Abstract: AIM: To explore the effect of lienal polypeptide injection (LPI) on platelet production in ITP model mice with primary immune thrombocytopenia.  METHODS: SPF Kunming mice were divided into groups by random number table method, and the ITP model of mice was induced by intraperitoneally injected of rabbit anti-mouse platelet serum APS every other day. At the set time, blood was collected through caudal vein to detect the changes in the number of platelets, red blood cells and white blood cells in each group. Meanwhile, the thymus and spleen indexes were calculated. Megakaryocytes were classified and counted by means of bone marrow smear. Finally, the expression levels of TPO, SCF, IL-3, IL-6, IL-11, β-TG, TGF-β1 and PF-4 in serum were detected by ELISA. RESULTS: LPI significantly increased platelets count in ITP model mice, but had no effect on red blood cells and white blood cells. Thymus and spleen index decreased significantly. The number of megakaryoblasts and thrombocytopenia megakaryocytes in the bone marrow of mice increased, but the number of promegakaryocytes, granular megakaryocytes and naked megakaryocyte did not change significantly. Serum sytokines SCF, IL-3 and IL-6 were significantly increased, while PF-4 was decreased significantly. CONCLUSION: LPI may increase the platelet count in ITP mice by up regulating the levels of IL-3, IL-6, SCF and down regulating the level of PF-4, which has guiding significance for clinical promotion application of LPI.

Key words: lienal polypeptide injection, primary immune thrombocytopenia, platelet, red blood, megakaryocyte