[Expression and function of vascular endothelial growth factor and angiopoietins in rat brain after cerebral ischemia].

Abstract

OBJECTIVE:

To examine the temporal and spatial expression of vascular endothelial growth factor (VEGF) and angiopoietins (Ang) in rat brain after cerebral ischemia, and to elucidate the roles they played in angiogenesis and vascular permeability.

METHODS:

Rats were subjected to either middle cerebral artery occlusion (MCAO) or sham operation. Reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemistry were used to detect the expression of VEGF, Ang-1 and Ang-2 at different time points after ischemia. CD31 was used to label endothelial cells after MCAO. Vascular permeability was determined by Evans blue.

RESULTS:

VEGF was markedly increased at 2 h, had an initial peak at 12 h (0.7249 ± 0.1933, P < 0.01), and a second peak at 7 days (0.5264 ± 0.1519, P < 0.01). Ang-2 mRNA and protein significantly increased after MCAO, both of them peaked at 12 h (0.6747 ± 0.2416, P < 0.01; 1.1197 ± 0.1780, P < 0.01). In contrast, Ang-1 mRNA and protein gradually decreased after MCAO, respectively reaching a minimum at 3 d (0.3220 ± 0.1427, P < 0.01) and 1 d (0.1298 ± 0.0293, P < 0.01). Changes in the expression of these factors correlated with the progress of angiogenesis and vascular permeability. Evans blue test revealed that the vascular permeability gradually increased, and peaked at day 1 after ischemia [(6.219 ± 0.887) µg/g, P < 0.01].

CONCLUSION:

Dynamic temporal changes in VEGF, Ang-1 and Ang-2 expression stimulate the cerebral angiogenesis after focal cerebral ischemia.

• Authors: Li-kun Zan, Yue-jia Song, Guo-xin Teng, Heng Li, Wei Liu, Ying Jia, Min Zhou, Yu-lan Sun, Ji-ping Qi
• Journal: Zhonghua bing li xue za zhi = Chinese journal of pathology (Zhonghua Bing Li Xue Za Zhi) Vol. 40 Issue 12 Pg. 834-9 (Dec 2011) ISSN: 0529-5807 [Print] China
• PMID: 22336210 (Publication Type: English Abstract, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Angiopoietin-1
• Angiopoietin-2
• Angpt1 protein, rat
• RNA, Messenger
• Vascular Endothelial Growth Factor A
• vascular endothelial growth factor A, rat

Topics

• Angiopoietin-1 (genetics, metabolism)
• Angiopoietin-2 (genetics, metabolism)
• Animals
• Blotting, Western
• Capillary Permeability
• Immunohistochemistry
• Infarction, Middle Cerebral Artery (metabolism, pathology, physiopathology)
• Male
• Neovascularization, Physiologic
• RNA, Messenger (metabolism)
• Random Allocation
• Rats
• Rats, Sprague-Dawley
• Reverse Transcriptase Polymerase Chain Reaction
• Vascular Endothelial Growth Factor A (genetics, metabolism)