Biophysical characteristics of genipin-crosslinked amniotic membrane bio-scaffold / 中华实验眼科杂志

Objective To investigate the characteristics and feasibility of genipin-crosslinked amniotic membrane(AM) as bio-scaffold.Methods Human umbilical cord mesenchymal stem cells (hUCMSCs) were isolated from fresh umbilical cord and cultured by adherent method.The expressions of PE-CD34,PE-CD45,PE-CD90,FITC-105 and FITC-Oct-4,the markers of hUCMSCs,were detected by flow cytometry.Alizarin red and oil red O staining were performed to identify the cells after adipogenesis and osteogenesis induction on the third-generation cells.Human AMs were treated at 37 ℃ and 45 ℃ by 0.5％ and 1％ genipin solution for 24,36 and 48 hours respectively,and the mechanical properties of AM in each group were measured and compared.The hUCMSCs were divided into only hUCMSCs culture group,fresh AM group,crosslinked AM group,gelatin group and crosslinked AM+gelatin group,and the cells were cultured in the corresponding medium.The content of hydroxyproline among the groups was detected with hydroxyproline kit,and proliferation of the cells (absorbance) was assayed by MTT method to evaluate the biological compatibility of crosslinked AM.Results The maximum tensile displacement of the crosslinked-AM by 0.5％ and 1％ genipin was (8.31±0.43)mm and (4.49±0.37)mm respectively,and those after crosslinked with 0.5％ genipin under the 37 ℃ and 45 ℃ for 24 hours was (9.89±1.09)mm and (5.39±0.59)mm,respectively,showing a significant difference between them (t =6.389,P＜0.05).The maximum tensile displacement of the crosslinked-AM was gradually decreased as the lapse of crosslinking time,and an insignificant difference was found among 24,36 and 48 hours after 0.5％ genipin treatment under the 37 ℃ (P＞0.05).The loading force of the crosslinked-AM was significantly higher in the 1％ genipin treated group than that in the 0.5％ genipin treated group (P＜0.05),and the loading force of the AM was significantly increased in 45 ℃,0.5％ genipin,24 hours crosslinked group compared with the 37 ℃,0.5％ genipin,24 hours crosslinked group (t =5.528,P＜0.05).The content of hydroxyproline in the AM was (1.28±0.36),(2.03 ±0.49) and (2.11 ±0.10) mg/g in the 1％ genipin crosslinked AM group,0.5％ genipin crosslinked AM group and fresh AM group,respectively,and the content of hydroxyproline in the AM in the 1％ genipin group was significantly lower than that in the 0.5％ genipin group in the fresh AM group (both at P＜0.05).The proliferative values of the hUCMSCs were significantly lower in the only hUCMSCs culture group,fresh AM group and gelatin group were significantly reduced in comparison with the crosslinked AM group and crosslinked AM+gelatin group (all at P＜0.05).There was no significant difference in the proliferative values of the hUCMSCs between crosslinked AM group and crosslinked AM+gelatin group (P＞0.05).Conclusions Different crosslinked temprature,crosslinking period and concentration of genipin impact the mechanical properties of AM.Crosslinked AM with genipin is feasible as a carrier scaffold of artificial cornea because of less tissue toxicity and better plasticity.

Fabrication and evaluation of a new decellularized tissue engineered blood vessel scaffold / 生物医学工程学杂志

The aim of this study was to fabricate an ideal nature-based tissue engineered blood vessel (TEBV) scaffold. It should have several special characteristics such as little immunogenicity and good biocompatibility, and it should be similar in mechanical property to fresh tissue. New-got canine aortas were dipped in ion-free water for 12 h under 4 degrees C to make the cells disrupted, then fixed in a kind of polyepoxy compounds solution (EX-810) for 72 h, and finally treated with sonication to remove the cell debris. Histological slices of the TEBV scaffold were stained with H&E. The results showed that our method could effectively remove the cells in fresh tissues because there was no visible nuclear stain. A series of biomechanical analyses revealed that these TEBV scaffold had nearly the same mechanical properties as fresh tissues. Also, these TEBV scaffolds showed good cell-compatibility, and their surfaces were suitable for endothelial cells and smooth muscle cells to grow on.

A sharp rise in portal vein pressure, not arterial constriction, initiates bile salt-induced pancreatic microcirculatory disturbance / 生物医学工程学杂志

It was reported that pancreatic arteries constricted during the early phase of bile salt-induced acute pancreatitis (AP), leading to pancreatic microcirculatory disturbance. We conducted this experiment to verify whether the above-mentioned finding was true. AP was induced with intraductal injection of taurodeoxyholate. Small pancreatic artery pressure in dogs was recorded. Functional capillaries were counted and calibrated by multiplying wet weight of pancreas. Pancreatic perfusion was measured with Laser Doppler flowmeter. Pancreatic arterioles of rats dilated during the initial 20 min of AP, and pancreatic arterial pressure declined during the early phase of AP in dogs (from 104.5 +/- 4.8 mmHg to 54.6 +/- 5.6 mmHg). The hematocrit of blood from inferior vena cava was significantly lower than that of portal vein at 5 min after pancreatitis induction. The "true" pancreatic functional capillary density increased. The early pancreatic microcirculatory disturbance coincided with a marked increase of portal vein pressure (PVP) as high as 9.18 +/- 0.78 mmHg. Reduction of PVP to baseline level was followed by a marked increase of pancreatic perfusion (by 1.4-fold). Arterial dilatation, but not constriction, occurred during the early phase of bile salt-induced AP. The pancreatic microcirculatory disturbance was due to a marked rise in PVP that greatly reduced the pressure difference in the pancreatic blood vessels and increased plasma extravasation which led. to local hemoconcentration.

Effects of Fluid Shear Stress on IL-8 mRNA Expression in EA.Hy926 Cells / 航天医学与医学工程

Objective To investigate the effects of fluid shear stress on interleukin-8(IL-8)mRNA expression in human endothelial cell line-EA.Hy926 cells.Methods Weibel-Palade body and factor Ⅷ related antigen were detected to identify cultured EA.Hy926 cells.Quantitative reversal transcription-polymerase chain reaction was also used to assay IL-8 mRNA expression.Results It was found that the growth feature of EA.Hy926 cells in vitro culture was similar with that of human umbilical vein endothelial cells(HUVECs).Meanwhile,it also had the typical features of endothelial cells,i.e.Weibel-Palade body in plasma and express factor Ⅷ related antigen.IL-8 mRNA expression of endothelial cells exposed to low shear stress(0.420 Pa)increased at 1 h and reached its peak value at 2 h,then gradually decreased at 3 h and kept the descending trend throughout the remained time course of the study,as compared with that in cells not treated with shear stress.Also after exposed to shear stress of different levels(0.182,0.420,1.000,1.640 Pa)for 2 h,in which IL-8 mRNA expression of EA.Hy926 cells decreased with the increase of the intensity of the shear stress.Conclusion The results suggest that fluid stress can induce the expression of IL-8 mRNA in EA.Hy926 cells.EA.Hy926 cells might be used as a cell source in the field of biorheological research of endothelial cells.