ABSTRACT
Abstract The leaves of Syringa oblata Lindl., Oleaceae, had been extensively used as a folk medicine to treat various infections, heal inflammations, icteric hepatitis and acute mastitis. The study was designed to evaluate the hepatoprotective activity of S. oblata leaves ethanol extract against CCl4-induced hepatotoxicity in primary hepatocytes and mice with the indicator of glutathione S-transferase alpha 1. The hepatoprotective effects of S. oblata leaves ethanol extract were evaluated on the basis of liver histopathology and biochemical parameters as well as hepatic oxidative stress markers. The results showed that CCl4 negatively modulated biochemical parameters and liver antioxidant activities. However, the use of S. oblata leaves ethanol extract restored altered-serum biochemical parameters and liver antioxidant activities in a dose-dependent manner. Importantly, the trends in S-transferase alpha 1 were similar to alanine aminotransferase and aspartate aminotransferase level, and S-transferase alpha 1 was suggested to be a marker for the evaluation of hepatoprotective activity of S. oblata leaves ethanol extract. Histopathological examination showed that CCl4 causes significant hepatic injury relative to control group. The above findings suggested that S. oblata leaves ethanol extract has hepatoprotective effects against CCl4-induced hepatic injury and S-transferase alpha 1 may be an indicator to evaluate the protective effects of S. oblata leaves ethanol extract.
ABSTRACT
In order to improve the surface properties of PLGA polymer for a better material/cell in-terface to modulate the cells behaviors, we prepared a novel three-block copolymer, PLGA-[ASP-PEG],and immobilized an RGD-containing peptide, Gly-Arg-Gly-Asp-Ser-Pro-Cys (GRGDSPC) on the sur-face of it. Transforming growth factor-131 (TGF-β1) was transfected into bone marrow stromal cells (MSCs) employed as seeded cells. Cell adhesion, spreading, proliferation and differentiation on this material were investigated. The results showed that the cell adhesive ratio on RGD-modified materials was higher than on un-modified materials (P<0.05). The extent of cell spreading was also wider on RGD-modified materials than on un-modified materials. Cell proliferation indices of transfected MSCs were increased as compared with the un-transfected MSCs (P<0.05). The ALP activities in the MSCs cultured with RGD-modified materials were higher than on un-modified materials after 14 days (P<0.05), and those in transfected MSCs were higher than in un-transfected MSCs (P<0.05). It was suggested that the combined use of RGD-modification and TGF-β gene transfection could improve the interaction of biomaterial and cells.
ABSTRACT
In this study, the bioactivity of a novel BMP2-derived oligopeptide P24 was investigated by using the model of rabbit femoral defect after loaded in the biodegradable poly (lactic acid / glycolic acid / asparagic acid-co-polyethylene glycol) (PLGA-[ASP-PEG]). A 1.5-cm unilateral segmental bone defect was created in the left femoral diaphysis in each of the 30 new zealand white rabbits.The defects of 18 legs filled with BMP2-derived peptide P24 combined with PLGA-[ASP-PEG]scaffold serves as the experimental group, and the defects in the rest 12 rabbits filled with(PLGA-[ASP-PEG]) without P24 as control group. The bone-repairing capability in the target region of the two group was grossly, radiologically, histopathologically and biomechanically evaluated 4, 8and 12 weeks after the operation. Our results showed that in each group, primary healing of incision was achieved in the two groups. Radiographically, in experimental group, defects were filled with induced callus within 8 weeks, and a cortical bone-like structure was observed in some animals at the12th week. According to the standardized stage of bone defect repair, 9 (64.28%) achieved grade-4healing. In contrast, little bone formation was seen in the defects even 12 weeks after the operation,and 5 (62.50%) had grade 0 healing in this group. Histologically, tissue engineering material was mostly absorbed and cartilage was found around implants in the experimental group at the 4th week;8 weeks after operation, the engineering material was completely absorbed, and formation of woven bone was observed and typical trabecular bone structure could be seen. In control group, 8 weeks after operation, the defect was filled with fibrous tissues, and no bone-like structure was observed. Statistical analysis showed very significant difference in biomechanical indicators between the two groups (P＜0.05). It is concluded that new oligopeptide P24 can induce excellent bone regeneration and promote bone repair.