Objective Astragalus polysaccharide (APS) has promoting angiogenesis function. To explore the effects of APS collagen sponge on enhancing angiogenesis and collagen synthesis so as to provide evidence for the future tissue engineering appl ication as a kind of angiogenic scaffold. Methods APS collagen sponges were prepared by covalent binding with collagen polypeptides by using of crossl inking agents at the ratio of 1 ∶ 1 (W/W). Twenty 10-week-old SpragueDawley rats (10 males and 10 females, and weighing 200-250 g) were selected. Longitudinal incision was made at both sides of the back to form subcutaneous pockets. APS collagen sponges of 5 mm × 5 mm × 5 mm at size were implanted into the left pockets as the experimental group, collagen sponges without APS of the same size into the right pockets as the control group. The general conditions were observed after operation. At 3, 7, 14，and 21 days, 5 rats were sacrificed and the samples were harvested to count the number of microvessels, to measure the contents of the hydroxyprol ine (Hyp), and to detect the mRNA expressions of angiopoetin 1 (Ang1), matrix metalloproteinases 9 (MMP-9), and tissue inhibitors of metalloproteinases 1 (TIMP-1). Results All rats were al ive during experiment period. The number of microvessels increased gradually, and reached the peak at 14 days in 2 groups; the expermental group was significantly higher than the control group (P lt; 0.05). The contents of Hyp increased gradually in 2 groups, and the experimental group was significantly higher than the control group (P lt; 0.05). The mRNA expressions of Ang1 and MMP-9 in the experimental group were significantly higher than those in the control group at 3, 7, and 14 days (P lt; 0.05); the mRNA expression of TIMP-1 in the experimental group was significantly lower than that in the control group at 3 days and was significantly higher at 14 and 21 days (P lt; 0.05). Conclusion The APS collagen sponges can improve angiogenesis and collagen synthesis in wound heal ing by regulating the expressions of Ang1, MMP-9, and TIMP-1.
Objective To evaluate the effects of Shengji Yuhong collagen on promoting angiogenesis of the ischemia tissues and probe the possible mechanisms. Methods Forty-eight Wistar rats were divided by random method of paired into blank group， control group （collagen），and experimental group （Shengjiyuhong collagen）. After made the rats hind limb ischemia model， collagens with or without the extracts of Shengji Yuhong Gao were randomly paired implanted locally in hind limb ischemia tissues of rats in experimental group or control group. The samples of collagens and tissues about 0.5 cm large surrounding the collagen were explanted respectively on day 3，7， 14， and 28 for detected the hemog-lobin contents in colagen， microvascular counting by using CD34 immunohistochemical markers， and the expressions of HIF-1α mRNA and VEGF mRNA by using real-time fluorescent quantitative RT-PCR. The blood perfusion of the ischemic tissues at each time were determined by using laser speckle imaging system of Moor-FLPI. Results The results of Moor-FLPI showed that the obvious ischemia condition after model made， the blood perfusion was significantly lower than that before operation （P＜0.01）. On day 3 after operation it showed obvious congestion in the ischemic tissues， and from day 7 to day 14， it showed the ischemia state locally till day 28 after operation which showed improved situation of ischemic. Except for the day 3， the blood perfusion of experimental group were higher than those of blank group （P＜0.05）. There was no statistical significance between the blank group and control group （P＞0.05）. The blood perfusion on day 7 and day 14 after operation of experimental group were higher than those of control group （P＜0.05）. The hemoglobin contentsof each time point in the experimental group were higher than those in the control group （P＜0.01）. The microvascular counting on day 7 and day 14 in experimental group were higher than those of control group （P＜0.05）. The expressions of HIF-1α mRNA and VEGF mRNA at each time point of experimental group were higher than those of control group and blank group （P＜0.05）， and there was no significant differences between the control group and blank group （P＞0.05）. Conclusion The effects on promoting angiogenesis of rat hind limb ischemia tissues with Shengji Yuhong collagen may though inducing the expressions of HIF-1 α mRNA and VEGF mRNA locally.