Single-Cell Transcriptomics Reveals Early Effects of Ionizing Radiation on Bone Marrow Mononuclear Cells in Mice.

Ionizing radiation exposure can cause damage to diverse tissues and organs, with the hematopoietic system being the most sensitive. However, limited information is available regarding the radiosensitivity of various hematopoietic cell populations in the bone marrow due to the high heterogeneity of the hematopoietic system. In this study, we observed that granulocyte-macrophage progenitors, hematopoietic stem/progenitor cells, and B cells within the bone marrow showed the highest sensitivity, exhibiting a rapid decrease in cell numbers following irradiation. Nonetheless, neutrophils, natural killer (NK) cells, T cells, and dendritic cells demonstrated a certain degree of radioresistance, with neutrophils exhibiting the most pronounced resistance. By employing single-cell transcriptome sequencing, we investigated the early responsive genes in various cell types following irradiation, revealing that distinct gene expression profiles emerged between radiosensitive and radioresistant cells. In B cells, radiation exposure led to a specific upregulation of genes associated with mitochondrial respiratory chain complexes, suggesting a connection between these complexes and cell radiosensitivity. In neutrophils, radiation exposure resulted in fewer gene alterations, indicating their potential for distinct mechanisms in radiation resistance. Collectively, this study provides insights into the molecular mechanism for the heterogeneity of radiosensitivity among the various bone marrow hematopoietic cell populations.

[Histomorphological feature of silicotic nodules under Warthin-Starry silver staining and its possible prompt value in the histopathologic examination].

OBJECTIVE: To investigate histomorphological feature of silicotic nodules under Warthin-Starry (WS) silver staining and its value in the histopathological examination. METHODS: Six cases with silicosis obtained by autopsy and 21 cases with sarcoidosis were collected (among which 3 cases were obtained by autopsy and 18 cases were obtained by biopsy). The serial sections of those paraffin embedded samples were applied respectively for (1) hematoxylin and eosin (HE) staining, (2) WS staining, (3) streptomyces avidin-peroxidase (SP) immunohistochemical staining for mouse anti-human CD68 monoclonal antibody, (4) observing under transmission electron microscope (TEM), (5) X-ray spectrum chemical element analysis(X-RSA). The emphasis of observation and analysis were the dust particles in silicotic nodules and granulomas cells (dust cells, epithelioid cells and multinucleated giant cells in the granulomas). The dust particles deposit in the granulomas were graded under the HE and WS staining. RESULTS: Under the HE staining the dust particles deposit degrees were (+++) in cellular silicotic nodules, (+) in the fibrous ones, and (-) in the sarcoid nodules; under the WS staining and the dust particles deposit degrees were (+++) in both silicotic nodules whose dust particles were characteristically black, and (+/++) in sarcoid nodules. The dust particles deposit degrees in silicotic nodules were markedly higher than those in sarcoidosis (P < 0.01). The results of immunohistochemical staining indicated that the expression of CD68 in both cells of silicotic nodules and sarcoid nodules were positive. The positive degrees decreased successively with the content of the dust particles. The dust particles of silicotic nodules could be more readily observed than those of sarcoidosis in size and electronic density under TEM. The results of X-RSA indicated that the main chemical element in both dust particles was silicon. CONCLUSION: WS staining is better than HE staining in showing the dust particles of silicotic nodules, which appear characteristically black, especially in the fibrous ones. Together the TEM observation and X-RSA, the silicotic nodules may be prompted.