Immunohistochemical detection of pro-inflammatory and anti-inflammatory cytokines in granulomas in cattle with natural Mycobacterium bovis infection.

Cellular immune response was evaluated in lymph nodes and lung with different granulomatous lesions from cattle naturally infected with Mycobacterium bovis. For this purpose, we assessed pro-inflammatory and anti-inflammatory cytokines by immunohistochemical assays. Immunoreaction was observed for all the cytokines analyzed. Fourteen animals displayed advanced stage IV granulomas, with intense immunoreactivity to IFN-γ and TGF-ß in areas of caseous necrosis, macrophages and lymphocytes. Seven animals showed stage III granuloma, with high immunoreactivity to IFN-γ (average of 44.5% immunoreactive cells) and moderate to TNF-α and to the anti-inflammatory cytokines IL-10 and TGF-ß, in relation to the proliferation of fibroblasts in granuloma periphery We found satellite stage I granulomas in 4 bovines and stage II granulomas in 2 bovines, which exhibited low immunostaining response (-13%). Cytokine expression in stage III and IV granulomas was significant, with predominance of immunoreactivity to IFN-γ, thus suggesting a strong, longstanding local immune response mediated by macrophages and epithelioid cells. In addition, these two stages displayed lower reactivity to IL-10; which suggests a deficit of anti-inflammatory cytokines, suppressed immunity and persistence of the infection. High expression of TGF-ß could indicate a chronic process with greater tissue damage and fibrosis. Numerous bacilli observed in necrotic areas in stage III and IV granulomas with low expression of IL-1ß suggest failure in the immune response with bacterial multiplication. In this study, evidence of in situ presence of cytokines demonstrates these cytokines are involved in the development and evolution of bovine tuberculosis granulomas.

Association between spoligotype-VNTR types and virulence of Mycobacterium bovis in cattle.

Mycobacterium bovis is the causative agent of bovine tuberculosis, a disease that affects approximately 5% of Argentine cattle. The aim of this research was to study if it is possible to infer the degree of virulence of different M. bovis genotypes based on scorified observations of tuberculosis lesions in cattle. In this study, we performed association analyses between several parameters with tuberculosis lesions: M. bovis genotype, degree of progression of tuberculosis, and animal age. For this purpose, the genotype was determined by spoligotyping and the degree of bovine tuberculosis gross lesion was quantified with a score based on clinical observations (number, size, and location of granulomas along with histopathologic features). This study was performed with naturally infected cattle of slaughterhouses from three provinces in Argentina. A total of 265 M. bovis isolates were obtained from 378 pathological lesion samples and 192 spoligotyping and VNTR (based on ETR sequences) typing patterns were obtained. SB0140 was the most predominant spoligotype, followed by SB0145. The spoligotype with the highest lesion score was SB0273 (median score of 27 ± 4.46), followed by SB0520 (18 ± 5.8). Furthermore, the most common spoligotype, SB0140, had a median score of 11 ± 0.74. Finally, the spoligotype with the lowest score was SB0145 (8 ± 1.0). ETR typing of SB0140, SB0145, SB0273, and SB0520 did not subdivide the lesion scores in those spoligotypes. In conclusion, SB0273 and SB0520 were the spoligotypes with the strongest association with hypervirulence and both spoligotypes were only found in Río Cuarto at the south of Córdoba province. Interestingly, there is no other report of any of these spoligotyes in Latin America.

Mycobacterium intracellulare infection in a capybara (Hydrochoerus hydrochaeris).

This report describes the first case of Mycobacterium intracellulare infection with typical granulomatous lesions of mycobacteriosis in a capybara (Hydrochoerus hydrochaeris). The individual was a captive-bred young female, part of the control group of an experimental study on stress. Multiple granulomatous lesions were detected in a mesenteric lymph node of this young female. Mycobacterial infection was confirmed by bacteriologic culture and molecular identification methods. Clinical lesions were characterized by histopathology.

Microscopic characterization of follicular structures in letrozole-induced polycystic ovarian syndrome in the rat.

BACKGROUND: Our objective was to characterize the tissular distribution of relevant cytoskeletal proteins, cellular adhesion molecules and proliferation markers and conduct a histomorphometrical study of the follicular wall of letrozole-induced polycystic ovaries. METHODS: Twenty rats were divided into two groups: a control group (C) of ten rats that received vehicle only (0.9% NaCl solution) once daily p.o. and a treatment group (T) of ten animals administered letrozole at a concentration of 1 mg/kg p.o. dissolved in 0.9% NaCl solution once daily during 21 days. Twenty four h after the last administration, all animals were sacrificed. Control animals were sacrificed in proestrous (n = 5) and diestrous (n = 5). Serum hormone levels, histomorphometrical changes and immunoexpression of intermediate filaments (vimentin, cytokeratins and desmin), cadherins and proliferation cellular nuclear antigen were examined. RESULTS: The granulosa cell layer of cystic follicles had a greater significant immunostaining for vimentin and cytokeratins. Immunohistochemical localization of desmin was restricted to the theca externa. Positive immunoreactivity for cadherins rises gradually and significantly, together with the follicular development, and immunoreactivity was comparatively stronger in follicular cysts. A significantly higher immunostaining for PCNA cells was observed in secondary and tertiary follicles as compared with atretic and cystic follicles. An increase in the LH, FSH and testosterone serum concentrations was observed in letrozole-treated rats. Estradiol and progesterone showed a considerable reduction. CONCLUSIONS: The changes observed are probably due to structural and functional alterations that occur during the process of cystogenesis and may be associated with important modifications in the expression of cytoskeletal proteins, cellular adhesion molecules and proliferation markers that may be essential for proper cellular functioning.