively. The amplitude and velocity of MCAP and NCAP in the group D was greater than in the group E with the difference being statistically significant (P < 0.01), while the latency and duration of MCAP and NCAP in the group D were less than in the group E with the difference being also statistically significant (P < 0.01). Histological examination showed the mean axon count above the lesion for thick myelinated fibers (> 6.5 microns) in the group D was greater than in the control group with the difference being statistically significant (P < 0.01), while the mean axon count below the lesion for thick myelinated fibers was less than that in the group E with the difference being statistically significant (P < 0.01). The mean axon count above the lesion for thin myelinated fibers (2-6.5 microns) in the group D was greater than that in the group E with the difference being statistically significant (P < 0.05), while the mean axon count below the lesion for thin myelinated in the group D was greater than that in the group E with the difference being statistically significant (P < 0.01). Acetylcholine esterase examination showed that the MS could significantly increase the number of the motor neurons. There was no significant difference in the number of the motor neurons between the treatment side and the normal side (P > 0.05). It can be concluded that MS can enhance functional recovery and has a considerable effect in the treatment of the peripheral nerve injury.
Acetylcholinesterase ; metabolism ; Animals ; Electromagnetic Phenomena ; Motor Neurons ; physiology ; Nerve Regeneration ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve ; injuries ; physiopathology ; Sciatic Neuropathy ; rehabilitation