Resumo
Background: Colitis murine models have become essential tools to investigate the molecular and cellular mechanisms that lead to infl ammatory bowel disease (IBD), such as ulcerative colitis (UC). DSS-induced colitis model faithfully reproduces many of the clinical presentation and immunological disturbances observed in UC. Notwithstanding mice can show differential susceptibilities and responsiveness to dextran sodium sulfate (DSS), and varying DSS concentration and molecular weights appear to be associated with the severity of inflammation. The aim of this study was to analyze the features of mice induced colitis using different DSS concentrations and molecular weights. Materials, Methods and Results: C57BL/6 mice received 2% of high molecular weight DSS (36 000 - 50 000) in drinking water (HDSS2%) or 5% of the same molecular weight (HDSS5%); other group received 5% of low molecular weight DSS (10 000) (LDSS5%). During the 7 days of DSS administration, animals were observed for weight loss, stool consistency and presence of blood feces to determine the disease activity index (DAI). On day 8, colons were removed, measured and weighed for indirect assessment of infl ammation. The tissue samples were processed for histological analysis and blood samples were collected for hematological analysis. Our results demonstrated that HDSS5% group began to show significant clinical signs starting from day 1, HDSS2% on day 2 and LDSS5% on day 3 (P < 0.05). However, from day 3, HDSS5% group presented DAI significantly higher than other groups (P < 0.001). In addition, DSS administration for 7 days was associated with significant (P < 0.05) changes in mice body weight compared to control animals. Group HDSS2% showed a weight loss of 23.8%±3.0, and HDSS5% and LDSS5% groups, presented weight loss of 32.65%±0.0 and 8.7%±1.7, respectively. From day 6, HDSS5% group presented weight loss significantly greater than HDSS2% and LDSS5% groups (P < 0.05). In colon macroscopic analysis, high molecular weight DSS groups showed a significantly macroscopic colon changes (P = 0.001) and hematological parameters alteration (P < 0.005) compared to control group. In histological features of colitis, these groups presented a higher histological score compared to normal colon (P < 0.001), with crypt damage, mucosal ulceration and cell inflammatory infiltration. Mice from group LDSS5% did not present significant macroscopic colon changes, hematological parameters alteration, and histological score compared to control group. Discussion: Results of the present study evidenced that acute colonic mucosal injury induced by DSS is dependent on the concentration and molecular weight of DSS administered in drinking water, and these findings are important consideration for reproducible induction of experimental colitis with this model. Moreover, DSS with high molecular weight and high concentration can initiate a severe colitis, which may not be an appropriate model for studies of therapeutic regeneration of the colonic mucosa. Thus, identification of differences in mice response to DSS could provide the basis for investigations of susceptibility or resistance to colitis. DSS-induced colitis model study contributes to the understanding of IBD and in the finding for new therapies targeting the reduction of inflammation.
Assuntos
Animais , Masculino , Camundongos , Colite Ulcerativa/induzido quimicamente , Sulfato de Dextrana/efeitos adversosResumo
Background: Colitis murine models have become essential tools to investigate the molecular and cellular mechanisms that lead to inflammatory bowel disease (IBD), such as ulcerative colitis (UC). DSS-induced colitis model faithfully reproduces many of the clinical presentation and immunological disturbances observed in UC. Notwithstanding mice can show differential susceptibilities and responsiveness to dextran sodium sulfate (DSS), and varying DSS concentration and molecular weights appear to be associated with the severity of inflammation. The aim of this study was to analyze the features of mice induced colitis using different DSS concentrations and molecular weights. Materials, Methods and Results: C57BL/6 mice received 2% of high molecular weight DSS (36 000 - 50 000) in drinking water (HDSS2%) or 5% of the same molecular weight (HDSS5%); other group received 5% of low molecular weight DSS (10 000) (LDSS5%). During the 7 days of DSS administration, animals were observed for weight loss, stool consistency and presence of blood feces to determine the disease activity index (DAI). On day 8, colons were removed, measured and weighed for indirect assessment of inflammation. The tissue samples were processed for histological analysis and blood samples were collected for hematological analysis. Our results demonstrated that HDSS5% group began to show significant clinical signs sta
Background: Colitis murine models have become essential tools to investigate the molecular and cellular mechanisms that lead to inflammatory bowel disease (IBD), such as ulcerative colitis (UC). DSS-induced colitis model faithfully reproduces many of the clinical presentation and immunological disturbances observed in UC. Notwithstanding mice can show differential susceptibilities and responsiveness to dextran sodium sulfate (DSS), and varying DSS concentration and molecular weights appear to be associated with the severity of inflammation. The aim of this study was to analyze the features of mice induced colitis using different DSS concentrations and molecular weights. Materials, Methods and Results: C57BL/6 mice received 2% of high molecular weight DSS (36 000 - 50 000) in drinking water (HDSS2%) or 5% of the same molecular weight (HDSS5%); other group received 5% of low molecular weight DSS (10 000) (LDSS5%). During the 7 days of DSS administration, animals were observed for weight loss, stool consistency and presence of blood feces to determine the disease activity index (DAI). On day 8, colons were removed, measured and weighed for indirect assessment of inflammation. The tissue samples were processed for histological analysis and blood samples were collected for hematological analysis. Our results demonstrated that HDSS5% group began to show significant clinical signs sta
Resumo
Background: Biological membranes demonstrate superiority over synthetic ones for its biocompatibility and strength in the reduction of abdominal hernias. Recents tissue engineering researches add mesenchymal stem cells to biological membranes with the purpose of obtaining additional cellular proliferation and consequent muscle regeneration, using biological membranes as cellular scaffolds. This article aimed to study the influence of mesenchymal stem cells in muscle regeneration in abdominal hernias, reduced with biological membranes. Materials, Methods & Results: Adult Wistar rats underwent abdominal hernia-inducing. They were divided into two groups as to the form of treatment for the reduction of hernia: stem cells associated with biological membranes or only biological membranes. After the treatment the macro and microscopic reviews were carried out in days seven, 14 and 60 postoperatively. Preparation of bovine pericardium with glycerin 98% presented efficiency in decellularization and conservation, maintaining its strength and avoiding bacterial growth. The mesenchymal stem cells obtained from bone marrow of adult Wistar rats, had capacity of proliferation. The majority of the cells was positive for the expression of surface antigens CD44, CD29 and CD99 and was negative for CD 34. In the differentiation trials, the same cells were able to differentiate into adipocytes and osteocytes. With 24 h from co-cultivating adhesion of mesenchymal stem cells in the membranes was observed. There was no foreign body reaction or contamination of surgical wounds and there was intense postoperative neovascularization on seven days. All animals presented omentum adherence, but no adherence to other organs.There was no statistically difference for the different times in macroscopic assessment: deposition of fibrous tissue, implant integration. The same occurred with the microscopic evaluations between the different treatment groups. The groups of immediate and later repair presented different responses to treatment. Discussion: The use of rats as animal model was satisfactory, being suitable for surgical procedures and assessments of the abdominal cavity. The different results obtained between groups of immediate repair and late repair corroborate with the idea that there is difference between induction and repair models in the same surgery or in different surgeries with the time interval between the two, suggesting the need for methodologies that simulate the hernias chronicity. The cells used were classified as mesenchymal stem cells, because it met all the criteria of Mesenchymal and Tissue Stem Cell Committee of the International Society of Celullar Therapy. The membranes conserved with glycerin 98% demonstrated biocompatibility, because there was no rejection or necrosis, infection or exacerbated infl ammation. However the muscle regeneration was not obtained over the membranes - and the methodological difference in other latest experiments about the membranes decellularization and the co-cultivating - can leads to conclusion that the cells attached to membranes were insufficient in number to obtain the desired result. These results suggest the need of new research studies or co-cultivating times and decellularization methods of bovine pericardium for association with mesenchymal stem cells.
Assuntos
Animais , Masculino , Ratos , Pericárdio/transplante , Hérnia Abdominal/reabilitação , Hérnia Abdominal/veterinária , Células-Tronco Mesenquimais , Ratos WistarResumo
Background: Biological membranes demonstrate superiority over synthetic ones for its biocompatibility and strength in the reduction of abdominal hernias. Recents tissue engineering researches add mesenchymal stem cells to biological membranes with the purpose of obtaining additional cellular proliferation and consequent muscle regeneration, using biological membranes as cellular scaffolds. This article aimed to study the influence of mesenchymal stem cells in muscle regeneration in abdominal hernias, reduced with biological membranes. Materials, Methods & Results: Adult Wistar rats underwent abdominal hernia-inducing. They were divided into two groups as to the form of treatment for the reduction of hernia: stem cells associated with biological membranes or only biological membranes. After the treatment the macro and microscopic reviews were carried out in days seven, 14 and 60 postoperatively. Preparation of bovine pericardium with glycerin 98% presented efficiency in decellularization and conservation, maintaining its strength and avoiding bacterial growth. The mesenchymal stem cells obtained from bone marrow of adult Wistar rats, had capacity of proliferation. The majority of the cells was positive for the expression of surface antigens CD44, CD29 and CD99 and was negative for CD 34. In the differentiation trials, the same cells were able to differentiate into adipocytes
Vários tipos de implantes, naturais ou sintéticos, vêm sendo testados no reparo cirúrgico de hérnias. As membranas biológicas, ou arcabouços dérmicos descelularizados, apresentam reduzida formação de aderência entre o implante e as vísceras, diminuição da formação de fístulas, infecções e recorrências. Também apresentam resistência suficiente para suportar a pressão abdominal, evitando deiscências e eviscerações. [...]
Resumo
This study presents an experimental model of an acute deffect in a peripheral nerve to evaluate neural regeneration using a tubulization technique associated with the inoculation of autologous stem cells from bone marrow. A total of 12 New Zealand white rabbits underwent a bilateral dissection of the tibial nerve followed by repair with silicone tubulization. On the left tibial nerve of all animals, the tube was filled with autologous bone marrow-derived stem cells collected from the humerus. For control, using the same repair technique, the tubes were filled with a NaCl solution in the right tibial nerve. After 30 days of observation, the animals were euthanized and a histological evaluation of the collected nerve segments was performed by staining with hematoxylin-eosin, luxol fast blue, and toluidine blue. From the results it is possible to conclude that the transplanted autologous stem cells associated with the tubulization technique present an advantage in the peripheral nerve regeneration process.
Neste estudo é apresentado um modelo experimental de defeito agudo em nervo periférico para avaliação da regeneração nervosa mediante técnica de tubulização associada à inoculação de células-tronco autólogas de medula óssea. Foram utilizados 12 coelhos Nova Zelândia albinos, submetidos à secção bilateral e ao afastamento de 5mm do nervo tibial e posterior reparo mediante utilização de câmara de silicone. Internamente à prótese de tubulização do nervo tibial esquerdo em todos os animais, foram inoculadas células-tronco autólogas de medula óssea, coletadas a partir do úmero. Como grupo controle (nervo tibial direito), mediante aplicação da mesma técnica de reparo, solução de NaCl 0,9% foi administrada internamente à prótese. Após 30 dias de observação, os animais foram eutanasiados e foi realizada a avaliação histológica dos segmentos nervosos por meio das colorações de hematoxilina-eosina, luxol fast blue e azul de toluidina. Com os resultados, foi possível concluir que o transplante de células-tronco autólogas associado à técnica de tubulização apresenta vantagens no processo de regeneração nervosa periférica.
Resumo
This study presents an experimental model of an acute deffect in a peripheral nerve to evaluate neural regeneration using a tubulization technique associated with the inoculation of autologous stem cells from bone marrow. A total of 12 New Zealand white rabbits underwent a bilateral dissection of the tibial nerve followed by repair with silicone tubulization. On the left tibial nerve of all animals, the tube was filled with autologous bone marrow-derived stem cells collected from the humerus. For control, using the same repair technique, the tubes were filled with a NaCl solution in the right tibial nerve. After 30 days of observation, the animals were euthanized and a histological evaluation of the collected nerve segments was performed by staining with hematoxylin-eosin, luxol fast blue, and toluidine blue. From the results it is possible to conclude that the transplanted autologous stem cells associated with the tubulization technique present an advantage in the peripheral nerve regeneration process.
Neste estudo é apresentado um modelo experimental de defeito agudo em nervo periférico para avaliação da regeneração nervosa mediante técnica de tubulização associada à inoculação de células-tronco autólogas de medula óssea. Foram utilizados 12 coelhos Nova Zelândia albinos, submetidos à secção bilateral e ao afastamento de 5mm do nervo tibial e posterior reparo mediante utilização de câmara de silicone. Internamente à prótese de tubulização do nervo tibial esquerdo em todos os animais, foram inoculadas células-tronco autólogas de medula óssea, coletadas a partir do úmero. Como grupo controle (nervo tibial direito), mediante aplicação da mesma técnica de reparo, solução de NaCl 0,9% foi administrada internamente à prótese. Após 30 dias de observação, os animais foram eutanasiados e foi realizada a avaliação histológica dos segmentos nervosos por meio das colorações de hematoxilina-eosina, luxol fast blue e azul de toluidina. Com os resultados, foi possível concluir que o transplante de células-tronco autólogas associado à técnica de tubulização apresenta vantagens no processo de regeneração nervosa periférica.
Resumo
Background: Colitis murine models have become essential tools to investigate the molecular and cellular mechanisms that lead to inflammatory bowel disease (IBD), such as ulcerative colitis (UC). DSS-induced colitis model faithfully reproduces many of the clinical presentation and immunological disturbances observed in UC. Notwithstanding mice can show differential susceptibilities and responsiveness to dextran sodium sulfate (DSS), and varying DSS concentration and molecular weights appear to be associated with the severity of inflammation. The aim of this study was to analyze the features of mice induced colitis using different DSS concentrations and molecular weights. Materials, Methods and Results: C57BL/6 mice received 2% of high molecular weight DSS (36 000 - 50 000) in drinking water (HDSS2%) or 5% of the same molecular weight (HDSS5%); other group received 5% of low molecular weight DSS (10 000) (LDSS5%). During the 7 days of DSS administration, animals were observed for weight loss, stool consistency and presence of blood feces to determine the disease activity index (DAI). On day 8, colons were removed, measured and weighed for indirect assessment of inflammation. The tissue samples were processed for histological analysis and blood samples were collected for hematological analysis. Our results demonstrated that HDSS5% group began to show significant clinical signs sta
Background: Colitis murine models have become essential tools to investigate the molecular and cellular mechanisms that lead to inflammatory bowel disease (IBD), such as ulcerative colitis (UC). DSS-induced colitis model faithfully reproduces many of the clinical presentation and immunological disturbances observed in UC. Notwithstanding mice can show differential susceptibilities and responsiveness to dextran sodium sulfate (DSS), and varying DSS concentration and molecular weights appear to be associated with the severity of inflammation. The aim of this study was to analyze the features of mice induced colitis using different DSS concentrations and molecular weights. Materials, Methods and Results: C57BL/6 mice received 2% of high molecular weight DSS (36 000 - 50 000) in drinking water (HDSS2%) or 5% of the same molecular weight (HDSS5%); other group received 5% of low molecular weight DSS (10 000) (LDSS5%). During the 7 days of DSS administration, animals were observed for weight loss, stool consistency and presence of blood feces to determine the disease activity index (DAI). On day 8, colons were removed, measured and weighed for indirect assessment of inflammation. The tissue samples were processed for histological analysis and blood samples were collected for hematological analysis. Our results demonstrated that HDSS5% group began to show significant clinical signs sta
Resumo
Background: Biological membranes demonstrate superiority over synthetic ones for its biocompatibility and strength in the reduction of abdominal hernias. Recents tissue engineering researches add mesenchymal stem cells to biological membranes with the purpose of obtaining additional cellular proliferation and consequent muscle regeneration, using biological membranes as cellular scaffolds. This article aimed to study the influence of mesenchymal stem cells in muscle regeneration in abdominal hernias, reduced with biological membranes. Materials, Methods & Results: Adult Wistar rats underwent abdominal hernia-inducing. They were divided into two groups as to the form of treatment for the reduction of hernia: stem cells associated with biological membranes or only biological membranes. After the treatment the macro and microscopic reviews were carried out in days seven, 14 and 60 postoperatively. Preparation of bovine pericardium with glycerin 98% presented efficiency in decellularization and conservation, maintaining its strength and avoiding bacterial growth. The mesenchymal stem cells obtained from bone marrow of adult Wistar rats, had capacity of proliferation. The majority of the cells was positive for the expression of surface antigens CD44, CD29 and CD99 and was negative for CD 34. In the differentiation trials, the same cells were able to differentiate into adipocytes
Vários tipos de implantes, naturais ou sintéticos, vêm sendo testados no reparo cirúrgico de hérnias. As membranas biológicas, ou arcabouços dérmicos descelularizados, apresentam reduzida formação de aderência entre o implante e as vísceras, diminuição da formação de fístulas, infecções e recorrências. Também apresentam resistência suficiente para suportar a pressão abdominal, evitando deiscências e eviscerações. [...]