We investigated the expression and localization of connexins (CX) 26 and 43 in the rat gingival epithelium. RT-PCR analysis revealed CX26 gene expression in both the upper and lower layers of the gingival epithelium and in the total epithelial layer, whereas CX43 gene expression was limited to the lower layer and the total epithelial layer. Immunoreactivity for CX43 was observed in the membranes of adjacent cells from the basal layer to the middle of the prickle cell layer, while immunoreactivity for CX26 was observed in the granular cell layer and lower part of the squamous cell layer. Merged images revealed the co-localization of CX26 and CX43 in the middle of the prickle cell layer. By immuno-electron microscopy, gap junctions appeared curved, hemi-circular, or annular within the cytoplasm, and gold particles indicating the presence of CX43 were localized at the outer edges of these cytoplasmic formations. These results suggest that CX43 is associated with the regulation of cell proliferation and that increased CX26 expression is associated with differentiation of keratinocytes. Thus, degradation of CX43 is considered to play an essential role in differentiation of the rat gingival epithelium.

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This study used 100-μm thick paraffin sections stained by the ER-HR3 antibody to examine the three-dimensional surface morphology of the central macrophages of erythroblastic islets in the splenic red pulp of aged and pregnant mice. The ER-HR3-positive cells were the macrophages located at the center of the erythroblastic islets, and the number per unit of splenic area was almost constant until 30 days of age, thereafter showing a marked decrease. In pregnant females, the ER-HR3-positive macrophage number significantly increased and became approximately eight times higher than the control value. In aged virgin females, the islet macrophages were generally ovoid in cell profile, and shallow cup-shaped dents were formed on their cell surface. However, in pregnant females, the macrophages became larger in size, and cell socket structures, formed by long finger-like cytoplasmic processes, became prominent on their cell surface. The 3-D images, obtained from 100-μm thick paraffin sections, provided the clear morphological evidence of the activity of the islet macrophages in spleen erythropoiesis.

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The inhibition of apoptosis by glycyrrhizin (GL) in hepatic injury induced by injection of lipopolysaccharide (LPS)/D-galactosamine (D-GalN) was examined in the present study. Morphological and biochemical analyses of LPS/D-GalN-induced mouse liver injury revealed that apoptosis occurred exclusively in injured hepatocytes of the centrilobular area. The degree of hepatic injury was associated with a substantial number of hepatocytes undergoing apoptosis. Transaminase levels were significantly increased at 6 to 8 h after the injection of LPS/D-GalN compared with controls. GL inhibited the elevation of serum transaminase levels when it was given to mice at 30 min before the administration of LPS/D-GalN. Morphological analyses using the TUNEL-method showed GL significantly reduced the number of TUNEL-labeled cells in acute hepatitis induced with LPS/D-GalN-treatment. Cells from the pericentral hepatic injury region were dissected out using a microdissection-method, and the DNA-ladder was clearly documented. Furthermore, results obtained through the TUNEL-method were confirmed with an oligonucleosome-bound DNA ELISA. From the current results, it seems reasonable to conclude that the protective role of GL in LPS/D-GalN-induced liver injury is performed through the inhibition of hepatic apoptosis.

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Protease-activated receptors (PARs) expressed in the endothelia and smooth muscles of vessels may play important roles in blood vessel function. Using intracellular calcium ion concentration ([Ca²⁺]_i) imaging, we recently observed that small - but not large - arterioles of the brain responded to proteases, while testicular arterioles showed no response. The purpose of the present study was to examine the heterogeneity of the localization of PARs in arterioles using immunohistochemistry. Consistent with the [Ca²⁺]_i imaging results, neither the thrombin receptor nor PAR2 were evident in large arterioles of the brain. However, the small arterioles of the brain, vascular smooth muscles, and endothelia showed a distinct immunoreactivity against the thrombin receptor and PAR2. The immunoreactivity of PARs in testicular arterioles was faint. In conclusion, size-dependent and/or organ-specific responses of arterioles to proteases are due to the heterogeneous localization of PARs.

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In the present study, we have analyzed the α(IV) chain distribution in the subepithelial basement membrane (BM) of the rat pulmonary airway from the bronchi to alveoli. We have furthermore analyzed the α(IV) chain distribution in the subepithelial BM of the bronchioalveolar duct junction (BADJ) using α(IV) chain specific monoclonal antibodies. Our results show that the BM of the bronchial and bronchiolar epithelium contains [α1(IV)]₂α2(IV) and [α5(IV)]₂α6(IV) molecules and confirmed that the alveolar BM consists of [α1(IV)]₂α2(IV) and α3(IV) α4(IV)α5(IV) molecules. There are also small regions in BADJ consisting of only [α1(IV)]₂α2(IV) molecules without α3(IV)α4(IV)α5(IV) and [α5(IV)]₂α6(IV) molecules. Moreover, the bronchioalveolar stem cells (BASCs)-primordial cells for bronchiolar Clara cells and alveolar type II (AT2) cells - lie adjacent to such small regions. These findings suggest that [α1(IV)]₂ α2(IV) may be important for the BASCs to self-renew or to self-maintain themselves and that microenvironments produced by α(IV) chains may be important for cell differentiation.

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The aim of the current study was to investigate the specific accumulation of the Sialyl Lewis X (SLX) liposome in inflammation in the collagen-antibody induced arthritic (CAIA) model mice. The SLX-liposome encapsulating fluorescent substance (Cy5.5 or Cy3) was prepared for this study. The SLX-liposome was administered intravenously via the mouse caudal vein. After 1 to 24 h, the accumulation of SLX-liposome was observed using in vivo fluorescent imaging equipment (eXplore Optix), or the knee joints were removed for histological analysis. The in vivo fluorescent imaging showed that the signal was confined to the inflammatory site in the CAIA mice in an inflammatory dependent manner. The signal intensity was stronger at 24 h than at 1 h after injection. In the histological sections, the fluorescent signals were detected in the periarticular soft-tissue, especially in the hyperplastic synovium, including a pannus invasion with inflammatory cells in the CAIA. Intense signals were observed in vessel-like structures 1 h after injection; these were co-labeled with the vascular endothelial cell marker (CD31) and E-selectin, a ligand of the SLX-liposome expressed on activated endothelial cells. The diffused signals from the vessels increased time-dependently at 6 to 24 h after injection. This is the first report to examine the exact localization of the SLXliposome by encapsulated fluorescence in hyperplastic synovial tissue of CAIA mice. These results suggest the feasibility and potential use of SLX-liposome as a vehicle for the active targeting of drug delivery to inflammatory tissue.

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