1,25-二羟维生素D3对Th1优势应答大鼠免疫功能的影响

Objective To study the immunomodulative effects of 1,25-Dihydroxyvitamin D3[1,25-(OH)2D3] on the predominant Th1 response rats. Methods Lewis rats had been led with 1,25-(OH)2D3 (1000ng per rat) for 14 days. The rats in control group were administered vehicle with the same volume as the drug to serve as the experimental group, and then LPS (10ng/kg) was administered intraperitoneally in both groups on the 15th day. 15 rats of each group were sacrificed 6h later and immunological index was measured. Mortality of the remaining ten rats in both group have been observed. Results There was no death in experimental group, while five control rats died at 24h (5/10, 50%), and all the other five control rats survived at 96h. IL-12 and IFN-γ were decreased significantly in the experiment group compared with control (3986±328pg/ml vs 4160±289pg/ml, P=0.028; 4840±802pg/ml vs 5264±524pg/ml, P=0.020), while IL-4 was increased (5.57±1.75pg/ml vs 3.72±1.62pg/ml, P=0.036). In white pulp of the spleen of experimental rat the number of lymphocytes decreased significantly as shown with HE-staining, and the PCNA positive cells were distributed focally or dispersively. In addition, by using flow cytometer, it was found that CD4(superscript +) CD25(superscript +) positive lymphocytes were increased significantly in the spleen of experimental rats (1.09%±0.29% vs 0.73%±0.00%, P＜0.001). Conclusion 1,25-(OH)2D3 could Protect rats from a challenge of a lethal dose of LPS. It also has a comprehensive modulation effect on the production of cytokines, proliferation of lymphocytes and differentiation of lymphocytes subpopulations in predominant Th1 response rats.