Effects of combined hypoxia and irradiation on mouse bone marrow hematopoietic cells
10.16016/j.2097-0927.202411032
- VernacularTitle:低氧联合辐照对小鼠骨髓造血细胞的影响作用研究
- Author:
Xinhai YANG
1
;
Fang CHEN
;
Yong QUAN
;
Mengjia HU
;
Yukai LU
;
Naicheng CHEN
;
Yang XU
;
Song WANG
;
Junping WANG
Author Information
1. 陆军军医大学(第三军医大学)军事预防医学系防原医学教研室
- Keywords:
hypoxic preconditioning;
hematopoietic stem/progenitor cells;
acute radiation injury;
hematopoietic function;
single-cell transcriptome technology
- From:
Journal of Army Medical University
2025;47(7):681-690
- CountryChina
- Language:Chinese
-
Abstract:
Objective To determine the effects of hypoxia pre-treatment combined with radiation damage on the hematopoietic cells in the bone marrow of mice.Methods A total of 165 male C57BL/6 mice(10～12 weeks old,weighing 20～25 g)were randomly divided into 7 groups:normal control(Control,n=33),6 Gy irradiation(6-Gy,n=43),7 d hypoxia-6 Gy irradiation(Hy-7 d+6 Gy,n=43),7 Gy irradiation(7 Gy,n=12),7 d hypoxia-7 Gy irradiation(Hy-7 d+7 Gy,n=12),7 Gy continuous hypoxia treatment(Hy-7 d+7 Gy+Hy,n=12),and 6 Gy continuous hypoxia treatment(Hy-7 d+6 Gy+Hy,n=10).The mice of the hypoxia treatment groups were given 7-day hypoxic pretreatment(12%oxygen)in a normobaric hypoxic chamber,while those of the other groups were housed in normoxic condition.After pretreatment,the mice of the irradiation groups were exposed to a single 6 or 7 Gy of whole-body 60Co γ-irradiation in normoxia.The mice of the hypoxia and irradiation groups were kept in hypoxic condition in 24 h post-irradiation followed by being resumed to normoxia,while those of the continuous hypoxia treatment groups were remained in hypoxia.After bone marrow cell suspensions were prepared from the Control,6 Gy,and Hy-7 d+6 Gy groups,bone marrow nucleated cells(BMNCs)were counted via automated cell counter.HE staining was employed to observe pathologic changes in medullary cavity,and flow cytometry was used to assess Lin-Sca1?c-Kit?(LSK)hematopoietic stem/progenitor cells,myeloid progenitors(MPs),and mature T/B/myeloid cells.The mice of the 7 Gy,Hy-7 d+7 Gy,and Hy-7 d+7 Gy+Hy groups were monitored for 30-day survival after hypoxic pretreatment.The dynamic changes in the counts of red blood cells(RBC),white blood cells(WBC)and platelets(PLT),and hemoglobin(HGB)level were observed in the 6 Gy,Hy-7 d+6 Gy,and Hy-7 d+6 Gy+Hy groups with aid of a fully automatic blood analyzer.Single-cell RNA sequencing was performed on bone marrow cell suspension derived from the mice euthanized in 17 d after irradiation from the Control,6 Gy,and Hy-7 d+6 Gy groups.Results ①Compared to the Control group,the 6 Gy group showed significantly reduced BMNCs(P<0.01),dilated bone marrow sinusoids,and erythrocyte extravasation.The Hy-7 d+6 Gy group exhibited higher cellular density and attenuated BMNC loss than the 6 Gy group(P<0.01).②Flow cytometry revealed less LSK,MP,and mature T/B/myeloid cells in the 6 Gy group than the Control group(P<0.05),and the reduced counts of LSK and MP were mitigated in the Hy-7 d+6 Gy group(P<0.01).③The Hy-7 d+7 Gy group demonstrated improved 30-day survival than the 7 Gy group(P<0.01),while continuous hypoxia(Hy-7 d+7 Gy+Hy)failed to enhance the survival.No statistical difference was seen in the survival rate between the 2 groups(P=0.12),though the Hy-7 d+7 Gy group showing higher survival rate.④Routine blood test revealed that the Hy-7 d+6 Gy group showed faster WBC recovery(vs the 6 Gy and Hy-7 d+6 Gy+Hy groups,P<0.05),higher pre-irradiation RBC/HGB levels,and accelerated PLT restoration(P<0.05).⑤Single-cell RNA sequencing indicated that hypoxia pretreatment suppressed the numbers of long-term hematopoietic stem cells/short-term hematopoietic stem cells(LT-HSC/ST-HSC)depletion in the Hy-7 d+6 Gy group when compared with the 6 Gy group,which was consistent with the results of flow cytometry.Pseudotime trajectory aligned the Hy-7 d+6 Gy group,as the Control group,showed enriched undifferentiated LSKs.Differential gene analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis revealed that oxidative phosphorylation pathway was strongly activated in the 6 Gy group,while the Hy-7 d+6 Gy group had enriched in chromatin remodeling and mRNA surveillance pathways.Conclusion Hypoxic preconditioning alleviates radiation-induced bone marrow injury,and post-irradiation normoxia restoration promotes hematopoietic recovery in acute radiation-exposed mice.
