Exploration Of Clinical Effects And Mechanisms Of Shenkang Injection Improving Diabetic Tubulopathy By Targeting Renal Tubular EMT And Endoplasmic Reticulum Stress-induced Apoptosis

[Background/Aims]Shenkang Injection(SKI)is a commonly used Chinese herbals'compound preparation for the clinical treatment of chronic kidney disease(CKD).The clinical practices and the basic researches have shown that SKI is not only suitable for the treatment of chronic renal failure,but also suitable for patients with diabetic kidney disease(DKD)in early and middle stages when it is combined with the protocol of the conventional basic treatments of diabetes,which can not only reduce urinary protein but also improve renal function.However,there is no report on the clinical efficacy of intervening renal tubular injury of DKD by SKI directly.We hypothesized that,for some patients with DKD in early and middle stages with renal tubular injury,the conventional treatments combined with SKI could not only improve renal function,but also reduce renal tubular injury and delay the progression of DKD.Therefore,we conducted a single-center,small sample retrospective study on the clinical efficacy of SKI improving renal tubular injury in patients with DKD.[Methods]The case data from the 40 patients with DKD in G3b stage were collected and analyzed retrospectively.According to the different treatments,the patients were divided evenly into two groups(Group A and Groups B).Group A was control group with 20 cases and Group B was therapeutic group with equally 20 cases as Group A.The treatment in Group A was"conventional basic treatment";The treatment adopted by the B group patients was"conventional basic treatment+SKI".Before the patients received the above treatments,disease duration,gender,age,body mass index(BMI)were collected,and other parameters,which were basic indicators,such as systolic blood pressure(SBP),estimated glomerular filtration rate(eGFR),as well as diastolic blood pressure(DBP),combination of hypertensive disease or not,and antihypertensive drugs(the situation of ACEI/ARB used in hypertensive patients)were compared.Then,traditional Chinese medicine(TCM)syndrome quantitative scores,conventional biochemical indicators,renal tubular injury indicators and safety indicators were compared respectively after receiving the different treatments for 2 weeks.[Results]For patients with DKD in G3b stage,"conventional basic treatment+SKI"improved their TCM syndrome,and other conventional biochemical indicatorssuch as serum creatinine(Scr),estimated glomerular filtration rate(eGFR),serum urea nitrogen(BUN),serum uric acid(UA),renal tubular injury indicator[urinary N-acetyl-?-D-glucosaminidase,(UNAG)]and urine albumin-creatinine ratio(UACR),serum cystatin C(CYS-C))became better;however,there was no effects on serum total carbon dioxide(TCO2),serum nitric oxide(NO),serum retinol binding protein(RBP)as well as the security indexes including alanine aminotransferase(ALT),aspartic transaminase(AST),red blood cell(RBC)and haemoglobin(Hb).[Conclusions]We found that,for the case data collected from the 40 patients with DKD in G3b stage,TCM syndrome quantitative scores,some conventional biochemical indicators and renal tubular injury indicator of some patients can be improved by"conventional basic treatment+SKT".Therein,"conventional basic treatment+ SKI" had better effects for ameliorating the levels of Scr,eGFR,UNAG,UACR,and CYS-C,compared to "conventional basic treatment".[Background/Aims]Previous studies have shown that diabetic tubulopathy(DT)may precede glomerulopathy and microangiopathy,and plays a crucial role in the progression of diabetic kidney disease(DKD)to end-stage renal disease.Shenkang injection(SKI)is a common drug in the clinical treatment of chronic kidney disease(CKD).However,it remains unclear whether SKI can mitigate DT.With the aim of exploring a new therapeutic strategy for DT,we sought to elucidate the effects and mechanisms of SKI attenuating DT based on renal tubular epithelial-mesenchymal transdifferentiation(EMT)and endoplasmic reticulum stress(ERS)-induced apoptosis compared to rosiglitazone(ROS),a commonly used insulin sensitizer in clinic,and then,to reveal molecular targets of SKI protecting against renal tubular epithelial cells injury by targeting the ERS-related PERK-eIF2a-ATF4-CHOP signaling pathway.[Methods]The "unilateral nephrectomy method","high-fat feed feeding method"combined with "intraperitoneal injection of streptozotocin(STZ)" were used to create an animal model to establish a rat model of diabetic nephropathy-tubular disease.The experimental rats were divided into four groups as follows:normal group(fed with 2 mL of double distilled water per day),DKD model group(DKD model without other treatment,fed with 2 mL of double distilled water per day),SKI group(After DKD modeling,they were treated by SKI injection,and 5 g·kg-1 of SKI solution was given by gavage every day)and ROS group(DKD was treated by ROS after modeling,5 mg·kg-1 was given by gavage every day).All of them were raised carefully every day.After 6 weeks of administration,all rats of the four groups were sacrificed.The urine,blood and kidney tissue were collected respectively and various indexes were detected.To observe and analyze the effects of SKI and ROS,the indicators of renal tubular injury,renal tubular EMT,renal tubular epithelial cell apoptosis,and renal tubular ERS were detected.Furthermore,the related PERK-eIF2?-ATF4-CHOP signaling pathway was studied.Besides,NRK-52E cells were adopted for the in vitro experiments research,which was to observe the roles of Shenkang injection and rosiglitazone on the apoptosis indicators,the ERS indicators and the related PERK-eIF2?-ATF4-CHOP signaling pathway activity.[Results]With the DKD-based DT rat model and renal tubular epithelial cellular model,we demonstrated that:?SKI and ROS could improve the general condition,the renal morphology and some routine biochemical parameters as well as the urinary enzymes in the model rats;?SKI and ROS could improve or inhibit the renal tubular injury and EMT;?SKI and ROS could reduce the renal tubular epithelial cell apoptosis and ERS;? SKI and ROS could inhibit the activation of PERK-eIF2?-ATF4-CHOP signaling pathway.[Conclusions]SKI attenuated DT by inhibiting the renal tubular EMT and ERS-induced apoptosis.In addition,the effects of SKI were similar to those of ROS.This finding will contribute to the application of SKI in the clinical treatment of DT.