Benzene exposure has been associated with hematotoxicity and leukemogenicity. However, the impact of benzene exposure on complex microenvironment of Hematopoetic Stem Cells (HSCs) niche, comprising of HSCs and lineage-specific progenitors remains elusive. Thus, a study on benzene-targeting HSCs niche could uncover mechanism linking benzene to HSCs niche alteration. This study evaluates the lineage-specific responses following exposure to a benzene metabolite, namely hydroquinone (HQ) in targeting HSCs and myeloid-committed progenitors. Freshly isolated murine bone marrow cells (BMCs) were exposed to HQ at series of concentrations (0 – 50 μM) for 24 hours; followed by cell viability analysis using MTT assay. Chromosomal aberration (CA) status was determined using karyotyping analysis. Expression of surface antigen for HSCs (Sca-1) was confirmed by flow cytometer. Lineage-specific myelotoxicity was studied using the colony-forming unit (CFU) assay for the following myeloid progenitors: CFU granulocyte /erythrocyte /macrophage /megakaryocyte (CFU-GEMM), CFU-granulocyte/macrophage (CFU-GM), CFU-granulocyte (CFU-G), CFU-macrophage (CFU-M), CFU-erythroid (CFU-E) and Burst-forming unit erythroid (BFU-E). HQ reduced (p
Monosodium glutamate (MSG) is widely used in food preparation industry and has been consumed regularly. Previous studies had reported on effects of MSG when given at extremely high dosages, the results are not applicable to human equivalent intake. Therefore, the present study aimed to evaluate the effect of MSG on sperm quality and changes in reproductive organs of adult male rats when taken at average human daily intake (ADI). Twenty-four adult male rats were randomly assigned into three groups; NC (Normal control), MSG60 and MSG120 where MSG was given orally at 60 mg/kg and 120 mg/kg to each respective group. All treatments were conducted for 28 consecutive days. MSG at estimated ADI of 120 mg/kg body weight resulted in a significant drop in sperm quality (p
Hematopoietic stem/progenitor cells (HSPCs) are susceptible to benzene-induced genotoxicity. However, little is known about the mechanism of DNA damage response affecting lineage-committed progenitors for myeloid, erythroid, and lymphoid. Here, we investigated the genotoxicity of a benzene metabolite, 1,4-benzoquinone (1,4-BQ), in HSPCs using oxidative stress and lineage-directed approaches. Mouse bone marrow cells (BMCs) were exposed to 1,4-BQ (1.25-12 μM) for 24 h, followed by oxidative stress and genotoxicity assessments. Then, the genotoxicity of 1,4-BQ in lineage-committed progenitors was evaluated using colony forming cell assay following 7-14 days of culture. 1,4-BQ exposure causes significant decreases (p < 0.05) in glutathione level and superoxide dismutase activity, along with significant increases (p < 0.05) in levels of malondialdehyde and protein carbonyls. 1,4-BQ exposure induces DNA damage in BMCs by significantly (p < 0.05) increased percentages of DNA in tail at 7 and 12 μM and tail moment at 12 μM. We found crucial differences in genotoxic susceptibility based on percentages of DNA in tail between lineage-committed progenitors. Myeloid and pre-B lymphoid progenitors appeared to acquire significant DNA damage as compared with the control starting from a low concentration of 1,4-BQ exposure (2.5 µM). In contrast, the erythroid progenitor showed significant damage as compared with the control starting at 5 µM 1,4-BQ. Meanwhile, a significant (p < 0.05) increase in tail moment was only notable at 7 µM and 12 µM 1,4-BQ exposure for all progenitors. Benzene could mediate hematological disorders by promoting bone marrow oxidative stress and lineage-specific genotoxicity targeting HSPCs.
Previous reports on hematotoxicity and leukemogenicity related to benzene exposure highlighted its adverse effects on hematopoiesis. Despite the reported findings, studies concerning the mechanism of benzene affecting chromosomal integrity in lineage-committed hematopoietic stem/progenitor cells (HSPCs) remain unclear. Here, we studied the clastogenicity and aneugenicity of benzene in lineage-committed HSPCs via karyotyping. Isolated mouse bone marrow cells (MBMCs) were exposed to the benzene metabolite 1,4-benzoquinone (1,4-BQ) at 1.25, 2.5, 5, 7, and 12 μM for 24 h, followed by karyotyping. Then, the chromosomal aberration (CA) in 1,4-BQ-exposed hematopoietic progenitor cells (HPCs) comprising myeloid, Pre-B lymphoid, and erythroid lineages were evaluated following colony-forming cell (CFC) assay. Percentage of CA, predominantly via Robertsonian translocation (Rb), was increased significantly (p < 0.05) in MBMCs and all progenitors at all concentrations. As a comparison, Pre-B lymphoid progenitor demonstrated a significantly higher percentage of CA (p < 0.05) than erythroid progenitor at 1.25, 2.5, and 7 μM as well as a significantly higher percentage (p < 0.05) than myeloid progenitor at 7 μM of 1,4-BQ. In conclusion, 1,4-BQ induced CA, particularly via Rb in both MBMCs and HPCs, notably via a lineage-dependent response. The role of lineage specificity in governing the clastogenicity and aneugenicity of 1,4-BQ deserves further investigation.