Histopathological and parasitological study of the gastrointestinal tract of dogs naturally infected with Leishmania infantum.

BACKGROUND: The aim of this study was to provide a systematic pathological and parasitological overview of the gastrointestinal tract (GIT), including the stomach, duodenum, jejunum, ileum, caecum and colon, of dogs naturally infected with Leishmania. METHODS: Twenty mongrel dogs naturally infected with Leishmania (Leishmania) infantum and obtained from the Control Zoonosis Center of the Municipality of Ribeirão das Neves, Belo Horizonte Metropolitan area, Minas Gerais (MG) state, Brazil, were analyzed. The dogs were divided into two groups: Group 1 comprised nine clinically normal dogs and group 2 comprised 11 clinically affected dogs. After necropsy, one sample was collected from each GIT segment, namely the stomach, duodenum, jejunum, ileum, caecum and colon. Furthermore, paraffin-embedded samples were used for histological and parasitological (immunohistochemistry) evaluation and a morphometrical study were carried out to determine the parasite load (immunolabeled amastigote forms of Leishmania). The Friedman and the Mann Whitney tests were used for statistical analysis. The Friedman test was used to analyze each segment of the GIT within each group of dogs and the Mann Whitney test was used to compare the GIT segments between clinically unaffected and affected dogs. RESULTS: The infected dogs had an increased number of macrophages, plasma cells and lymphocytes, but lesions were generally mild. Parasite distribution in the GIT was evident in all intestinal segments and layers of the intestinal wall (mucosal, muscular and submucosal) irrespective of the clinical status of the dogs. However, the parasite load was statistically higher in the caecum and colon than in other segments of the GIT. CONCLUSION: The high parasite burden evident throughout the GIT mucosa with only mild pathological alterations led us to consider whether Leishmania gains an advantage from the intestinal immunoregulatory response (immunological tolerance).

Modulação da inflamação por ômega-3/6 / Modulation of the inflammation caused by Omega -3/6

Vários estudos vêm demonstrando os efeitos benéficos dos ácidos graxos poliinsaturados, especialmente do tipo ômega-3, no processo inflamatório. Esses lipídios, por meio de interferências na regulação gênica e no metabolismo celular, desempenham um papel modulador das reações in amatórias agudas ou crônicas. Neste trabalho, utilizou-se o modelo inflamatório induzido por implantes subcutâneos de parafina afim de avaliar os efeitos da administração dos ácidos graxos poliinsaturados por via oral e subcutânea. Foram utilizados camundongos Swiss, fêmeas, com 6 a 8 semanas de idade. Posteriormente, os animais receberam um implante subcutâneo de tabletes de parafina afim de induzir um processo inflamatório crônico. Vinte e um dias após a indução da inflamação, os animais receberam 100μl/camundongo de óleo de peixe contendo 180mg de ácido eicosapentaenóico e 120mg de ácido docosahexaenóico via oral. Pela via subcutânea, foram inoculados 20μl/camundongo de óleo de peixe contendo 3,6mg de ácido eicosapentaenóico e 2,4mg de ácido docosahexaenóico. Os camundongos receberam 8 (1 vez/semana) ou 24 (3 vezes/semana) inoculações, dependendo do experimento. O grupo controle (n = 5) recebeu tratamento com salina...

Several studies show that omega-3 polyunsaturated fatty acids suppress the immune response and inflammation. Some of the effects of omega-3 are brought about by modulation of the amount and types of eicosanoids made, and other effects are elicited by eicosanoid-in dependent mechanisms, including actions up on intracellular signaling pathways, transcription factor activity and gene expression. The aim of this study was to evaluate the effect of oral or subcutaneous omega-3 administration in chronic pathological conditions advancing.To determine whether chronic inflammation induced by paraffin implants is altered by w-3 supplementation, six to eight-week-old male Swiss (n = 5)...