Objective To investigate the effect of human placental-derived mesenchymal stem cells (PMSCs) on immunological rejection in mouse allogeneic skin transplantation. Methods The placenta fetal tissues from voluntary donors were used to isolate and culture the PMSCs, and the 3rd passage PMSCs were used in the experiment. Thirty Vr ∶ CD1 (ICR) mice at age of 1-2 days were used as skin donors for allogeneic skin transplantation. Thirty C57BL/6 mice at age of 6-8 weeks as recipients were made back skin defect of 12 mm in diameter and were randomly divided into 3 groups (n=10): group A, autograft; group B, allogeneic graft + PBS tail vein injection; and group C, allogeneic graft + human PMSCs (1 × 105 cells/mouse) tail vein injection. The flap survival was observed. At 7 days after skin transplantation, blood leukocyte counting, abdominal fluid macrophage activation, and the expression levels of interleukin 4 (IL-4), interleukin 17 (IL-17), and interferon γ (INF-γ) in blood and spleen were detected by ELISA and RT-PCR, respectively. Results The flap survival time was significantly longer in group A [(58.33 ± 4.04) days] than in groups B and C [(3.80 ± 0.92) days and (6.80 ± 0.82) days] (P lt; 0.05), and in group C than in group B (P lt; 0.05). At 7 days after transplantation, the blood leukocyte number was (6.32 ± 0.45) × 109/L in group A, (7.45 ± 0.52) × 109/L in group B, and (6.35 ± 0.39)× 109/ L in group C, and it was significantly more in group B than in groups A and C (P lt; 0.05). The macrophage activation rate of the abdominal fluid was 6.87% ± 2.40% in group A, 7.84% ± 0.44% in group B, and 15.98% ± 2.87% in group C; group C was significantly higher than groups A and B (P lt; 0.01). ELISA results showed that there was no significant difference in the concentrations of IL-4 among 3 groups (P gt; 0.05). Compared with group B, the concentrations of IL-17 and IFN-γ were significantly reduced in group C (P lt; 0.05), while the concentration of IFN-γ was significantly increased in group B when compared with group A (P lt; 0.05). RT-PCR results showed that there were significant differences in the expressions of IL-4, IL-17, and IFN-γ mRNA between groups B, C and group A (P lt; 0.05); the expressions of IL-4 and IFN-γ mRNA were significantly lower in group C than in group B (P lt; 0.05). Conclusion Human PMSCs transplantation can suppress the acute immunological rejection in allogeneic skin transplantation. The possible mechanism may be partially related to the inhibitory effect on the secretion of IL-17 and IFN-γ.
Objective To investigate the effect of hepatocyte-l ike cells induced by CD34+ cells in vitro on the repair of the injured hepatic tissues of mice in vivo. Methods Mononuclear cells were isolated from umbil ical blood by density gradient centrifugation and enriched CD34+ cells were obtained. The cells were (1 × 105 cells/mL) cultured in serumfreemedium containing stem cell factor (SCF), hepatocyte growth factor (HGF), EGF, oncostatin M (OSM), bFGF (the concentration were 50, 20, 20, 10, 10 ng/mL respectively) in vitro for 10 days. Forty-eight 6-week-old female ICR mice werechosen to prepare l iver injury model by injecting carbon tetrachloride and 2-acetylamionoflu-orene. The mice were randomly divided into two groups (n=24 per group): the experimental group, the cultured cells were injected into the mice through the tail vein; the control group, the equivalent serum-free medium was injected. Six mice from each group were killed at 7, 14, 21, and 28 days after operation to receive HE staining, PCR gel electrophoresis, immunohistochemistry staining, and hepatic function detection. Results HE staining: the morphology of injured hepatic tissues in the control group recovered to normal 28 days after operation, while in the experimental group, it recovered to normal 14 days after operation. PCR gel electrophoresis and immunohistochemistry staining: the cells expressing human serum albumin were detected in the hepatic tissue of the experimental group at each time point after operation; while in the control group, no such cells were detected within 28 days after operation. Hepatic function detection: the activity of alanine aminitransperase in the control group recovered to normal 14 days after operation; the mean activity of aspartate aminotransferase of two groups failed to recover within 28 days. Conclusion The hepatocyte-l ike cells induced by CD34+ cells in vitro can promote the morphological and functional recovery of the injured hepatic tissue in mice. Moreover, it can be transformed into human-derived hepatic cells in l iver-injured mice.