Streptozocin-induced Pancreatic Islet Destruction in Beef Cows

Abstract

Abstract. Streptozocin (STZ) induces diabetes mellitus in sheep and pigs. To test the effect of STZ in cattle, cows were given 75-150 mg STZ per kilogram of body weight. Cows receiving 150 mg/kg required euthanasia within 24 hours after infusion because of the severe systemic effects of STZ. Seven cows receiving doses of Յ100 mg/kg had mild to marked decrease in islet immunoreactivity for insulin and in pancreatic islet density and mild to severe tubulointerstitial nephritis. Two cows receiving 75 and 85 mg/kg STZ regained their ability to produce insulin and return blood glucose to basal levels. One cow given 100 mg/kg STZ developed insulin insufficiency consistent with type I diabetes mellitus. These findings demonstrate the susceptibility of the bovine pancreas to STZ; however, severe systemic complications were encountered. Alternative dosages and methodologies should be considered in future attempts to induce diabetes in cattle using STZ.Key words: Cattle; diabetes; experimental disease; immunohistochemistry; insulin; pancreas; streptozocin.Insulin has been implicated in the control of ovarian function in vivo and in vitro in rats, 9 pigs, 13 beef heifers, 5 and humans. 2 Researchers have used an energyrestricted cow model to investigate mechanisms of reduced fertility rates in beef cattle. 1,12,17 In these studies, insulin was reduced in the estrous cycle immediately before nutritionally induced anestrus. However, researchers postulate that both over-and underfed animals may have altered mixed-function oxidase activities in the liver that influence the metabolic clearance rate of reproductive hormones. 21 To offset postulated problems associated with endocrine and metabolic events in nutritionally altered animals, our laboratory designed and implemented studies to develop a chemically induced diabetic cow model conceived as a result of the apparent success observed in manipulating the reproductive events in streptozocin (STZ)-induced diabetic pigs and sheep. 3,13 Streptozocin (2-deoxy-2[[(methyl-nitroamino) carbonyl] amino] ␣ (and ␤)-D-glucopyranose) 14 is a naturally occurring glucosamine-nitrosourea (aminoglycoside) antibiotic derived from the fermentation broth of Streptomyces achromogenes. This compound induces a type I diabetic condition by selectively destroying beta cells within the islets of Langerhans. 23

Evaluation of the Pancreatoprotective Effect of Nannochloropsis oculata Extract against Streptozotocin-Induced Diabetes in Rats

“…In the current study, STZ caused histopathological alterations in the pancreatic tissue. This was in accordance with Higdon et al (2001) who reported that STZ caused inflammatory changes in pancreatic islets of diabetic rats. Consequently, this leads to atrophy in islands of the Langerhans cells associated with vacuolation of islet cells.…”

Ameliorative Anti-Diabetic Activity ofDangnyosoko, a Chinese Herbal Medicine, in Diabetic Rats

“…10,26) As diabetic processes, atrophy and vacuolation of islet cells according to the destruction of B cells were demonstrated in the present study by the decrease in the number of pancreatic islets observed in histomorphometry. The anti-diabetic activities of numerous herbal extracts have been observed based on the histopathology and histomorphometry of the pancreas.…”

Anti-diabetic Activity of SMK001, a Poly Herbal Formula in Streptozotocin Induced Diabetic Rats: Therapeutic Study

“…In the STZ induced diabetic rats, inflammatory changes were detected in the pancreatic islets results from selectively destroy of insulin-producing B cells and consequently, atrophy and decrease of the numbers of pancreatic islets observed are induced. 10,28) As diabetic process, atrophy and vacuolation of islet cells according to destroy of B cells were demonstrated in the present study with decrease of the number of observing pancreatic islets on the histomorphometry. However, these changes are dramatically and dose-dependently inhibited by SMK001 treatment, and antidiabetic activities of numerous herbal extracts have been observed base on these histopathology and histomorphometry of the pancreas.…”