Comparison of Intestinal Warm Ischemic Injury in PACAP Knockout and Wild-Type Mice

Abstract

Pituitary adenylate cyclase-activating polypeptide (PACAP) is present in the gastrointestinal tract and plays a central role in the intestinal physiology, mainly in the secretion and motility. The aim of our study was to compare the ischemic injury in wild-type and PACAP-38 knockout mice following warm mesenteric small bowel ischemia. Warm ischemia groups were designed with occlusion of superior mesenteric artery for 1, 3, and 6 h in wild-type (n = 10 in each group) and PACAP-38 knockout (n=10 in each group) mice. Small bowel biopsies were collected after laparotomy (control) and at the end of the ischemia periods. To determine oxidative stress parameters, malondialdehyde (MDA), reduced glutathione (GSH), and superoxide dismutase (SOD) were measured. Tissue damage was analyzed by qualitative and quantitative methods on hematoxylin/eosin-stained sections. In PACAP-38 knockout animals, tissue MDA increased significantly after 3 and 6 h ischemia (133.97 ± 6,2; 141.86 ± 5,8) compared to sham-operated (100.92±3,6) and compared to wild-type results (112.8±2,1; 118.4±1.03 μmol/g, p< 0.05). Meanwhile, tissue concentration of GSH and activity of SOD decreased significantly in knockout mice compared to wild-type form (GSH, 795.97±10.4; 665.1±8,8 vs. 893.23±μmol/g; SOD, 94.4±1.4; 81.2±3.9 vs. 208.09± 3,7 IU/g). Qualitative and quantitative histological results showed destruction of the mucous, submucous layers, and crypts in knockout mice compared to wild-type tissues. These processes correlated with the warm ischemia periods. Our present results propose an important protective effect of endogenous PACAP-38 against intestinal warm ischemia, which provides basis for further investigation to elucidate the mechanism of this protective effect.

The effects of pituitary adenylate cyclase activating polypeptide in renal ischemia/reperfusion

“…there are similar findings in peripheral tissues in ischemic lesions. A greater damage could be observed in PACAP deficient mice in case of intestinal ischemia while intact small intestine of deficient mice was similar to that of wild-type mice [9,10]. We have also reported such findings in case of the kidneys of PACAP deficient mice [46].…”

Protective Intestinal Effects of Pituitary Adenylate Cyclase Activating Polypeptide

“…Quantitative histological analysis confi rmed these observations: both mucosal and submucosal thickness as well as crypt depth were more severely decreased in mice lacking endogenous PACAP. Studying the oxidative stress markers, results similar to those observed in cold ischemic injury were obtained: levels of MDA were more significantly increased in the KO groups, while those of the antioxidant SOD and GSH were more severely decreased than in the wild type animals ( [ 57 ], Fig. 17.1 ).…”

“…We also performed warm ischemic injury in PACAP KO mice [ 57 ]. Warm ischemia was induced by occlusion of the superior mesenteric artery for 1, 3 or 6 h. Similarly to the above studies, histological and biochemical analyses were performed.…”

A PACAP-38 citoprotektív és antiinflammatórikus hatásának vizsgálata vékonybél-autotranszplantációs modellben

“…[10][11] A PACAP-38 antiapoptotikus, antiinflammatórikus és antioxidáns protektív hatása számos in vitro és in vivo kí-sérletben igazolódott. [12][13][14][15] Pontosan még nincs tisztázva, hogy milyen mechanizmusokon keresztül hat, de az igen, hogy a bélszöveti I/R-s károsodás a béltraktusban citokinfelszabadulást eredményez. 16 Számos gyulladásos modellben leírták, hogy a PACAP antiinflammatórikus hatása részben a citokinek és kemokinek termelődésének gátlása révén érvényesül.…”

“…Korábbi meleg I/R-s vékonybélmodell-ben végzett kutatásaink hasonló eredményeket mutattak az endogén PACAP-38 szintjének változása tekintetében. 12 A hideg ischaemiát követő PACAP-38-szint csökkenését okozhatja mind az ischaemiás sejtek fokozott PACAP-38-felvétele, mind a PACAP-38 szintézisének csökkenése, mind pedig a sejtkárosodás miatti fokozott PACAP-lebomlás. Hasonló megfigyelést tettek kísérletes fekélymodell-ben is, ahol a PACAP immunreaktivitásának acut csökke-nését figyelték meg.…”