الفهرس 
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Abstract
Ischemia reperfusion injury of kidney is a common failure factor for organ transplantation and cardiac surgeries. Tissue damage is caused by the ischemic insult and further damage also occurs after reperfusion (Price and Hodeify, 2012). The definite underlying mechanism of ischemia reperfusion injury, (IRI) in kidney is not established yet. However, differentf factors are blamed: accumulation of reactive oxygen and nitrogen species with excess formation of nitric oxide (NO) through increased levels of inducible nitric oxide synthase (iNOS) as well as the involvement of the immune reactions (Malek and Nematbakhsh, 2015).
The exact mechanism of cell death in IRI is not totally clarified yet. Necrosis and apoptosis are two forms of cell death that are well recognized and play roles in cell death after IRI. However, increasing studies have described a genetically programmed and regulated form of necrosis, termed necroptosis. Necroptosis can be triggered by the ligands of the death receptor family and extracellular and intracellular stimuli that induce their expression (Berger et al, 2014).
Necroptosis itself contributes to mediate the subsequent inflammatory reactions developed in IRI in renal tissues. This occurs mainly through the damage associated molecular pattern (DAMP) that is released as a result of necroptosis and activates innate immunity and pro-inflammatory cytokines. This interplay between necroptosis and immune reactions is termed necro-inflammation and these deleterious inflammatory reactions are not exclusively affect the organ suffered from ischemia reperfusion but, it also has a remote effect on other organ that’s called remot organ injury. (Wang et al, 2016).
Necrostatin-1 (Nec-1), a small molecule inhibitor, originally identified by Degterev et al in 2005 was found to selectively target the kinase activity of receptor interacting protein kinase-1 (RIPK-1), a key mediator of necroptosis. Beside its role in necroptosis, necrostatin-1 also thought to have a role in elimination of inflammation.
This study aimed at evaluating the efficacy of Nec-1 administration in the renal functions of IRI rat model, evaluating the inflammation/oxidation mediators when the drug is administered at different time durations of renal IRI. The study was carried out in the physiology department, faculty of medicine, Beni-suif University. Forty-eight male healthy albino rats, approximately 12 weeks of age, and of nearly similar weights ranging from 160 to 200 grams, were included in the study. The rats were randomly divided into the following six main groups.
● group 1(sham): (n=8):
Rats were included in this group and underwent sham operation. Animals belonging to this group were kept under the same experimental conditions as the rest of the groups during the entire study period.
● group 2 (IRI):(n=8):
Rats that were included in this group underwent ischemia reperfusion surgery without any protocol of Nec-1 treatment but injected with an equivalent amount of normal saline.
● group 3:( ttt-befor-IRI) (n=8):
Rats that were included in this group received 1.65mg Nec-1/kg body weight treatment 20min before ischemia induction, then underwent ischemia reperfusion induction.
● group 4:(IRI-ttt-R) (n=8):
Rats that were included in this group underwent ischemia reperfusion induction then received 1.65mg Nec-1/kg immediately at reperfusion.
● group 5:(IRI-ttt-after) group (n=8):
Rats that were included in this group underwent ischemia reperfusion induction then received 1.65mg Nec-1/kg 20min after surgery.
● group 6:(ttt-IRI-ttt) (n=8):
Rats that were included in this group underwent ischemia reperfusion induction then received 1.65mg Nec-1/kg 20min before ischemia induction and another same dose of 1.65mg Nec-1/kg immediately at reperfusion.
Twenty-four hours after ischemia surgery the animals of all groups were euthenticated blood samples and renal tissues were harvested for patho-chemical analysis.
Immune-chemical investigation revealed that there was significant increase in both inflammatory and necroptotic markers in all groups compared with sham. Also these markers was significantly less in the group six, received dual treatment with Nec-1 compared with other treated groups.
Pathological examination of renal tissue with Scoring of renal injury in different renal tissue types in all studied groups, show that signs of damage were most severe in untreated group while the dual treated group showed least damage.
Thease result coming with other studies that ensure the protective role of Nec-1 on the outcome of ischemia reperfusion injury by blocking different pathways ends up with inflammation or necroptosis. Necrostatin-1 exerts renal protective effects through targeting and inhibiting RIPK1 which is considered the initiator of the necroptosis process. Combating necroptosis resulted in significant amelioration of the inflammation/oxidation-induced cellular damage, indicating a link between necroptosis and these injury mediators. Nec-1 treatment in two doses; 20 min before ischemia and at the reperfusion onset resulted in a prominent improvement in the renal functions accompanied with amelioration of the renal tissue inflammation, oxidation and cell injury. The results were confirmed by the renal tissues examination using Hematoxylin and eosin as well as PAS and Bromophenol stains. In addition, treatment with Necrostatin-1 significantly decrease necroptosis and inflammation markers in comparison with the untreated group with the best result in grop received dual treatment (20 minutes befor ischmia and the time of reperfusion). The data suggest a potential clinical utility for necrostatin-1 to reduce renal IRI and improve the post-transplant graft survival.