الفهرس 
Acute kidney injuryOnly 14 pages are availabe for public view
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Abstract
Kidney has many important functions and its main function is to filter and excrete waste products from the blood .Acute kidney injury is a critical health issue which affect the kidney functions and can cause rapid deterioration of kidney and retention of nitrogenous waste products over a period of hours or days and also associated with structural damage. AKI must be handled in a proper treatment way to avoid permanent damage of renal tissues and progression to mortality. There are many reasons can cause AKI such as hypovolemia, atherosclerosis, severe bleeding and sepsis.
Septic-AKI is more severe than non-septic AKI with different underlying mechanisms. With many causes for septic AKI, infection with Gram negative bacteria is still the leading main cause of this serious case. Lipopolysaccharides , is mainly the virulent part of the Gram negative- bacteria outer membrane and it was found that LPS is main cause of sepsis- induced acute renal injury. So, the need to use effective treatment for AKI is increasing.
Toll-like receptors (TLRs) are group of receptors with many roles in innate immune system, TLR4 is one of this group and LPS is its main ligand. When LPS binds and activates TLR4 and so inflammatory cascade through production of cytokines such as TNFα, IL-1β and IL-6 leading to inflammation and damage of surrounding tissue.
Celastrol a natural compound extracted from the root extracts of Tripterygium Wilfodii and used in traditional medicine for many pharmacological effects as anti-inflammatory. Previous studies showed its efficacy in many cases as inhibiting necroptosis and alleviates ulcerative colitis, it has a neuroprotective effect on the treatment of Parkinson’ disease, and it decreases pathogenesis of rheumatoid arthritis. Recent study revealed its ability to block the binding of
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LPS to the TLR4/MD2 complex in mouse primary macrophages and so inhibiting the pathway. The present study was designed to study the effect of Celastrol as a treatment in LPS-induced AKI mice model as well as the possible underlying mechanisms.
The present study was divided into three parts:
Part A: For screening the LPS dose needed to induce Acute Kidney Injury (AKI) in mice
Mice were divided into 4 groups (n=8). Control group received vehicle and LPS was given at three different doses (2.5, 5, 7.5 mg/kg i.p) in the other three groups.
Parameters assessed were:
1-Histopathological examination for kidney tissues: by Hematoxylin & Eosin.
2-Kidney functions markers: Blood urea nitrogen and serum creatinine.
Part B: For selecting the most effective dose of Celastrol that can be used as a treatment. Mice were divided into 6 groups (n=8). Control group received vehicles while LPS group received 2.5mg/kg LPS. Celastrol-treated groups received LPS dose 2.5mg/;g then after 1 hour received Celastrol at dose (2,4,and 6 mg/kg)respectively. The last group received LPS at same dose followed by dexamethasone 2.5mg/kg after one hour.
Parameters assessed were:
1-Histopathological examination for kidney tissues: by Hematoxylin & Eosin.
2-Kidney functions markers: Blood urea nitrogen and serum creatinine.
Part C: for studying the underlying mechanisms by which Celastrol could act as a treatment, mice were divided into five groups. Control group received vehicles, LPS group received 2.5mg/kg, Celastrol-treated group received LPS then after 1 hour
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4mg/kg of Celastrol, Dexamethasone group received LPS then after 1 hour 2.5mg/kg of dexamethasone and last group Celastrol only group received single injection of 4mg/kg Celastrol.
Parameters assessed were:
1- Histopathological examination for kidney tissues: by Hematoxylin & Eosin.
2- Oxidative stress markers: GSH and MDA.
3- Inflammatory markers: TNF-α .IL-6, Nuclear factor kappa B (NF-κB).
4- Apoptotic markers: Caspase-3
5- Markers Related to mechanism: TLR4 expression by RT-PCR.
The results of the present study can be summarized as follows:
1- Screening the LPS dose needed to induce acute kidney injury in mice:
Results showed that injection of mice with LPS dose 7.5mg/kg has high mortality rate on mice so that dose was neglected for further assessment. group of mice kept as control has no histopathological alteration While group of experimentally induced mice by 2.5mg: showed Focal hemorrhage, higher dose 5 mg/kg revealed congestion in the blood vessels associated with perivascular edema. Both doses elevated the BUN and serum creatinine levels in a dramatic way but there was no significant difference between the two doses so the lower dose 2.5mg/kg was selected.
2- Screening the most effective dose of Celastrol needed to alleviates Acute Kidney Injury (AKI) in mice:
Results showed that Celastrol could be used as a treatment for LPS-induced renal injury in dose of 4mg/kg. That dose was sufficient to decrease kidney damage and that was clear in histopathological examination. Also it restored the BUN and serum creatinine levels to normality in a significant way. Celastrol dose 2.5mg/kg
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was not effective while highest dose 6mg/kg has no significant difference in efficacy in relation to dose 4mg/kg. So, Celastrol dose 4mg/kg was selected for mechanistic study.
3. Studying the Mechanism of Celastrol action in treatment of AKI in mice:
Results showed that Celastrol could act as a treatment for LPS-induced renal injury as histopathological examination revealed that Celastrol reversed the histopathological changes showed in LPS group. Celastrol had ability to decrease inflammatory response as it significantly reduced inflammatory markers levels as TNF-α .IL-6, nuclear factor kappa B (NF-κB). Celastrol improved the oxidative stress profile as it decreased GSH and MDA levels. Celastrol also attenuated TLR-4 expression in renal tissues so inflammatory cascade was inhibited as well as attenuated LPS-induced Caspase-3 expression.
Conclusion:
The present study suggests that Celastrol has treatment effects against LPS- induced renal injury and it might be a promising drug for AKI