Effect of different therapies of Chinese medicine on the expressions of c-Fos and c-Jun proteins in hippocampus of rats with post-stroke depression

BACKGROUND ： c-fos and c-jun, the important immediate early genes （IEG）, are regarded as the markers for the location and function of neuronal activity, as well as the third signal messengers, they couple the stress stimulation and the gene expression in neuron, and hippocampus is involved in the process of signal transmission after stress stimulation induced depression. OBJECTIVE： To observe the therapeutic effects of Bushen Yiqi （tonifying kidney to benefit qi）, Huoxue Huayu （promoting blood circulation to dissipate blood stasis） and Ditan Kaiqiao （eliminating phlegm for resuscitation） on the expressions of c-Fos and c-Jun proteins in hippocampus and spontaneous behaviors of rats with post-stroke depression （PSD）, and compare the results with those of fluoxetine, which is known to have definite effect on depression. DESIGN： A randomized controlled tna SETTING ： Zhejiang College of Traditional Chinese Medicine MATERIALS ： The trial was completed in Zhejiang College of Traditional Chinese Medicine from January to July in 2003. Fifty-six healthy adult Wistar male rats of clean grade, weighing （250±50） g, were randomly divided into 7 groups with 8 rats in each group： control group, model group, forced swimming group, Bushen Yiqi group; Huoxue Huayu, Ditan Kaiqiao group and fluoxetine group. The Bushen Yiqi Tang contained Renshen, Huangqi, Heshouwu, Gouqi, Shudi, etc., crude drugs 1 800 g/L. The Huoxue Huayu Tang contained Danshen, Chuanxiong, Chishao, Yujin, etc., crude drugs 3 600 g/L. The Ditan Kaiqiao Tang contained Banxia, Danxing, Changpu, Yuanzhi, etc., crude drug 1 000 g/b METHODS： ① Except the control group and forced swimming group, rats in the other groups were made into PSD models by deligating the bilateral common carotid artedes permanently. ② Rats in the control group, model group and forced swimming group were intragastncally perfused by saline （3 mL for each time）; those in the Bushen Yiqi group, Huoxue Huayu, Ditan Kaiqiao group and fluoxetine group were intragastncally perfused with Bushen Yiqi Tang （18 g/kg）, Huoxue Huayu Tang （9 g/kg）, Ditan Kaiqiao Tang （9 g/kg） and fluoxetine （2.5 mg/kg） respectively, once a day. ③ At 55 days after model establishment, rats in the forced swimming group were managed according to the Porsolt＇s method. They were placed in water for 15 minutes, and then taken out and dned, no moving-time within 5 minutes was recorded at drying and 24 hours after drying. ④ Measurement of spontaneous behaviors： Except the forced swimming group, the spontaneous behaviors and activities （including horizontal and vertical movements） of rats were observed with the Open-Field method at 28, 42 and 56 days after administration in the other groups. ⑤ The expressions of c-Fos and coJun proteins in hippocampus were determined with the immunohistochemical method, the relative sectional area ratio and average objective gray value of c-Fos and c-Jun positive cells in hip- pocampus were measured with the computerized image analytical system. MAIN OUTCOME MEASURES： The spontaneous behaviors of rats, the relative sectional area ratio and average objective gray value of c-Fos and c-Jun positive cells in hippocampus were observed. RESULTS： Of the 56 rats, 1 died in the forced swimming group, and finally 55 rats were involved in the analysis of results. ① Results of spontaneous activities： At 28 days, the times of crossing movements were obviously fewer in the model group and fluoxetine group [（69.00±37.01）, （98.11 ±36.68） times/3 minutes] than in the control group [（128.44±16.85） times/3 minutes, P 〈 0.01, 0.05], but those in the Bushen Yiqi group, Huoxue Quyu group and Ditan Kaiqiao group had no obvious differences as compared with those in the control group （P 〉 0.05）. At 42 and 56 days, the times of crossing movements were obviously more in the Bushen Yiqi group, Huoxue Quyu group and Ditan Kaiqiao group [（106.44±31.24）, （117.20±23.95）, （134.80±28.18）, （136.36±40.95） times/3 minutes; （117.33±35.91）, （129.60 ±23.78）, （131.90 ±26.81）, （136.09±28.34） times/3 minutes] than in the model group [（64.00±17.51）, （72.86±20.68） times/3 minutes, P 〈 0.01]. The times of rearing movements had no obvious differences among the groups for the three times （P 〉 0.05）. ② The no moving-time within 5 minutes 24 hours after drying was obviously longer than that at drying in the forced swimming group. ③ The average objective gray values of c-Fos positive cells were not obviously different in the Bushen Yiqi group and Ditan Kaiqiao group from the control group （P 〉 0.05）, but lower in the model group than in the control group （69.84±9.82, 75.78±5.89, P 〈 0.01）, and higher in the forced swimming group than in the control group （85.97±10.99, P 〈 0.01）; all higher in the fluoxetine group, Bushen Yiqi group, Huoxue Quyu group and Ditan Kaiqiao group than in the model group （81.27±10.73, 74.04±8.34, 83.29±9.89, 70.14±4.92, P 〈 0.05-0.01）. The average objective gray values of c-Jun positive cells were obviously lower in the Bushen Yiqi group than in the control group （68.11 ±6.89, 79.58±5.86, P 〈 0.01）, but all higher in the other groups than in the control group （84.68±7.15, 81.34 ±8.36, 97.51±10.55, 85.68±9.25, 86.19±10.98, P 〈 0.05-0.01）; Those were obviously higher in the fluoxetine group, Huoxue Quyu group and Ditan Kaiqiao group than in the model group （P 〈 0.05-0.01 ）, lower in the Bushen Yiqi group than in the model group （P 〈 0.05）, all obviously lower in the Bushen Yiqi group, Huoxue Quyu group and Ditan Kaiqiao group than in the fluoxetine group （P 〈 0.01）. The relative sectional area ratios of c-Fos and c-Jun positive cells had no obvious differences among the groups （P 〉 0.05）. CONCLUSION ： The methods of Bushen Yiqi, Huoxue Quyu and Ditan Kaiqiao can effectively treat PSD in rats, and the results were equivalent with those of fluoxetine, the actions of the above-mentioned drugs may correlated with their regulation to c-Fos and c-Jun expressions in hippocampus. PSD animal models can be successfully established by both permanent deligation of bilateral common carotid arteries and forced swimming, and the models induced by the former has similar basic cerebrovascular lesions as human stroke in clinic.

Developmental Lead Exposure Alters the Distribution of Protein Kinase C Activity in the Rat Hippocampus

Chronic low-level lead (Pb) exposure in children is known to cause a deficit in learning and memory. In vitro studies have demonstrated that Pb altered protein kinase C (PKC) activityt Especially, hippocampal PKC has been correlated with performance in several learning tasks. The effects of Pb exposure on hippocampal PKC were investigated during development at various postnatal ages: postnatal day (PN) 7, 14, 28, and 56. Two-tenth % Pb acetate was administered to pregnant and lactating dams and then administered to weanling rats in drinking water. PKC activity was measured in both membrane and cytosolic fractions from the hippocampi of the controls and Pb-exposed animals. Pb-induced increase in PKC activity in the cytosolic fraction was obsereved in the PN56 rats. In contrast, PKC activity was decreased by Pb at PN7 in the membrane fraction. Furthermore, a significant decrease in the ratio of membrane to cytosolic PKC activity which is representative of PKC distribution was observed in the PN28 and PN56 Pb-exposed rats relative to the same-age controls. This study indicates that chronic Pb exposure during development influences hippocampal PKC activity and distribution. These changes may be involved in the subclinical neurotoxicity of chronic Pb exposure in young children.

Toxic effect of acrylamide on the development of hippocampal neurons of weaning rats

Although numerous studies have examined the neurotoxicity of acrylamide in adult animals,the effects on neuronal development in the embryonic and lactational periods are largely unknown.Thus,we examined the toxicity of acrylamide on neuronal development in the hippocampus of fetal rats during pregnancy.Sprague-Dawley rats were mated with male rats at a 1：1 ratio.Rats were administered 0,5,10 or 20 mg/kg acrylamide intragastrically from embryonic days 6–21.The gait scores were examined in pregnant rats in each group to analyze maternal toxicity.Eight weaning rats from each group were also euthanized on postnatal day 21 for follow-up studies.Nissl staining was used to observe histological change in the hippocampus.Immunohistochemistry was conducted to observe the condition of neurites,including dendrites and axons.Western blot assay was used to measure the expression levels of the specific nerve axon membrane protein,growth associated protein 43,and the presynaptic vesicle membrane specific protein,synaptophysin.The gait scores of gravid rats significantly increased,suggesting that acrylamide induced maternal motor dysfunction.The number of neurons,as well as expression of growth associated protein 43 and synaptophysin,was reduced with increasing acrylamide dose in postnatal day 21 weaning rats.These data suggest that acrylamide exerts dose-dependent toxic effects on the growth and development of hippocampal neurons of weaning rats.

Non-viral liposome-mediated transfer of brain-derived neurotrophic factor across the blood-brain barrier

Brain-derived neurotrophic factor（BDNF） plays an important role in the repair of central nervous system injury,but cannot directly traverse the blood-brain barrier.Liposomes are a new type of non-viral vector,able to carry macromolecules across the blood-brain barrier and into the brain.Here,we investigate whether BDNF could be transported across the blood-brain barrier by tail-vein injection of liposomes conjugated to transferrin（Tf） and polyethylene glycol（PEG）,and carrying BDNF modified with cytomegalovirus promoter（pC MV） or glial fibrillary acidic protein promoter（p GFAP）（Tf-p CMV-BDNF-PEG and Tf-p GFAP-BDNF-PEG,respectively）.Both liposomes were able to traverse the blood-brain barrier,and BDNF was mainly expressed in the cerebral cortex.BDNF expression in the cerebral cortex was higher in the Tf-p GFAP-BDNF-PEG group than in the Tf-p CMV-BDNF-PEG group.This study demonstrates the successful construction of a non-virus targeted liposome,Tf-p GFAP-BDNF-PEG,which crosses the blood-brain barrier and is distributed in the cerebral cortex.Our work provides an experimental basis for BDNF-related targeted drug delivery in the brain.

Specific effects of c-Jun NH2-terminal kinaseinteracting protein 1 in neuronal axons

c-Jun NH2-terminal kinase（JNK）-interacting protein 3 plays an important role in brain-derived neurotrophic factor/tropomyosin-related kinase B（Trk B） anterograde axonal transport. It remains unclear whether JNK-interacting protein 1 mediates similar effects, or whether JNK-interacting protein 1 affects the regulation of Trk B anterograde axonal transport. In this study, we isolated rat embryonic hippocampus and cultured hippocampal neurons in vitro. Coimmunoprecipitation results demonstrated that JNK-interacting protein 1 formed Trk B complexes in vitro and in vivo. Immunocytochemistry results showed that when JNK-interacting protein 1 was highly expressed, the distribution of Trk B gradually increased in axon terminals. However, the distribution of Trk B reduced in axon terminals after knocking out JNK-interacting protein 1. In addition, there were differences in distribution of Trk B after JNK-interacting protein 1 was knocked out compared with not. However, knockout of JNK-interacting protein 1 did not affect the distribution of Trk B in dendrites. These findings confirm that JNK-interacting protein 1 can interact with Trk B in neuronal cells, and can regulate the transport of Trk B in axons, but not in dendrites.

Effects of Scutellaria baicalensis on neurogenesis in the hippocampal dentate gyrus and on spatial memory of adult rats

We investigated the effects of ethanol extracted Scutellaria baicalensis（EESB） on spatial memory function and neurogenesis in the hippocampal dentate gyrus.Adult Sprague-Dawley rats were orally administered 50,100,or 200 mg/kg of EESB for 6 successive days.The radial-arm maze test showed that 200 mg/kg of EESB improved the spatial memory of adult rats.Confocal microscopy results showed that 100 mg/kg of EESB increased the number of bromodeoxyuridine（BrdU）-and neuron-specific nuclear protein-positive cells in the granular cell layer,and that 100 and 200 mg/kg of EESB increased the number of BrdU-/neuron-specific nuclear protein-positive cells in the sub-granular zone.200 mg/kg of EESB increased the number of BrdU-/glial fibrillary acid protein-positive cells in the subgranular zone.These findings indicate that EESB can effectively promote neurogenesis in the hippocampal dentate gyrus and improve spatial memory function.