ABSTRACT
BACKGROUND: The thermo-sensitive composite hydrogels have gained increasing interest in bone regeneration domain due to their biomimetic extracellular matrix (ECM) structure, good biocompatibility, minimal invasive performance and in situ molding. OBJECTIVE:To prepare a thermo-sensitive injectable alginate/α-tricalcium phosphate (α-TCP)/collagen I (Alg/TCP/Col) composite hydrogel and explore its characterization. METHODS:Ca-carrying interdigitation-fusion vesicles (Ca-IFVs) were prepared. The liposomes carrying the optimal concentration of calcium ions were selected for the following experiments by investigating their encapsulation efficiency and drug loading rate. Alg/TCP/Col precursor solution (Alg or Alg/TCP precursor solution) was mixed with Ca-IFVs at 37℃ in different proportions (5, 10, 15, 20) to prepare thermosensitive hydrogels. The structure, rheology behavior, volume swelling ratio, and mechanical properties of the composite hydrogel were observed. MC3T3-E1 cells were co-cultured with Alg/TCP/Col, Alg, and Alg/TCP hydrogels, respectively. Then, morphology of the cells was observed by confocal microscopy at 1, 3, 7 days after co-culture. RESULTS AND CONCLUSION:(1) The pore size of the freeze-dried hydrogel was 50-100 μm, and TCP particles uniformly adhered to the surface of the Alg/TCP hydrogel surface. The Alg/TCP/Col hydrogel was a dense aggregate with collagen fibers in contrast to the Alg/TCP hydrogel. (2) The Alg/TCP/Col hydrogel exhibited a suitable phase transition temperature (Tm) between 35-39℃. (3) The volume swelling ratio of the hydrogel was increased with the increase of Ca-IFVs size. When the α-TCP complex was added into the Alg/TCP hydrogel, the swelling ratio decreased slightly. Alg/TCP/Col hydrogel exhibited a higher swelling ratio than the Alg/TCP hydrogel. (4) When the mixture ratio of precursor solution to liposome was 10, the compressive modulus of Alg/TCP/Col hydrogel and Alg/TCP hydrogel was significantly higher than that of the Alg hydrogel (P<0.05). (5) When the mixture ratio of precursor solution to liposome was 10, round MC3T3-E1 cells were observed on the Alg hydrogel; the cells on the surface of the Alg/TCP hydrogel were scattered and tended to extend; the cells on the surface of the Alg/TCP/Col hydrogel had a stress-extended morphology, and grew into the hydrogel, and meanwhile, the cell number increased significantly. To conclude, the liposome-mediated Alg/TCP/Col has good mechanical properties and cytocompatibility.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the levels of DR4 and DR5, the death receptor of soluble tumor necrosis factor-related apoptosis inducing ligand (TRAIL) in the patients with congestive heart failure (CHF) and the effect of shengmai injection (SI) on them.</p><p><b>METHODS</b>Sixty-four CHF patients were randomized into two groups, the SI group treated by SI and the control group treated with conventional treatment. Another 30 healthy persons were enrolled as the healthy control group. The serum levels of sDR4 and sDR5 were determined by sandwich ELISA before and after treatment.</p><p><b>RESULTS</b>The serum levels of sDR4 and sDR5 were obviously higher in CHF patients than in the healthy control subjects (P < 0.01), showing a rising trend with the aggravation of the degree of cardiac function impairment. Levels of sDR4 and sDR5 were lowered in the two treated groups after treatment, with better effects gotten in the SI group.</p><p><b>CONCLUSION</b>Close relationship presents between cardiac function status and levels of DR4 and DR5 in patients with CHF. DR4 and DR5 might play an important role in the occurrence and progression of myocardial cell apoptosis in patients with CHF, and SI may acts vitally to slow down the progress of CHF and improve patients' heart function by decreasing the levels of sDR4 and sDR5.</p>