Effects Of Compound Tablet Of Red Sage Root On The Expression Of PDGF-B And VEGF During Chronic Cerebral Ischemia In Brain Of Rat

Chronic cerebral ischemia refer to the insufficiency of brain blood perfusion for a long time duing to various kinds of reason. It brings out histopathological and biochemical changes in brain ,which is a common pathological way in the period of many disease such as vascular dementia, Binswanger disease, Alzheimer disease. With the increasing of senile population in our country, prevention and therapy diseases mainly from chronic cerebrovascular insufficiency is increasingly important. De la Torre made the rat model of permanent bilateral common carotid artery occlusion(2VO) firstly in 1992. This model can decrease the cerebral blood flow even after several months, but the cerebral blood flow was not stop in any brain section because of the Willis loop of rat is developing very well. Tanka et al considered 2VO1~3 week is acute stage. It enter chronic stage after 3 weeks. Platelet-derived growth factor(PDGF) is a cell's factor which was found in 1974, and almost all neuron can express PDGF in central neural system(CNS). It is important in the repair of the damage of brain ischemia. Vascular endothelial growth factor(VEGF) is a sort of growth factor with multiple function, which can be secreted in many cell such as brain, kidney, liver, spleen, lung, bone et al. Its main functions involve increasing the blood vessel penetrating, promoting the growth of new capillary, suppressing the nerve cell to wither and die and so on, so it can play an important role in the course of repairing and compensation in chronic cerebral ischemia. Compound tablet of red sage root was used in cardiovascular and cerebrovascular diseases extensively, but there are few animal experiment about chronic cerebral ischemia. The experiment research the protective effect of compound tablet of red sage root to chronic cerebralischemia by observing superminor structure of neuron, PDGF-B and VEGF to supportthe prevention and therapy senile diseases with compound tablet of red sage root.Objective To observe the expressions and changes of PDGF-B and VEGF in brain of chronic cerebral ischemia rat. To investigate the mechanism of traditional Chinese medicine Compound Tablet of Red Sage Root on chronic cerebral ischemia.Subject and Methods (1)Animals and grouping: Selected 30 health SD female rats and divided into 3 groups randomly, 10 rats each group. Group A: sham-operation group (sham-operation plus distilled water); Group B: only hypoperfusion (hypoperfusion plus distilled water); group C: hypoperfusion and treatment (hypoperfusion plus compound tablet of red sage root plus distilled water). Group A and Group B swallowed distilled water 2ml, groups C swallowed the same amount of compound tablet of red sage root (0.75g/kg) disolved by distilled water. All the rats were raised in a usual way for 8 weeks.(2)The preparation of model: Rats underwent permanent bilateral occlusion of the common carotid arteries (2VO) in groups B and C. Bilateral common carotid arteries were only isolated but not ligated in groups A.(3) The sample collected and the index measured: The rats used to immunohistochemical observed were shot saline in brain arties then shot with 4% polyformaldehyde solution to be fixed, sacrificed by decapitation, the brain tissue was removed, embed in paraffin and made immunohitochemical sections(4um thick).Using HE staining and immuniohistochemical method, the number of PDGF-positive and VEGF-positive cells were detected. After the rats were decapitated. Hippocampus (1×1× 2mm3)of the rats used to be observed were taken out, then put into solution of 4% glutaral, after a series of treatments, bisected them to 50nm thick, observed them under 80 KV H-7500 electron microscope.(4)Statistical analysis: Data are shown as means ±S.D. Statistical data was analysized by SPSS 10.0. The difference of every two groups was compared with one-way analysis of variance and LSD method. The level of significance was set at a=0.05.Results: (1) All the rats were in low spirits, reacted slowly, ate little after operation. The next day, sham groups recovered in spirits, reacted quickly and ate more, but hypoperfusion groups improved insignificantly. After a week, they were almost in usual spirits, reacted and ate almost as usual.(2) The results of pathological section with HE staining: Group A has not found obvious pathology changes. Group B can be seen a large amount of degenerative or necrosic neuron. The degenerative or necrosic neuron were fewer than that of Group B.(3) PDGF-B immunohistochemistry staining: The score of PDGF-B positive cells at hippocampus CAl of every group: group A: 2.10±0.23; group B:3.85±0.43; group c:6.08±0.83.The difference between every two groups is significant (P<0.01). The score of PDGF-B positive cells at cortex of every group: group A: 1.60±0.18;group B: 3.30±0.36; group c: 5.23±0.49/The difference between every two groups is significant (p<0.01).(4) VEGF immunohistochemistry staining: The score of VEGF positive cells at hippocampus CAl of every group: group A: 2.38±0.32; group B: 3.73±0.54; group c: 6.83±0.85.The difference between every two groups is significant (P<0,01). The score of PDGF-B positive cells at cortex of every group: group A: 2.10±0.28; group B: 3.65±0.36; group c: 6.33±0.44.The difference between every two groups is significant (P<0.01).(5)The results of Electron microscope: To observation by transmission Electron microscope (HITACHI H-7500,80v),Group B: the heigh hydroncus around the capillary, the high hydroncus of neuron cytoplasm, the reduce of cell devices, the disorder arranged of mitochondria ridges and dispear of mitochondria ridges can be seen in major neuron .It is obvious that the interval of synapes expand or merge partly. The pathology changes of Group C were fewer than Group B. The membranes of synapses in Group C are insignificantly swollen.Conclusion: (1) Obvious degeneration and necrosis were seen in many neurons after 2VO 8 weeks. Cell organelle were damaged when observed by Electron microscope. It indicated that continuous chronic cerebral ischemia will damage brain cells irreversible.(2)After 2VO 8 weeks, the expression of PDGF-B and VEGF increased obviously.lt indicate that the body can increase the level of PDGF-B and VEGF in brain cell of chronic cerebral ischemia rats, in order to play its function of nerve protecting, promoting new capillary and improving brain circulation.(3)The expression of PDGF-B and VEGF in Group C were more than Group B, and the damages of neuron and capillary were milder than Group B, It indicate that compound tablet of red sage root can increase the expression of PDGF-B and VEGF and it can play an important role in the chronic cerebral ischemia.