Objective To evaluate the cytotoxicity of microdosis peracetic acid (PAA) so as to provide the evidence for making residual l imit of PAA steril ization. Methods Mouse fibroblasts (L929 cell l ine) cultured in vitro were observed to evaluate the influence of microdosis PAA including 1 × 10-6, 2 × 10-6, 3 × 10-6, 4 × 10-6, 5 × 10-6, and 10 × 10-6 (V/V). Theproliferation of cells was determined by MTT assay at 2, 4, and 7 days of culture. The growth curve and the relative growth rate (RGR) were obtained. The cytotoxicity of PAA at different concentrations was evaluated according to RGR. Results At 2, 4, and 7 days after culture, fibroblasts of 1 × 10-6 group grew with normal morphology analogous to control group, while the cell growth of other groups were poor. With the increase of PAA concentration, the absorbance (A) values decreased, which suggested that there was a significant negative correlation between cell prol iferation and PAA concentration. And the correlation coefficient was — 1.000 at 2 and 4 days, — 0.964 at 7 days. There was no significant difference in A value between 1 × 10-6 group and the control group (P gt; 0.05), while there were significant differences in A value between the control group and other concentration groups (P lt; 0.05). The growth curve of 1 × 10-6 group was similar to that of the control group, both had obvious phase of exponential growth. The growth curves of other groups had no obvious phase of exponential growth. The cytotoxicity of 1 × 10-6 group was classified as level 1, 2 × 10-6 group as level 2, 3 × 10-6 group as level 3, 4 × 10-6 group as level 3-4, 5 × 10-6 group and 10 × 10-6 group as level 4. Conclusion PAA of 1 × 10-6 had no obvious cytotoxicity. The residual l imit of PAA less than 1 × 10-6 was recommended.
Objective To investigate the feasibility of a new kind of porous β tricalcium phosphate (β-TCP) as a scaffold for the bone tissue engineering Methods The inverted phase contrast microscope was used to observe the growth of the marrow mesenchymal stem cells (MSCs) in the experimentalgroup and the control group at 10 days.In the experimental group, the MSCs were cultured with β-TCP(3 mm×3 mm×3 mm) in the 24-hole cultivation board, and in the control to control group, only MSCs were cultivated. The scanning electron microscope was used to observe growth of MSCs at 6 days. Cultivated with β-TCP at 3, 6, 9, 12 days, the MTT assay was used to judge the biocompatibility. The cytotoxicity was analyzed with the method that used the different density(100%， 50%， 10%， 1%，0%) leaching liquor gained from β-TCP to raise MSCs. MSCs were induced into the osteoblasts and were mixed with β-TCP, and the composite was used to repair a large radius bone defect in the rabbit. The specimens were made at 2,6,12 weeks. The histology imageology, and the radionuclide bone scan were used to analyze the bone formation. Results Some MSCs had a good adherence 4 hours after MSCs were inoculated and had a complete adherence at 12 hours. The cells were shaped like polyangle, spindle or converge monolayer after 8-10 days. The cells in the two groups had no difference. The cell adhesion was good, when observed by the inverted phase contrast microscope and the scanning electron microscope at 6 days. MTT showed that the absorbance (A)was not statistically different between the experimental group and the control group (P＞0.05); the different density leaching liquor had no cytotoxicity at the different time points. Histology, X-ray, and CT tomograph showed that itcould repair the large radius bone defect in the rabbit and its in vivo degradationrate was the same as the bone formation rate. Conclusion The new porous β-TCP has a unique three dimensional (3D) stereochemical structure and superordinary physicochemical property, and so it is a good scaffold for the bone tissue engineering.
Objective To investigate the cell compatibility of the porcine acellular lumens matrix substituting bile duct and evaluate the method to guide the clinical application of the porcine lumens scaffold. Methods Porcine bile duct and ureter were treated using detergent sodium dodecylsulphate (SDS) and 1% Triton X-100 to prepare the acellular lumens matrix. The toxic effects of different concentrations of acellular lumens matrix extract were tested by MTT to assess the proliferation of human scarfskin fibroblasts (HSF). The cytotoxicity of the target biomaterial was graded according to the national standards. The growth manner of the human intrahepatic bile duct endothelial cells (HIBDCs) seeded on the acellular lumens matrix was studied after 20 d under scanning electron microscopy.Results Acellular lumens matrix was completely devoid of cellular and nuclear material while maintaining the integrity of extracellular collagenous matrix. The cytotoxicity score of the matrix was in grade 0－1, which meant the biomaterial had no cytotoxicity. The microscopy showed the seeded HIBDCs had the potentials of spread and proliferation on the matrix, but there were few cells infiltrating into the acellular lumens matrix. Conclusions Porcine acellular lumens matrix is a natural non-toxic xenogenic lumens substitute with good cell affinity, but the time of adherence is long, so further endeavors are needed to improve the progress of adherence.
ObjectiveTo investigate the effect of expressions of nucleoside transporters subtype (hENT1 and hENT2) on 5-fluorouracil(5-FU) cytotoxicity in breast cancer cell lines(MDA-MB-231, MDA-MB-468, SK-BR-3, MCF-7). MethodsFour breast cancer cell lines were chosen to detect the mRNA expressions of hENT1 and hENT2 by RT-PCR. Cells were incubated in the medium with a serial concentrations of 5-FU from 1.28×104 ng/L to 2.00×108 ng/L for 48 h. Then the cell proliferation in each cell line was measured by MTT assay and the IC50 was evaluated. Results①The mRNA expressions of hENT1 and hENT2 in the MDA-MB-231, MDA-MB-468, or SK-BR-3 cells were significantly higher than thoes in the MCF-7 cells(P < 0.05). The mRNA expression of hENT2 was detected in the MDA-MB-231, MDA-MB-468, or SK-BR-3 cells, not detected in the MCF-7 cells. 2MTT showed that IC50 of 5-FU in the MDAMB-231, MDA-MB-468, or SK-BR-3 cells was significantly lower than that in the MCF-7 cells(P < 0.05). There was no statistical difference of IC50 among the three lines(MDA-MB-231, MDA-MB-468, and SK-BR-3)(P > 0.05).③The three lines(MDA-MB-231, MDA-MB-468, and SK-BR-3) with lower IC50 of 5-FU highly expressed hENTs, and MCF-7 cell with the higher IC50 of 5-FU expressed less hENTs. ConclusionsThe expressions of hENTs in breast cancer cell lines can significantly influence 5-FU cytotoxic effect. It is implicated that the hENTs expressions might be the clue to the choice of nucleoside anticancer drugs in clinic.