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The lymphatic vascular system of the mouse head

View Article: PubMed Central - PubMed

ABSTRACT

Histological studies of the lymphatic vascular system in adult mice are hampered because bones cannot be sectioned properly. Here, we decalcified the heads of 14-day-old mice, embedded them in paraffin and stained resultant serial sections with the lymphendothelial-specific antibodies Lyve-1 and Podoplanin. We show that the tissues with the highest lymphatic vascular density are the dermis and the oral mucous membranes. In contrast, the nasal mucous membrane is devoid of lymphatics, except for its most basal parts below the vomeronasal organ. The inferior nasal turbinate contains numerous lymphatics and is connected to the nasolacrimal duct (NLD), which is ensheathed by a dense network of lymphatics. The lymphatics of the eye lids and conjunctiva are connected to those of the inferior nasal turbinate. We suggest that cerebro-spinal fluid (CSF) can drain via the optic nerve and NLD lymphatics, whereas CSF drained via the Fila olfactoria into the nasal mucous membrane is used for moisturization of the respiratory air. Tongue, palatine and buccal mucous membranes possess numerous lymphatics, whereas the dental pulp has none. Lymphatics are present in the maxillary gland and close to the temporomandibular joint, suggesting the augmentation of lymph flow by chewing and yawning. Lymphatics can also be found in the dura mater and in the dural septae entering into deeper parts of the brain. Our findings are discussed with regard to CSF drainage and potential routes for ocular tumor dissemination.

No MeSH data available.


Lyve-1 expression in dendritic cells, high endothelial venules (HEVs) and LECs. a Lymph node (ln) located between the parotis (pa) and the submandibular gland (smg). Magnification ×40. Bar 200 μm. b Lymph node showing Lyve-1 expression in HEVs (hev). Magnification ×200. Bar 50 μm. c Anti-podoplanin staining of the same lymph node as that in b. Note the podopanin+ reticular cells and podoplanin+ sinuses. Magnification ×100. Bar 100 μm. d Immunofluorescence staining of a lymph node with the antibodies anti-Lyve-1 (green) and anti-podoplanin (red). Note the Lyve-1+/Podoplanin+ visceral layer (vl) and the Lyve-1−/Podoplanin+ parietal layer (pl). Magnification ×400. Bar 20 μm
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Fig2: Lyve-1 expression in dendritic cells, high endothelial venules (HEVs) and LECs. a Lymph node (ln) located between the parotis (pa) and the submandibular gland (smg). Magnification ×40. Bar 200 μm. b Lymph node showing Lyve-1 expression in HEVs (hev). Magnification ×200. Bar 50 μm. c Anti-podoplanin staining of the same lymph node as that in b. Note the podopanin+ reticular cells and podoplanin+ sinuses. Magnification ×100. Bar 100 μm. d Immunofluorescence staining of a lymph node with the antibodies anti-Lyve-1 (green) and anti-podoplanin (red). Note the Lyve-1+/Podoplanin+ visceral layer (vl) and the Lyve-1−/Podoplanin+ parietal layer (pl). Magnification ×400. Bar 20 μm

Mentions: As previously indicated, the oral mucous membrane possesses a dense network of initial lymphatics that can be found in all its regions including its gingival, buccal and palatinal aspects (Fig. 1a,b). In the tongue, these lymphatics are situated immediately beneath the epithelial layer, both at the back of the tongue and in its floor. Additionally, the tongue muscle contains numerous lymphatics that most likely drain into collectors accompanying the lingual artery (Fig. 1a-c). Interestingly, the dental pulp is free of lymphatics (Fig. 1a) but lymphatics can be found accompanying the inferior alveolar artery and nerve (Fig. 1d). Although we did not find any lymphatics in the dental pulp, we observed ramified cells weakly positive for Lyve-1, which might have represented dendritic cells or macrophages (Fig. 1e). At the floor of the mouth, lymph nodes are found in between the submandibular and parotid glands (Fig. 2a). These murine lymph nodes possess a marginal sinus. However, although both layers were Podoplanin-positive (Fig. 2c), only the visceral layer of the sinus was Lyve-1-positive, whereas the parietal layer was mostly Lyve-1-negative (Fig. 2d). Trabecular sinuses, as found in human lymph nodes, are not present. In the center of the lymph nodes, high endothelial venules (HEVs) are found to be weakly positive for Lyve-1 (Fig. 2b). Reticular cells are detectable as being Podoplanin-positive (Fig. 2c). We found more lymphatics in the submandibular gland as compared with the parotis and these lymphatics were usually located adjacent to the intra- and interlobular excretory ducts (data not shown). Lymphatics were also located in close proximity to the temporomandibular joint, suggesting a function for the uptake of synovial fluid. Contrarily, the number of lymphatics in the masseteric muscle was very low (data not shown).Fig. 1


The lymphatic vascular system of the mouse head
Lyve-1 expression in dendritic cells, high endothelial venules (HEVs) and LECs. a Lymph node (ln) located between the parotis (pa) and the submandibular gland (smg). Magnification ×40. Bar 200 μm. b Lymph node showing Lyve-1 expression in HEVs (hev). Magnification ×200. Bar 50 μm. c Anti-podoplanin staining of the same lymph node as that in b. Note the podopanin+ reticular cells and podoplanin+ sinuses. Magnification ×100. Bar 100 μm. d Immunofluorescence staining of a lymph node with the antibodies anti-Lyve-1 (green) and anti-podoplanin (red). Note the Lyve-1+/Podoplanin+ visceral layer (vl) and the Lyve-1−/Podoplanin+ parietal layer (pl). Magnification ×400. Bar 20 μm
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Related In: Results  -  Collection

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Fig2: Lyve-1 expression in dendritic cells, high endothelial venules (HEVs) and LECs. a Lymph node (ln) located between the parotis (pa) and the submandibular gland (smg). Magnification ×40. Bar 200 μm. b Lymph node showing Lyve-1 expression in HEVs (hev). Magnification ×200. Bar 50 μm. c Anti-podoplanin staining of the same lymph node as that in b. Note the podopanin+ reticular cells and podoplanin+ sinuses. Magnification ×100. Bar 100 μm. d Immunofluorescence staining of a lymph node with the antibodies anti-Lyve-1 (green) and anti-podoplanin (red). Note the Lyve-1+/Podoplanin+ visceral layer (vl) and the Lyve-1−/Podoplanin+ parietal layer (pl). Magnification ×400. Bar 20 μm
Mentions: As previously indicated, the oral mucous membrane possesses a dense network of initial lymphatics that can be found in all its regions including its gingival, buccal and palatinal aspects (Fig. 1a,b). In the tongue, these lymphatics are situated immediately beneath the epithelial layer, both at the back of the tongue and in its floor. Additionally, the tongue muscle contains numerous lymphatics that most likely drain into collectors accompanying the lingual artery (Fig. 1a-c). Interestingly, the dental pulp is free of lymphatics (Fig. 1a) but lymphatics can be found accompanying the inferior alveolar artery and nerve (Fig. 1d). Although we did not find any lymphatics in the dental pulp, we observed ramified cells weakly positive for Lyve-1, which might have represented dendritic cells or macrophages (Fig. 1e). At the floor of the mouth, lymph nodes are found in between the submandibular and parotid glands (Fig. 2a). These murine lymph nodes possess a marginal sinus. However, although both layers were Podoplanin-positive (Fig. 2c), only the visceral layer of the sinus was Lyve-1-positive, whereas the parietal layer was mostly Lyve-1-negative (Fig. 2d). Trabecular sinuses, as found in human lymph nodes, are not present. In the center of the lymph nodes, high endothelial venules (HEVs) are found to be weakly positive for Lyve-1 (Fig. 2b). Reticular cells are detectable as being Podoplanin-positive (Fig. 2c). We found more lymphatics in the submandibular gland as compared with the parotis and these lymphatics were usually located adjacent to the intra- and interlobular excretory ducts (data not shown). Lymphatics were also located in close proximity to the temporomandibular joint, suggesting a function for the uptake of synovial fluid. Contrarily, the number of lymphatics in the masseteric muscle was very low (data not shown).Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Histological studies of the lymphatic vascular system in adult mice are hampered because bones cannot be sectioned properly. Here, we decalcified the heads of 14-day-old mice, embedded them in paraffin and stained resultant serial sections with the lymphendothelial-specific antibodies Lyve-1 and Podoplanin. We show that the tissues with the highest lymphatic vascular density are the dermis and the oral mucous membranes. In contrast, the nasal mucous membrane is devoid of lymphatics, except for its most basal parts below the vomeronasal organ. The inferior nasal turbinate contains numerous lymphatics and is connected to the nasolacrimal duct (NLD), which is ensheathed by a dense network of lymphatics. The lymphatics of the eye lids and conjunctiva are connected to those of the inferior nasal turbinate. We suggest that cerebro-spinal fluid (CSF) can drain via the optic nerve and NLD lymphatics, whereas CSF drained via the Fila olfactoria into the nasal mucous membrane is used for moisturization of the respiratory air. Tongue, palatine and buccal mucous membranes possess numerous lymphatics, whereas the dental pulp has none. Lymphatics are present in the maxillary gland and close to the temporomandibular joint, suggesting the augmentation of lymph flow by chewing and yawning. Lymphatics can also be found in the dura mater and in the dural septae entering into deeper parts of the brain. Our findings are discussed with regard to CSF drainage and potential routes for ocular tumor dissemination.

No MeSH data available.