Effect of rTMP-GH recombinant fusion protein on thrombocytopoiesis in irradiation injured mice

Abstract

Objective To investigate the in vivo effects of rTMP-GH recombinant fusion protein on thrombocytopoiesis in mice with thrombopenia inflicted by irradiation. Methods BALB/C mice weighting around 20 g were irradiated with 5 Gy of ~(60)Co γ-ray irradiation to generate thrombopenia. The irradiation injured mice were injected with rTMP-GH or rhGH subcutaneously at the dose of 200 (μg·kg~(-1) ·d~(-1) for 7 days. From the 6 th day, the platelets in blood samples from vena caudalis were counted routinely, and the pathological changes of bone marrow were determined by morphological observation. Results From the 10 th day, the levels of blood platelet in rTMP-GH treated mice were much higher than those of rhGH treatment group and normal saline (NS) control group, especially at the nadir (P < 0.01). On the 22 nd day, the platelet count has recovered up to 80% of normal level in rTMP-GH treatment group, while it has just recovered up to 30% in NS control group. Morphological observation showed that there was obvious reconstruction of bone marrow in mice treated with rTMP-GH, compared with NS group.The number of megarkaryoblasts and megakaryocytes in bone marrow of rTMP-GH treated mice (3.07 ± 0.32) was much higher than those of rhGH treatment group (2.20 ±0.22, P < 0.05) and NS control group (0.87 ±0.19, P <0.01). Conclusions rTMP-GH has potent effects on the recovery of blood platelet by promoting megarkaryocytopoiesis in irradiation injuried mice. Key words: Thrombopoietin mimetic peptide; Growth hormone; Irradiation injury; Thrombocytopoiesis