Abstract:

Objective： To investigate the effects and mechanisms of adipose-derived stem cells (ADSCs) on bleomycin-induced mice of scleroderma. Methods: In the study, 24 C57BL/6J female mice were randomly divided into  control group, bleomycin（BLM）group, ADSCs (hypodermic injection) group  and  ADSCs (intravenous injection) group . BLM ［2 mg/(kg·d)］ was injected into the mice to establish the model of scleroderma. There were 6 mice in each group .The control group mice were injected with normal saline 2 mL/(kg·d) by subcutaneously. The rest of the three groups were injected with BLM. ADSCs groups were injected with ADSCs (2×105) subcutaneously and intravenously, respectively. T-helper 17 (Th17 ) and regulatory T cell (Treg cell) of spleen cells were detected by flow cytometry. The levels of cytokines in the lung tissue and in the serum were detected by real-time fluorescence quantification. Real-time polymerase chain reaction（PCR） and enzyme-linked immuno sorbent assay（ELISA）. The pathology change of skin and lung tissue was observed by hematoxylin eosin （HE）staining. Results: The proportion of Th17 and Treg increased in BLM group than in control group(15.30%±1.29% vs.4.32%±0.79%; 9.90%±1.95% vs.5.18%±1.35%, P<0.05), the expression of Th17 significantly decreased (5.02%±0.83%, 6.00%±0.82% vs.15.30%±1.29%, P<0.05) and the expression of Treg increased after the ADSCs therapy (14.32%±1.59%, 11.09%±4.31% vs. 9.90%±1.95%, P<0.05). The expression levels of IL-17，IL-6，tumor necrosis factor -α （TNF-α）mRNA in the lung tissue and IL-6 in the serum increased in BLM group than in control group ［3.54±0.30, 10.65±0.66, 5.37±0.52 vs. 1.00±0.00; (21.2±1.74) ng/L vs. (16.87±1.09) ng/L, P<0.05］. The expression of these cytokines significant decreased after the ADSCs therapy ［1.63±0.45,1.50±0.29 vs.3.54±0.30; 3.11±0.85, 2.98±0.76 vs.10.65±0.66;1.45±0.47, 1.59±0.41 vs. 5.37±0.52; (17.87±1.45) ng/L, (17.61±1.16) ng/L vs. (21.2±1.74) ng/L, P<0.05］. But there was no obvious difference between ADSCs (hypodermic injection) group and ADSCs (intravenous injection) group（P>0.05). The expression of TGF-β in the serum increased in BLM group than in control group［(33.95±2.49) ng/L vs. (28.8± 2.29) ng/L, P<0.05］, however, the expression of TGF-β mRNA had no significant differences than that of control group (1.17±0.11 vs.1.00±0.00, P>0.05). The expression of TGF-β mRNA and protein had no significant differences than that of BLM group ［1.25±0.11,1.26±0.12 vs.1.17±0.11; (31.84±2.04) ng/L, (31.25±2.36) ng/L vs. (33.95±2.49) ng/L, P>0.05］. HE staining showed that the inflammation of lung tissue was relieved and the dermal thickness and collagen deposition were decreased after the ADSCs therapy. Conclusion: ADSCs could effectively alleviate inflammation of the lungs and fibrosis of skin; the effects of antiinflammatory and antifibrosis were associated with immune regulating function.

Key words: Stem cells, mesenchymal, Scleroderma, Immune regulation, Cytokines