Altered expression of neurofilament 200 and amyloid-ß peptide (1-40) in a rat model of chronic cerebral hypoperfusion.

Chronic cerebral hypoperfusion (CCH) is damaging to white matter in the brain. So far few studies have investigated long-term axonal damage following CCH. The aim of this study was to investigate the involvement of neurofilament 200 (NF200) and amyloid-ß (1-40) [Aß (1-40)] in the pathological mechanism for neuronal damage, and to quantify changes in their expression over time in a rat model of CCH. A rat model of CCH was established using partial bilateral ligation of the common carotid arteries. The extent of stenosis was verified by measuring the changes in cerebral blood flow after surgery. Histology was used to assess hippocampal neuronal pathology, and immunohistochemistry was used to quantify the expression of NF200 and Aß (1-40) at 2, 4, and 12 weeks after surgery. The cerebral blood flow reduced to 33.89 ± 5.48 % at 2 weeks, 36.83 ± 4.63 % at 4 weeks and 51.44 ± 4.90 % at 12 weeks. Immunofluorescence staining of neuronal perikarya sections revealed a marked decrease in the population of surviving pyramidal cells in the hippocampal CA1 region, a significant up-regulation in the expression of Aß (1-40), and a significant reduction in the expression of NF200 following CCH surgery. Moreover, this trend was increasingly obvious over time. Our data demonstrate that CCH leads to axonal damage over time. We also confirmed that the expression of Aß (1-40) and NF200 may be useful biomarkers of axonal damage following CCH.

A study of the ultrasound-targeted microbubble destruction based triplex-forming oligodexinucleotide delivery system to inhibit tissue factor expression.

The efficiency of cellular uptake of triplex­forming oligodexinucleotides (TFO), and the inhibition of tissue factor (TF) is low. The aim of the present study was to improve the absorption of TFO, and increase the inhibition of TF induced by shear stress both in vitro and in vivo, by using an ultrasound­targeted microbubble destruction (UTMD)­based delivery system. TFO­conjugated lipid ultrasonic microbubbles (TFO­M) were first constructed and characterised. The absorption of TFO was observed by a fluorescence­based method, and the inhibition of TF by immunofluorescence and quantitative polymerase chain reaction. ECV304 human umbilical vein endothelial cells were subjected to fluid shear stress for 6 h after treatment with TFO conjugated lipid ultrasonic microbubbles without sonication (TFO­M group); TFO alone; TFO conjugated lipid ultrasonic microbubbles, plus immediate sonication (TFO+U group and TFO­M+U group); or mock treated with 0.9% NaCl only (SSRE group). The in vivo experiments were established in a similar manner to the in vitro experiments, except that TFO or TFO­M was injected into rats through the tail vein. Six hours after the preparation of a carotid stenosis model, the rats were humanely sacrificed. The transfection efficiency of TFO in the TFO­M+U group was higher as compared with the TFO­M and TFO+U group (P<0.01). The protein and mRNA expression of TF in the TFO­M+U group was significantly decreased both in vitro and in vivo (P<0.01), as compared with the TFO­M, TFO+U and SSRE groups. The UTMD­based TFO delivery system promoted the -absorption of TFO and the inhibition of TF, and was therefore considered to be favorable for preventing thrombosis induced by shear stress.