BACKGROUND:Vascular endothelial growth factor and transforming growth factor play a crucial role in embryonic development, wound healing, inflammation, cancer, ischemic hypoxia and other physiological and pathological processes, and participate in the development and progression of brain damage. OBJECTIVE: To evaluate the differences in the expression of vascular endothelial growth factor and transforming growth factor-α during the early phase of cerebral aneurysm formation in rats. METHODS:Twenty-eight healthy Sprague-Dawley rats were randomized into three groups. Sham operation group (n=8): the left carotid artery bifurcation and bilateral renal artery were only exposed, without ligation, and rats were kiled that day. 15 days group (n=10) and 30 days group (n=10): the left common carotid artery, internal carotid artery, external carotid artery and bilateral renal artery were ligated, to establish aneurysm model, and rats were kiled at 15 and 30 days, respectively. The bilateral sides of the anterior cerebral artery/olfactory artery bifurcations were harvested and observed under light microscopy for pathological changes. Immunohistological staining was performed to detect the expression of vascular endothelial growth factor and transforming growth factor-α. RESULTS AND CONCLUSION:The results showed that, no aneurysm formed in the sham operation group and 15 days group. In the 30 days group, one saccular aneurysm and five early aneurysm-like changes were found in the right anterior cerebral artery/olfactory artery bifurcations. In the sham operation group and 15 days group, no vascular endothelial growth factor was expressed. In the 30 days group, the positive rate of vascular endothelial growth factor was up to 80%, indicating that vascular endothelial growth factor is possibly involved in the formation of aneurysm. Transforming growth factor-α expression in the sham operation group and 15 days group was more apparent than that in the 30 days group, indicating that transforming growth factor-α is damaged or secretion is reduced in this process, which was possibly related to the formation of aneurysm.

BACKGROUND:Adipose-derived stem cells are easily col ected and abundantly cultured, which can proliferate rapidly when being cultured in vitro. With multi-directional differentiation potential, adipose-derived stem cells are expected as seed cells for tissue engineering.
OBJECTIVE:To isolate, culture and identify of adipose-derived stem cells from Sprague-Dawley rats in vitro.
METHODS:The subcutaneous adipose tissue was obtained from the iliac region of rats under the aseptic condition, and then was digested with 0.075%type Ⅰ col agenase and cultured in vitro. The morphology and proliferation characteristics of the cells were observed under an inverted phase contrast microscope. The third passage was put into gauge for growth curve by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and the cells were also identified by CD44, a stem cellmarker, with immunofluorescence staining. Adipose-derived stem cells were induced and differentiated into adipocytes in Dulbecco’s modified Eagle’s medium/Ham’s nutrient mixture F-12 containing 10%fetal bovine serum, dexamethasone and insulin, and then the cells were identified with oil red“O”staining. Adipose-derived stem cells were induced and differentiated into neural cells, and then the cells were identified with immunohistochemical staining.
RESULTS AND CONCLUSION:The growth curve of adipose-derived stem cells was opposite-like“S”shape, and it strongly expressed CD44 that can designate a stem cell. The passage cells were exposed to a defined medium for adipocyte differentiation, and then could be stained with oil red. After being induced and differentiated into nerve cells, the cells expressed neuron-specific enolase. The adipose-derived stem cells of Sprague-Dawley rats are characterized by easy isolation, culture and proliferation in vitro, expressing related phenotypes of mesenchymal stem cells, as wel as induction and differentiation under certain conditions.

BACKGROUND:Matrix protein is an essential component of the vascular wal , provides a necessary frame for the integrity of the vessel wal and physiological function of vascular wal cel s, and regulates cel s and smooth muscle. OBJECTIVE:To construct rat model of early aneurysm, and to evaluate differences in the expression of matrix structural proteins during cerebral aneurysm formation. METHODS:Twenty-eight healthy male Sprague-Dawley rats were randomized into control group (n=8) and model group (n=20). Aneurysm model was established by ligation of the left common carotid artery and right renal artery-induced hypertension in the model group. In the control group, only the left carotid artery bifurcation and bilateral carotid were exposed in rats. Rats in the model group were sacrificed at 15 and 30 days after model establishment. Right anterior cerebral artery in rats and olfactory artery bifurcation received immunohistochemical staining. The expressions of fibronectin,α-smooth muscle actin and col agen III were analyzed. RESULTS AND CONCLUSION:Compared with the control group, no significant difference in fibronectin expression was detected in right anterior cerebral artery and olfactory artery bifurcation in rats of the model group at 30 days after model establishment (P>0.05). However,α-smooth muscle actin and col agen III expressions were significantly reduced (P<0.05). These data confirmed that expression of structural proteins had differences and dynamic changes during early aneurysm formation in rats. Degradation of matrix structural protein in cerebral artery may be one of the key mechanism of aneurysm formation.