In order to investigate the neurotoxicity of lipopolysaccharide (LPS) on the dopaminergic neurons of substantia nigra and the pathogenesis of Parkinson disease. LPS was stereotaxically infused into substantia nigra (SN). At different dosages and different time points with 5 μg LPS, the damage of the dopaminergic neurons in SN was observed by using tyrosine-hydroxylase (TH) immunohistochemical staining. The results showed that 14 days after injection of 0.1 μg to 10 μg LPS into the rat SN, TH-positive (TH+) neurons in the SN were decreased by 5%, 15%, 20%, 45%, 96% and 99% respectively. After injection of 5 μg LPS, as compared with the control groups, TH+ neurons began to decrease at 3rd day and obviously decrease at 14th day, only 5% of total cells, and almost disappeared 30 days later. The results suggested that LPS could induce the degeneration of dopaminergic neurons in the SN in a dose- and time-dependent manner.
To examine the role of nitric oxide in the β-adrenergic vasodilation of epicardial coronary arteries in dogs, 12 dogs were instrumented for measurement of left anterior descending coronary artery diameter by transthoracic echocardiography before and after dobutamine (5 μg/kg/min IV) with and without intracoronary infusion of NG-monomethyl-L-arginine (L-NMMA) (1 mg/kg). In all 12 dogs, the diameter of left anterior descending coronary artery increased significantly from 2. 35±0.25 mm to 2.59±0.24 mm (P<0.001) after dobutamine administration. In 6 of the 12 dogs, the percent change in left anterior descending coronary artery diameter induced by dobutamine decreased significantly from 12.5%±8.6% to −1.5%±5.4% (P<0.05) after the administration of intracoronary L-NMMA (1 mg/kg for 5 min) to block nitric oxide synthesis from L-arginine. The study demonstrated that nitric oxide formation contributes to the β-adrenergic dilatory response of epicardial coronary arteries to dobutamine in dogs.
In order to study the chondrogenic phenotype differentiation of adult sheep bone marrow-derived mesenchymal stem cells (MSCs) in a defined medium as potential seed cells for cartilage tissue engineering, MSCs were isolated by density centrifugation with Percoll solution from bone marrow aspirated from sheep iliac crest. The third passage of MSCs were induced with H-DMEM containing TGF-β3. IGF I. Dexamethasone and VitC. The shape and ultrastructure of cells were observed, toluidine blue stain for GAG and immunohistochemistry for type II collagen were applied for chondrogenic phenotype identification. After 14 days of induction, MSCs changed from a spindle-like appearance to a polynal shape, a large amount of endoplasmic reticulum. Golgi complex and mitochondria were observed, and the differentiation of MSCs chondrogenic phenotype was verified by positive staining of toluidine blue and immunohistochemistry. MSCs derived from bone marrow can differentiate to chondrogenic phenotype when inducedin vitro and can be used as optimal seed cells for cartilage tissue engineering.
To investigate the expression of vasoactive intestinal peptide (VIP) and substance P (SP) in the cochlea of spontaneously hypertensive rat (SHR), and to assess the function of VIP and SP in the cochlea following the damage of hypertension, hearing thresholds of ABR were observed and the fixative (4% paraformaldehyde) was pumped through the circulatory system. Adult Wistar rats (3 months,n=20) served as the control group and SHRs (3 months,n=20) as the hypertension group. Bullas were taken out and cochleas were irrigatedin vitro with the same fixative. The number of base turns spiral ganglions in the sections was counted. The expression of VIP and SP were detected by SABC method and the images of the sections were analyzed. The number of base turns spiral ganglsons in the hypertension group was significantly less than in the normal group (P<0.01). VIP and SP were expressed in the spiral ganglion cytoplasma and stria vascularis of the two groups. There were no significant difference in the expression of VIP and SP in spiral ganglion cytoplasma (P>0.05) between the two groups. However, in stria vascularis the expression of VIP in the hypertension group was higher than in the normal group (P<0.05), and no significant difference in SP was found between the two groups. It was suggested that VIP not only contributed to the regulation of the cochlea microcirculation, but also made the neurotransmitter in the pathway of the auditory system. However, SP made only the neurotransmitter in the pathway of the auditory system.
Whether tranilast had antagonistic effect on proliferation inhibition and collagen synthesis promotion induced by TGF-\sB2 in cultured human trabecular meshwork cells was investigated. Suspension of 1×104 cultured human trabecular meshwork cells of 3–5 passage was distributed in each well of a 96-well disk and divided into control group and experimental group. After 24 h, 0 μg/ml (control), 12.5 μg/ml, 25 μg/ml, 50μg/ml tranilast with 3.2 ng/ml TGF-\sB2 were added into the incubation medium. Another 24 h later, proliferation and collagen synthesis in cultured human trabecular meshwork cells were examined respectively by using tetrazolium-based semiautomated colormetric (MTT) assay and3H-proline incorporation with liquid scintillation technique. The results showed absorbance (A) values of the experimental groups were 0.9036±0.3017, 1.1361±0.1352, 1.2457±0.1524 according to the different concentrations of tranilast, and 0.8956±0.1903 of the control group. In comparison with the control group, 25 μg/ml (q=3.23,P<0.05), 50 μg/ml (q′=4.70,P<0.01) tranilast significantly antagonized the decrease of theA values induced by TGF-\sB2 in the cultured human trabecular meshowrk cells. In comparison with the control group [817.37±124.21 cpm/104 cells], 12.5 μg/ml (620.33±80.46 cpm/104 cells,q′=4.26,P<0.05), 25 μg/ml (59.4.58±88.13 cpm/104 cells,q′=4.81,P<0.01), 50 μg/ml (418.64±67.90 cpm/104 cells,q′=8.62,P<0.01) tranilast significantly inhibited the incorporation of3H-proline into the cultured human trabecular meshwork cells promoted by TGF-\sB2 in a dose-dependent manner. It was concluded that tranilast had the antagonistic effect on the proliferation inhibition and collagen synthesis promotion induced by TGF-\sB2 in the cultured human trabecular meshwork cells.