Effect Of GSK3β Inhibitor On CTGF And ICAM-1of Kidney In Type2Diabetc Rats

Diabetic Nephropathy (Diabetic Nephropathy, DN) is a rather severe complication ofdiabetes. The main pathological manifestations of DN are shown in the hypertrophy ofglomeruli, increase of thickness of basement membrane, over accumulation of extracellularmatrix, glomerulosclerosis, tubular atrophy and interstitial fibrosis reference. GlycogenSynthase Kinase-3β（GSK-3β）, which is the key regulatory factor of various kinds ofsignaling pathways, such as Wnt/β-catenin, PI3K/Akt, insulin etc. is related to manydiseases. The GSK-3β inhibitors is an effective inhibitor to treat the type2diabetes byaffecting the functions of insulin, participating in the production and development of theinsulin resistance, and assisting insulin to adjust sugar metabolism and promoteepithelial-to-mesenchymal transition (EMT).Previous researches tended to focus onglomerular lesions, however, there are a limited number of studies on the occurrence anddevelopment of the renal tubulointerstitial lesion and its pathogenesis. Recently, it has beendemonstrated that the severity of the development of tubulointerstitial fibrosis is moreclosely correlated with a progressive decline in renal function, compared to glomerularlesions reference. Therefore, objective evaluation of the significance of inhibiting GSK-3βduring the treatment of DN can provides news ideas and important theoretical foundation forthe future clinical operation that the deterioration of DN is retarded through inhibitingGSK-3β.Objective：This experiment wanted to establish a rat model of GSk3β inhibitor, combined withdiabetic nephropathy. Then, In this study, for DN mice,inhibitors ofGSK-3have beendemonstrated to influence albuminuria、 blood sugar、 Scr、 glomerular pathologicalmechanism and inflammation function in details. And then the renal protective effect ofGSK3β inhibitors on streoptozotocin-induced DN rats is observed and its possiblemechanism is explored.Methodology：Male Wistar rats were randomly divided into four groups: normal control group (NCgroup,n=10), GSK3β inhibitors group (CI group,n=10), diabetes Nephropathy (DN group n=10) and DN treated group with GSK3β inhibitors (DI group,n=15).The rat model of DNwas established by single intraperitoneal injection of STZ (55mg/kg). The model of DNcan be verified to be a success, provided that three consecutive blood glucose measurementsin a row are all higher than16.7mmol/L, and meanwhile the rats are urine protein-positive.If the rat model is successful, the rat model of DN is built by intraperitoneal injection ofGSK3β inhibitors (8mg/ml lithium chloride,15mg/kg every other day for10days on end),while the rats in other groups were injected with the same volume of normal saline. Then,the rats are killed before detection on24-hours urinary protein and collection of the heartblood for serum creatinine (Scr). Renal morphology is kept and then observed by immunefluorescence. The expression of connective tissue growth factor (CTGF) in kidney isdetected by immunohistochemistry. Finally, the serum level of ICAM-1is measured withenzyme-link immunosorbent assay (ELISA).Results:Rat models of DN, DN combined with GSK3β inhibitors nephropathy model areconstructed successfully. NC group with GSK3β inhibitors perform normally. The generalcondition of every disease model group, such as body weight, kidney weight/body weight,urine protein and blood glucose, presents specific features variation.1)Diabetes treatmentgroup with GSK3β inhibitors is significantly better than the diabetes nephritis group interms of general condition and Survival Rate, which is75%and50%respectively. Only onein the fifteen survived cases has kidney tumor change in DI group. The ones is eliminated.2)Each Measurement Indicators of DN and DI group are higher than the NC group (P <0.01),GSK-3β inhibitors could have decreased urine volume、Scr、blood sugar of DN rats, therewere no significantly differences. Compared with those in the DN group, the albuminuria ofDI rats was low contrasted with DN group(P<0.01).3）The renal pathology results in eachmodel show that the normal group rats have neither thickening nor infiltrates.Compared withthose in the NC group, the Body Weight of DN rats have decreased（P<0.01）;and kidneyweight/body weight increased (P <0.01). The PAS indicates that the kidney of DN rats haveenlarged in glomerular area (P <0.01), extracellular matrix has dilated, widened in diffusemesangial area, thickened in part of the visible capillary basement membrane and occludedin capillary cavity. Renal tubular epithelial cells have diffuse granular degeneration and focalvacuolar degeneration, protein casts could be seen in the small tubes；Renal interstitialvisible focal inflammatory cell with mild fibrosis.4）Compared with that of DN group, thekidney weight/body weight does not drop remarkably, while the glomerular proportion decreases （P <0.01）. Kidney-related pathological changes are alleviated. Kidneypathological form of NC group and GSK-3β inhibitors rats group has no insignificantchanges. Compared with NC group, the DN rats show an elevated expression of CTGF inkidney as well as reduced activities of serum ICAM-1levels (all P <0.05). Compared withDN group, GSK3β inhibitors could not weaken the protein expression of CTGF in kidney(P>0.05).But, Serum ICAM-1levels decreased in DI group (all P <0.05).Conclusion:1. GSK-3β inhibitors（Licl）can ameliorate the general condition of the DN rats andraise their survival rate,drug concentration and toxicity are related,whereas, it might result inadverse effect to a certain extent for long-term users.2.GSK-3β inhibitors（Licl）can attenuate DN Glomerulus and tubulointerstitiumpathologic and functional changes. And there is no notable effect for rats in GSK-3βinhibitors group.3. GSK-3β inhibitors（Licl）can not influence renal tubular epithelial cells CTGFexpression and can not distinctly attenuate tubulointerstitium of diabetic nephropathy rats.4. GSK-3β inhibitors（Licl）can lower ICAM-1level in the serum of diabetic rats,which might be related to the inhibition of the NF-κB activation and inflammatory response.