Expression And Mechanism Of TIM-3 In Drug-induced Acute Kidney Injury

Acute kidney injury(AKI)is a clinical syndrome caused by rapid decline of renal function in a short period of time caused by various causes,manifested by a decrease in glomerular filtration rate(GFR),accompanied by nitrogen products Creatinine,urea nitrogen and other retention,water,electrolytes and acid-base balance disorder,severe cases with multiple system complications.There are many causes of AKI.According to the anatomical location of the cause,it can be divided into three categories:prerenal,renal and retrorenal.Renal AKI refers to the occurrence of renal parenchymal damage,and acute tubular necrosis(ATN)caused by renal ischemia and nephrotoxic drugs or toxins is most common.Cis-platinum(CDS)is an inorganic platinum chemotherapeutic agent,which is widely used in the treatment of various solid malignant tumors.The use of cisplatin can cause various major side effects,such as bone marrow suppression,peripheral neuropathy,ototoxicity,allergic reactions and nephrotoxicity.After a single treatment dose of cisplatin(50-100 mg/m2),approximately 33%of patients will develop nephrotoxicity.The pathophysiology of cisplatin-induced AKI mainly involves 4 main mechanisms:proximal renal tubular injury,oxidative stress,inflammation and renal vascular injury.Proximal renal tubular injury involves several different mechanisms,including apoptosis,autophagy,direct toxicity to renal tubular epithelial cells,DNA damage,and mitochondrial dysfunction.Autophagy is a process of massive degradation of damaged organelles,protein aggregates and other large molecules in the cytoplasm.The basic function is to recover damaged or degenerated cell components,or to maintain homeostasis and cell vitality during nutritional deficiencies.Studies have shown that autophagy has a protective effect on cisplatin-induced proximal renal tubular cell damage.Studies have also pointed out that autophagy has a protective effect on AKI by reducing DNA damage and mitochondrial damage in mice with specific autophagy defects in proximal tubules.T cell immunoglobulin domain and mucin domain-3(Tim-3)is a negative immune-related regulatory molecule originally found on Th1 cells.It is used in many inflammation-related diseases such as Play an important role in tumors and chronic infectious diseases.Recent studies have found that Tim-3 is expressed in various immune cells such as NK cells,dendritic cells and macrophages and plays different regulatory roles.So far,Tim-3 has been less studied in non-neoplastic kidney disease.Studies have found that in ischemia-reperfusion(IRI)-induced AKI,Tim-3 can activate the NLRC4 inflammatory body by activating the TLR4/NF-κB signaling pathway,resulting in aggravated IRI.Other studies have shown that Tim-3 aggravates podocyte damage in diabetic nephropathy by promoting macrophage activation through the NF-κB/TNF-α pathway.Cisplatin-induced AKI is a common clinical drug-induced AKI,which accounts for a considerable proportion of the side effects of various tumor treatment processes.It has not been reported whether Tim-3 participated in the development of drug-induced AKI.This subject uses cisplatin-induced AKI mice as a disease model to explore the role of Tim-3 in drug-induced AKI and its effect on autophagy-related functions.By studying the expression of Tim-3 in AKI and the autophagy-related molecules Changes,clarify that Tim-3 may be involved in the occurrence and development of AKI,and provide new directions and strategies for the research and treatment of pharmaceutical AKI.The main findings are as follows:1.Cisplatin-induced AKI leads to proximal renal tubular injury and increased Tim-3 expressionCisplatin was dissolved in physiological saline at a concentration of 1 mg/ml,and C57BL male mice aged 6-8 weeks were injected intraperitoneally at a dose of 20 mg/kg.After 72 hours,the mice were sacrificed,and blood was collected to measure creatinine and kidney tissue for Western blotting and histological staining.The results showed that the mouse creatinine increased,the body weight decreased,and there were statistical differences,indicating that the AKI mouse model was successfully modeled.The results of HE staining and PAS staining showed that the proximal tubules of the kidneys in AKI mice were damaged,and the tubule epithelial cells were necrotic and shed,the brush border was missing,and the casts were formed and blocked.Tim-3 Western blot results and immunohistochemistry results showed that Tim-3 expression in AKI mice increased and the results were statistically different.2.Blocking Tim-3 aggravates kidney damageCisplatin was used to construct mouse models of AKI group and RMT group.Tim-3 antibody RMT3-23 was intraperitoneally injected into the RMT group 24 hours before and 48 hours after intraperitoneal injection of cisplatin in mice to achieve the effect of blocking Tim-3.After 72 hours,the mice were sacrificed,and blood and kidney tissues were collected for experiments.First,the blocking result of Tim-3 was detected.Western blot and immunohistochemical results of the RMT group showed that the expression of Tim-3 decreased and had statistical differences,indicating that Tim-3 was successfully blocked.The creatinine and the weight of both mouse models increased,indicating that AKI modeling was successful,but there was no statistical difference.Staining of mouse kidney tissue sections showed that the proximal renal tubules of both groups of mice were damaged and necrotic,but the damage of kidney tissue in both groups was scored.Statistical differences.The results of the kidney injury marker molecule NGAL showed that the expression of RMT group was increased and had statistical difference compared with AKI group.These results indicate that blocking Tim-3 is effective,and that blocking Tim-3 aggravates the cisplatin-induced AKI.3.Autophagy is suppressed after blocking Tim-3Previous studies have shown that autophagy has a protective effect on the proximal tubules of the kidney.In order to detect the possible involvement of autophagy,we measured the expression of autophagy molecular markers P62 and LC3II.The results showed that compared with the AKI group,the expression of P62 increased and the expression of LC3II decreased in the RMT group.Since LC3II is an important molecule in the process of autophagosome formation,and P62 has an extremely important regulatory role in the process of autophagy,the changes of these two molecules indicate that after blocking Tim-3,the formation of autophagosomes is suppressed Autophagy is inhibited,which exacerbates kidney damage.In summary,we found that Tim-3 expression is increased in AKI;kidney cortical damage is increased after blocking Tim-3;autophagy is suppressed after blocking Tim-3,indicating that Tim-3 may be involved in the regulation of autophagy function.This subject found that Tim-3 expression increased in drug-induced AKI.After Tim-3 was blocked,autophagy function was inhibited and renal cortical damage was aggravated.This provides a new direction for the research of drug-induced AKI and provides a theoretical basis for finding the clinical therapeutic target of AKI.