ABSTRACT
Objective To study the immunosuppressive mechanism of alkaloid sinomenine (SIN) by observing the effects of SIN on the proliferation and intracellular protein expression levels of nuclear factor of activated T cells (NF-AT) and interferon-gamma (IFN-γ) in CD4+ T lymphocytes of human periphery blood. Methods CD4+ T lymphocytes were isolated from PBMC suspensions with immunomagnetic beads and divided into five groups to culture. (1) Negative control group: no medicine was added to cell culture medium; (2) Positive control group: CsA solution (final concentration: 50ng/ml) was added to cell culture media; (3) Low-concentration SIN group (L-SIN): low-concentration SIN solution (final concentration: 10 μmol/L) was added to cell culture media; (4) Middle-concentration SIN group (M-SIN): middle-concentration SIN solution (final concentration: 200 μmol/L) was added to cell culture media; (5) High-concentration SIN group (H-SIN): high-concentration SIN solution (final concentration: 1000 tmol/L) was added to cell culture media. The proliferations of CD4+ T lymphocytes were observed. Western blotting was performed to detect the protein expression levels of NF-AT. FCM was used to determine the levels of IFN-γ. Results Compared with negative control group, the cell proliferation was significantly inhibited in H- and M-SIN groups (P＜0. 01 ). SIN concentration-dependently inhibited the protein expression levels of NF-AT and IFN-γ in CD4+ T lymphocytes of human periphery blood (P＜0.01). The protein expression levels of NF-AT and IFN-γ were lowest in positive control group. There was a close negative correlation between intracellular levels of NF-AT and cell proliferation inhibition ratio in CD4+ T lymphocytes of human periphery blood (rs = - 0. 969, P = 0. 000). Conclusion SIN can inhibit the protein expression of NF-AT and IFN-γ in CD4+ T lymphocytes of human periphery blood probably by decreasing protein levels of NF-AT to inhibit the activity and proliferation of CD4+ T lymphocytes.