Summary
Light and electron microscopic pancreatic changes were studied in 47 metabolically normal and in 59 subdiabetic rabbits that had received a diet containing 1% cholesterol for periods ranging from two weeks to 12 months. Subdiabetes had been induced by small doses of alloxan alone or by appropriate, sequentially administered injections of cortisone and alloxan. Nine animals served as normal controls. In keeping with the low avidity of rabbit pancreatic tissue for cholesterol as demonstrated biochemically by others (Ho and Taylor, 1968, 1971), the observed pancreatic lesions in normal and in subdiabetic, hypercholesterolemic animals were generally much less severe and less extensive than were alterations in other organs, such as the kidneys and parts of the cardiovascular system, of these same rabbits. Membrane-bound vacuolar inclusions harboring granular, membranous and amorphous material and giving the cytoplasm a foamy appearance were noted in the exocrine pancreatic acinar cells, and similar vacuoles as well as occasional cholesterol clefts were present in several endocrine A and B cells. Atheromatous plaques were much rarer in pancreatic blood vessels than in the arterio-arteriolar systems of the kidney and of the heart, and they were nearly always localized and nonocclusive. Comparatively more histologic lesions were noted in rabbits fed cholesterol for longer periods of time. There were no differences in the incidence of pancreatic alterations between metabolically intact and subdiabetic animals. it is concluded that all tissue components of the rabbit pancreas (exocrine and endocrine parenchyma, interstitium, and blood vessels) display a greater resistance towards the development of morphologically demonstrable lesions in hypercholesterolemia than do most other organs of this animal.
Zusammenfassung
Die Bauchspeicheldrüsen von 47 stoffwechselgesunden und 59 latent diabetischen Kaninchen, die 2 Wochen bis 12 Monate lang eine Diät mit 1% igem Cholesterinzusatz erhalten hatten, wurden licht- und elektronenmikroskopisch untersucht. Der latente Diabetes war durch kleine Alloxandosen oder mit Cortison-Alloxan-Gaben induziert worden. Neun unbehandelte Tiere dienten als Kontrolle. In Übereinstimmung mit der von Ho und Taylor (1968, 1971) biochemisch ermittelten niedrigen Affinität des Kaninchenpankreas für Cholesterin waren die morphologisch faßbaren Veränderungen in der Bauchspeicheldrüse bei den hypercholesterinämischen Kaninchen beider Gruppen erheblich weniger ausgeprägt und stärker umschrieben als etwa die in den Nieren und im kardiovaskulären System derselben Tiere. In den schaumig umgewandelten exokrinen Drüsenzellen fanden sich ultrastrukturell von Membranen umschlossene Vacuolen mit körnigen oder lamellären Strukturen oder mit amorpher Substanz. Einige A- und B-Zellen der Langerhansschen Inseln enthielten ähnliche vacuoläre Einschlüsse und gelegentlich auch Cholesterinnadeln. Atheromatöse Veränderungen waren in den Arterien und Arteriolen des Pankreas deutlich seltener als in der Niere oder im Herzen und zudem stärker umschrieben wie auch fast immer nicht-occlusiv. Mit der Fütterungsdauer nahm die Häufigkeit der Läsionen zu, doch zeigten sich keine quantitativ signifikanten Unterschiede zwischen stoffwechselgesunden und latent diabetischen Tieren. Morphologisch gesehen unterliegt also das Pankreas des Kaninchens in allen seinen Anteilen (exokrinen Drüsen, Langerhansschen Inseln, Zwischengewebe und Blutgefässen) dem schädlichen Einfluß einer langdauernden Hypercholesterinämie in erheblich geringerem Maße als das für die meisten anderen Organe dieses Tieres gilt.
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Supported by a grant from the National Institutes of Health (A-2203).
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Wellmann, K.F., Volk, B.W. The pancreas in experimental hypercholesterolemia in normal and in subdiabetic rabbits. Virchows Arch. Abt. A Path. Anat. 353, 99–109 (1971). https://doi.org/10.1007/BF00548970
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DOI: https://doi.org/10.1007/BF00548970