RESUMO
The peripheral nervous system lacks lymphatic vessels and is protected by the blood-nerve barrier, which prevents lymphocytes and antibodies from entering the neural parenchyma. Peripheral nerve injury results in degeneration of the distal nerve and myelin degeneration causes macrophage aggregation, T lymphocyte infiltration, major histocompatibility complex class II antigen expression, and immunoglobulin G deposition in the nerve membrane, which together result in nerve edema and therefore affect nerve regeneration. In the present paper, we show myelin expression was absent from the sciatic nerve at 7 days after injury, and the expression levels of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) and Prospero Homeobox 1 (Prox1) were significantly increased in the sciatic nerve at 7 days after injury. The lymphatic vessels were distributed around the myelin sheath and co-localized with lymphatic endothelial cells. Prox1 induces the formation of new lymphatic vessels, which play important roles in the elimination of tissue edema as well as in morphological and functional restoration of the damaged nerve. This study provides evidence of the involvement of new lymphatic vessels in nerve repair after sciatic nerve injury.
Assuntos
Proteínas de Homeodomínio/metabolismo , Linfangiogênese , Regeneração Nervosa , Traumatismos dos Nervos Periféricos/metabolismo , Nervo Isquiático/lesões , Proteínas Supressoras de Tumor/metabolismo , Animais , Modelos Animais de Doenças , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Bainha de Mielina/metabolismo , Compressão Nervosa , Traumatismos dos Nervos Periféricos/patologia , Distribuição Aleatória , Nervo Isquiático/metabolismo , Nervo Isquiático/patologiaRESUMO
We investigated the distribution and formation of new lymphatic vessels in gliomas. Specimens from seven glioma cases were analyzed by immunohistochemical staining for CD34, lymphatic endothelial hyaluronic acid receptor 1 (LYVE-1), prospero-related homeobox 1 (Prox1), nestin, and hypoxia-inducible factor 1α (HIF-1α). Three types of vessels were observed in glioma specimens: LYVE-1+ lymphatic vessels, CD34+ blood vessels, and LYVE-1+ /CD34+ blood vessels. Prox1+ /LYVE-1+ cells were distributed in some lymphatic vessels as well as among vascular endothelial cells and glioma cells. Nestin+ cells were scattered throughout the gliomas, and some lymphatic cells also expressed nestin. HIF-1α+ Prox1+ cells were widely distributed within the glioma specimens. The present immunohistochemical analysis revealed upregulation of Prox1 and HIF-1α in some glioma tissues as well as the differentiation of nestin+ tumor stem cells into LYVE-1+ lymphatic vessels.