The feline leukemia virus (FeLV) is a complex disease that affects mainly the immune and hematological systems of cats. And because the thymus was closely associated with the immune system, the aim of this study was t...The feline leukemia virus (FeLV) is a complex disease that affects mainly the immune and hematological systems of cats. And because the thymus was closely associated with the immune system, the aim of this study was to quantify the morphological changes in the thymus of naturally infected and uninfected animals. Thymus morphological changes were evaluated by quantifying the following parameters: thymocytes, fat tissue, thymic corpuscles, connective tissue, and type I and III collagen. This study analyzed a total of seven cats, five in the negative group (Fn) and two in the positive (Fp) group. The areas occupied by thymocytes in FeLV negative (Fn) and positive (Fp) animals were, respectively, 55.16% ± 6.15% and 44.81% ± 6.15% (p = 0.39);adipocytes, 42.14% ± 5.97% (Fn) and 53.42% ± 11.3% (Fp) (p = 0.34);blood vessels, 0.85% ± 0.24% (Fn) and 1.75% ± 0.52% (Fp) (p = 0.15). Whereas thymic corpuscles occupied an area of 0.68% ± 0.19% in negative animals (Fn) only. The connective tissue covered area varied between 12.05% ± 0.68% (Fn) and 10.34% ± 0.62% (Fp) (p = 0.009). Collagen type I (p = 0.30) and type III (p = 0.59) were present in, respectively, 1.73% ± 0.3% and 0.44% ± 0.09% in Fn, and 1.44% ± 0.36 and 0.44% ± 0.13% in Fp. The FeLV virus was not able to completely modify the thymus structure of infected animals, considering the areas occupied by thymocytes, adipose tissue, blood vessels and also type I and III collagens. However, the connective tissue underwent a certain degree of remodeling since less connective tissue area was observed in FeLV infected animals. The absence of thymic corpuscles in immunosuppressed animals suggests a possible connection to thymopoiesis.展开更多
Given the importance of the thymus to the immune system and the limited knowledge about its development and involution processes, this study evaluated the expression of the vascular endo-thelial growth factor, a key a...Given the importance of the thymus to the immune system and the limited knowledge about its development and involution processes, this study evaluated the expression of the vascular endo-thelial growth factor, a key angiogenic factor for the formation of vascular tissue bed and modulation of functions related to cell proliferation and migration, hormone synthesis, and immunomodulation. In this study, thymus samples of dog fetuses (30, 40, 50 and 60 days old), and young (180 days old) and adult (365 days old) dogs were submitted to real-time PCR and Western blot. Time-dependent changes were observed for proteins and genes associated with the development of the vascular system, such as VEGF-A, VEGF-C, Flt-1, KDR, FLT-4, and EG-VEGF. This result demonstrates that these system components play different roles during development and involution of the thymus. Possible functions, such as the modulatory effect on vasculogenesis and microenvironment, influence the proliferation and differentiation of thymocytes, T cells maturation, cell-cell interaction and hormone secretion.展开更多
文摘The feline leukemia virus (FeLV) is a complex disease that affects mainly the immune and hematological systems of cats. And because the thymus was closely associated with the immune system, the aim of this study was to quantify the morphological changes in the thymus of naturally infected and uninfected animals. Thymus morphological changes were evaluated by quantifying the following parameters: thymocytes, fat tissue, thymic corpuscles, connective tissue, and type I and III collagen. This study analyzed a total of seven cats, five in the negative group (Fn) and two in the positive (Fp) group. The areas occupied by thymocytes in FeLV negative (Fn) and positive (Fp) animals were, respectively, 55.16% ± 6.15% and 44.81% ± 6.15% (p = 0.39);adipocytes, 42.14% ± 5.97% (Fn) and 53.42% ± 11.3% (Fp) (p = 0.34);blood vessels, 0.85% ± 0.24% (Fn) and 1.75% ± 0.52% (Fp) (p = 0.15). Whereas thymic corpuscles occupied an area of 0.68% ± 0.19% in negative animals (Fn) only. The connective tissue covered area varied between 12.05% ± 0.68% (Fn) and 10.34% ± 0.62% (Fp) (p = 0.009). Collagen type I (p = 0.30) and type III (p = 0.59) were present in, respectively, 1.73% ± 0.3% and 0.44% ± 0.09% in Fn, and 1.44% ± 0.36 and 0.44% ± 0.13% in Fp. The FeLV virus was not able to completely modify the thymus structure of infected animals, considering the areas occupied by thymocytes, adipose tissue, blood vessels and also type I and III collagens. However, the connective tissue underwent a certain degree of remodeling since less connective tissue area was observed in FeLV infected animals. The absence of thymic corpuscles in immunosuppressed animals suggests a possible connection to thymopoiesis.
文摘Given the importance of the thymus to the immune system and the limited knowledge about its development and involution processes, this study evaluated the expression of the vascular endo-thelial growth factor, a key angiogenic factor for the formation of vascular tissue bed and modulation of functions related to cell proliferation and migration, hormone synthesis, and immunomodulation. In this study, thymus samples of dog fetuses (30, 40, 50 and 60 days old), and young (180 days old) and adult (365 days old) dogs were submitted to real-time PCR and Western blot. Time-dependent changes were observed for proteins and genes associated with the development of the vascular system, such as VEGF-A, VEGF-C, Flt-1, KDR, FLT-4, and EG-VEGF. This result demonstrates that these system components play different roles during development and involution of the thymus. Possible functions, such as the modulatory effect on vasculogenesis and microenvironment, influence the proliferation and differentiation of thymocytes, T cells maturation, cell-cell interaction and hormone secretion.
