Experimentelle xenogene Immunakreatitis: 1. Histologische Befunde am exokrinen Pankreas der Maus nach Behandlung mit Antimäusepankreas-Kaninchenserum

Abstract

Question: In the pathogenesis of some forms of chronic pancreatitis an immunological influence has been discussed. Therefore, experimental studies of the exocrine pancreas after immunological damage should be done. In this communication histological findings on the mouse exocrine pancreas are presented after treatment with anti-mouse pancreas rabbit serum. Material and methods: a total of 71 adult male white mice was divided into 4 groups treated in the following way: 1. 35 animals with anti-mouse pancreas rabbit serum 2. 1.4 animals with normal rabbit serum 3. 16 animals with physiological saline 4. 6 animals remained untreated. The sera under study and the saline were, without exception, administered intraperitoneally with single doses of 0.3 ml once, resp. twice daily for 0 up to 16 days. Constantly, 3 hours before sacrifice, the animals received the last injection. For histological examination, the fresh pancreas was fixed in formaline. After embedding in paraffin, sections were stained by the following methods: hematoxyline-eosin, trichrome according to Goldner, Giemsa staining, PAS-reaction, and tryptophane demonstration according to Adams (1957). Results: After the first injection treatment with anti-mouse pancreas rabbit serum causes a considerable edema and a mild eosinophilic infiltration, of the pancreatic interstitium. Multiple acinar cell necroses are observed at days 2, 3 and 5. An increasing lymphoplasmacellular and histiocytic interstitial inflammation, invading the parenchyma, is the main finding at later stages of the study. After 16 days of treatment with anti-mouse pancreas immune serum, a diffuse chronic sclerosing pancreatitis develops. Pathogenetically, the multiple pancreatic acinar cell necroses are regarded as the morphologic expression of a cytotoxic immune aggression due to treatment with specific anti-mouse pancreas serum. Acinar cell necroses are only very sporadically found in the control animals treated with normal rabbit serum. The severe chronic histiocytic and lymphoplasmacellular inflammation after immune serum treatment can be explained by 2 processes: on the one hand, it is regarded as a resorptive reaction due to the multiple acinar necroses; on the other hand, it is interpreted as the substrate of an immunologic reaction of the delayed type and/or the serum sickness type due to the repeated injection of foreign proteins with the serum of another species. Therefore, the delayed inflammatory reaction is observed (to a lesser degree) also in the control animals treated with normal rabbit serum without specific antibodies against mouse pancreas. Intraperitoneal injections of physiological saline only inconstantly result in mild, practically insignificant findings in the pancreas.