Mechanism of recombinant human bone morphogenetic protein-2 in repairing hematopoietic injury in mice exposed to γ-rays

Abstract

Objective To investigate the mechanism of recombinant human bone morphogenetic protein-2(rhBMP-2)in repairing hematopoietic injury in mice irradiated with γ-ray.To prepare SRY gene probe and study the effect of rhBMP-2 in repairing hematopoietic injury in mice by in situ hybridization.Methods Twenty-two BALB/c female mice were randomly divided into the irradiated group and BMP treated group,respectively.Bone marrow cells of normal male mice were transplanted into 22 female mice post-irradiation to 8.5 Gy of 60 Co γ rays.The left femurs of the survived female mice were re-irradiated with 9 Gy 14 days later.Mice in BMP treated group were given rhBMP-2 20 mg/kg while those in control group were treated with 0.9% saline by intraperitoneal injection every day for 6 days.These mice were killed 14 days later and paraffin sections of femurs were made.The SRY gene was detected with in situ hybridization.Results There were more positive blots in the left femurs of the mice in irradiated group than those in BMP treated group(T=155.0,P＜0.05).The number of positive blots between the left femurs of the mice in irradiated group and the right femurs of the mice in two groups was not significantly different(T=92.0,78.5,P＞0.05).The number of positive blots in the left femurs of the mice in BMPtreated group was significantly less than those in the right femurs of the mice in two groups(T=155.0,55.0,P＜0.05).Conclusions No donor cell of male mice was detected in the left femurs of BMP treated group,suggesting that rhBMP-2 promoted the restoration of residuary bone marrow cells.Thus,rhBMP-2 promotes the proliferation or differentiation of residuary mesenchymal stem cells,improves hematopoietic microenvironment and accelerates the hematopoietic restoration. Key words: Bone morphogenetic protein; Hematopoiesis; Radiation injury; SRY gene; DNA probe