Immunological tolerance to pig-serum partially inhibits the formation of septal fibrosis of the liver in Capillaria hepatica-infected rats

Systhematized septal fibrosis of the liver can be induced in rats either by repeated intraperitoneal injections of pig-serum or by Capillaria hepatica infection. The relationship between these two etiological factors, as far as hepatic fibrosis is concerned, is not known, and present investigation attempts to investigate it. C. hepatica-induced septal fibrosis of the liver was considerably inhibited in rats previously rendered tolerant to pig-serum. Pig-serum-tolerant rats developed antibodies against pig-serum when infected with C. hepatica, but this did not happen when the infection occurred in normal rats. On the other hand, anti-C. hepatica antibodies failed to recognize any epitope in pig-serum, by Western blot. However, no evidence of an immunological cross reactivity was found, at least at the humoral level. Alternatively, cell-mediated mechanisms may be involved, and further investigations are warranted.

Immunological tolerance to pig-serum partially inhibits the formation of septal fibrosis of the liver in Capillaria hepatica-infected rats.

Systhematized septal fibrosis of the liver can be induced in rats either by repeated intraperitoneal injections of pig-serum or by Capillaria hepatica infection. The relationship between these two etiological factors, as far as hepatic fibrosis is concerned, is not known, and present investigation attempts to investigate it. C. hepatica-induced septal fibrosis of the liver was considerably inhibited in rats previously rendered tolerant to pig-serum. Pig-serum-tolerant rats developed antibodies against pig-serum when infected with C. hepatica, but this did not happen when the infection occurred in normal rats. On the other hand, anti-C. hepatica antibodies failed to recognize any epitope in pig-serum, by Western blot. However, no evidence of an immunological cross reactivity was found, at least at the humoral level. Alternatively, cell-mediated mechanisms may be involved, and further investigations are warranted.

Production of septal fibrosis of the liver by means of foreign protein injections into rats.

Similarities and differences in antigenic humoral responses and electrophoretic patterns between Capillaria hepatica and pig-serum were investigated as a contribution to the understanding of hepatic fibrosis induced by the parenteral administration of foreign proteins. Only two out of 10 rats receiving repeated intraperitoneal injections of an extract of Capillaria hepatica-infected mouse liver presented septal hepatic fibrosis (20%). Under the same experimental conditions, 4 out of 9 rats (44.4%) developed septal fibrosis following whole pig-serum administration. Injections of normal mouse liver extracts did not result in hepatic fibrosis. Since a 100% septal fibrosis rate is observed in experimentally Capillaria hepatica-infected rats, it appeared that Capillaria hepatica products continuously released from inside the liver creates a much more effective fibrosis inducing mechanism than the parenteral administration of such factors. Thus, repeated peritoneal administration of a foreign protein to rats would not reveal the full fibrogenic potential it may have under natural conditions.

Production of septal fibrosis of the liver by means of foreign protein injections into rats

Similarities and differences in antigenic humoral responses and electrophoretic patterns between Capillaria hepatica and pig-serum were investigated as a contribution to the understanding of hepatic fibrosis induced by the parenteral administration of foreign proteins. Only two out of 10 rats receiving repeated intraperitoneal injections of an extract of Capillaria hepatica-infected mouse liver presented septal hepatic fibrosis (20 percent). Under the same experimental conditions, 4 out of 9 rats (44.4 percent) developed septal fibrosis following whole pig-serum administration. Injections of normal mouse liver extracts did not result in hepatic fibrosis. Since a 100 percent septal fibrosis rate is observed in experimentally Capillaria hepatica-infected rats, it appeared that Capillaria hepatica products continuously released from inside the liver creates a much more effective fibrosis inducing mechanism than the parenteral administration of such factors. Thus, repeated peritoneal administration of a foreign protein to rats would not reveal the full fibrogenic potential it may have under natural conditions

Hepatic pathology in Capillaria hepatica infected mice

A fibrose septal do fígado se desenvolve regularmente em ratos infectados pela Capillaria hepatica. Com o fito de se verificar se tal tipo de fibrose também se desenvolve em camundongos, 20 animais foram infectados com 100 ou 300 ovos embrionados e examinados histologicamente em vários períodos de tempo, entre 30 até 110 dias após inoculaçäo. Os resultados demonstraram que os camundongos desenvolvem inicialmente uma intensa hepatite aguda, difusa e focal, mas logo estas lesöes säo moduladas, desaparecendo a hepatite reacional difusa e persistindo as lesöes em torno de ovos e restos de vermes. Alguns poucos vermes sobreviveram por todo o período experimental. Embora a fibrose perisinusoidal tenha aparecido em torno das lesöes fibróticas focais, a fibrose septal näo foi observada. Näo se sabe por que a fibrose septal se forma no rato infectado por C. hepatica, mas näo no camundongo, mas o assunto merece investigaçäo, pois importantes aspectos da fibrogênese hepática poderiam estar implicados. Os camundongos parecem melhor adaptados à C. hepatica que os ratos; nos primeiros, a infecçäo é nitidamente autolimitada