[Therapeutic effect of adipose tissue-derived stem cells on bleomycin-induced mice of scleroderma]

To investigate the effects and mechanisms of adipose-derived stem cells (ADSCs) on bleomycin-induced mice of scleroderma.

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.

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.

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.