Evaluation of the splenic injury following exposure of mice to bisphenol S: A mass spectrometry-based lipidomics and imaging analysis.

BACKGROUND: The widespread use of bisphenol A (BPA) substitutes has aroused great attention towards their toxicological evaluation in vivo and in vitro. Considering the intimate correlation between BPA and metabolic diseases, we explored whether bisphenol S (BPS), a major substitute to BPA, could cause the splenic toxicity by disturbing the lipid metabolism in mouse model. METHODS: We investigated the splenic injury by combing the mass spectrometry (MS)-based lipidomics and imaging analysis, as well as molecular biological methods. Mice were divided into three groups (control-olive oil, 10 and 100 µg-BPS/kg body weight/day group) and treated by BPS in 56 days. RESULTS: Two of BPS-treated concentrations induced the splenic morphological alterations and inflammation, including the decreased numbers and cellularity in the periarteriolar lymphoid sheath (T cell zone) and paucicellular primary lymphoid follicles (B cell zone) in splenic white pulp. Lipidome profiling of spleen after BPS treatment was also changed with up-regulated sphingosine [So], neutral glycosphingolipids [CerG], cholesteryl ester [ChE], diacylglycerols [DAG], lysophosphatidylcholine [LPC], lysophosphatidylethanolamine [LPE], phosphatidylglycerols [PG], phosphatidylinositols [PI] and phosphatidylserine [PS] as well as down-regulated ceramide [Cer], phosphatidylethanolamines [PE] and sphingomyelin [SM] compared to the control group. More importantly, significant different lipids in abundance and spatial distribution also implicated that white pulp were more sensitive to BPS treatment than other splenic sub-structures. Signaling lipids such as So (d18:0), Cer (d18:1/24:0), Cer (d18:1/22:0), SM (d18:1/22:1) and SM (d18:1/24:2) associated with inflammation were remarkable changed and co-localized in the splenic white pulp. CONCLUSIONS: Our finding indicated that BPS exposure promoted the splenomegaly, pro-inflammatory activation and morphological alterations, as well as induced the lipidome perturbation in the immune cells of white pulp, which might be expected to contribute a new perspective of bisphenol-induced organ injury.

Heterogeneity of stromal cells in the human splenic white pulp. Fibroblastic reticulum cells, follicular dendritic cells and a third superficial stromal cell type.

At least three phenotypically and morphologically distinguishable types of branched stromal cells are revealed in the human splenic white pulp by subtractive immunohistological double-staining. CD271 is expressed in fibroblastic reticulum cells of T-cell zones and in follicular dendritic cells of follicles. In addition, there is a third CD2711- and CD271+/) stromal cell population surrounding T-cell zones and follicles. At the surface of follicles the third population consists of individually variable partially overlapping shells of stromal cells exhibiting CD90 (Thy-1), MAdCAM-1, CD105 (endoglin), CD141 (thrombomodulin) and smooth muscle α-actin (SMA) with expression of CD90 characterizing the broadest shell and SMA the smallest. In addition, CXCL12, CXCL13 and CCL21 are also present in third-population stromal cells and/or along fibres. Not only CD27+ and switched B lymphocytes, but also scattered IgD++ B lymphocytes and variable numbers of CD4+ T lymphocytes often occur close to the third stromal cell population or one of its subpopulations at the surface of the follicles. In contrast to human lymph nodes, neither podoplanin nor RANKL (CD254) were detected in adult human splenic white pulp stromal cells. The superficial stromal cells of the human splenic white pulp belong to a widespread cell type, which is also found at the surface of red pulp arterioles surrounded by a mixed T-cell/B-cell population. Superficial white pulp stromal cells differ from fibroblastic reticulum cells and follicular dendritic cells not only in humans, but apparently also in mice and perhaps in rats. However, the phenotype of white pulp stromal cells is species-specific and more heterogeneous than described so far.

Effects of Antitumor Agents on Ultrastructure of the Splenic White Pulp of the Mouse Implanted with Ehrlich Carcinoma Cells / 대한해부학회지

This experiment was performed to study the morphological responses of the splenic white pulp, the lymphatic tissue of the spleen, of Ehrlich carcinoma cell-implanted mice to three different anticancer drugs (5-fluorouracil, mitomycin C and AG60). Healthy adult ICR mice weighing 20 g each were divided into normal and experimental groups. In the experimental groups, each of mice was inoculated with 1X10(7) Ehrlich carcinoma cells subcutaneously in the inguinal area. From next day, 0.2 ml of saline solution, 5-fluorouracil (30 mg/kg), mitomycin C (400 microgram/kg) or AG60 (30 mg/kg, Taerim Pharm. Co., Seoul, Korea) were injected subcutaneously every other day, and animals were sacrificed at 14th day following the f irst injection. Pieces of the tissues were taken from the spleen, and prefixed with phosphate buffered 2.5% paraformaldehyde-1.5% glutaraldehyde solution (pH 7.3) followed by post-fixation with phosphate buffered 1% osmium tetroxide solution (pH 7.3). Fixed tissue blocks were dehydrated, and embedded in araldite mixture. Ultrathin sections stained with uranyl acetate and lead citrate were observed with a JEM 100CX-II electron microscope. In the experimental control group (carcinoma cell-inoculated mouse), splenic white pulp did not show pronounced morphological alterations, but myelin figures were frequently observed in the cytoplasm of some lymphocytes and reticular cells than those of normal control mice. In the AG60 treated group, splenic white pulp did not show specific morphological defect, but nuclear bodies and severe invaginations of the nuclear envelope of the lymphocytes and reticular cells were observed occasionally. In the mitomycin C treated group, myelin figures, severe invaginations of the nuclear envelope, nuclear protrusions, nuclear bodies and interchromatin granules were frequently observed in the lymphocytes and reticular cells of the white pulp. In the 5-f luorouracil treated group, myelin f igures, severe invaginations of the nuclear envelope, nuclear protrusions, nuclear bodies and interchromatin granules were observed more frequently in the lymphocytes and reticular cells of the white pulp, as compared with those of mitomycin C treated mice. From the above results, 5-f luorouracil or mitomycin C may suppress the splenic immune function of cancerinoculated mice, since they suppress the process of differentiation and maturation of splenic lymphocyte and reticular cells, and 5-fluorouracil was more harmful on the spleen than mitomycin C. Whereas AG60 does not affect remarkably the process of differentiation and maturation of lymphocytes and reticular cells in the splenic white pulp.