Tacrolimus Repairs Glomerular Podocytes In Rats With Adriamycin Induced Nephropathy

Objective: To investigate the effects of the novel immunosuppressant tacrolimus on podocyte injury in adriamycin induced nephropathy models and study the repair mechanism.Methods:Estimating the model of minimal change disease(MCD), then interfered with neotype immunosuppressant tacrolimus treatment. The experimental animals were randomly divided into four groups: the control group, the model group, and the tacrolimus treatment group with 0.5 mg/kg·d. The model of MCD was established by twice adriamycin injection( firstly with the dose of 4mg/kg, and secondly with the dose of 3.5mg/kg). The 24-hour urinary protein of rats was obtained from each group before and after modeling in the first, seventh, fourteenth, 21 th, 28 th and 35 th day, and stored in the-80? fridge, together sent to our department of clinical laboratory to check the 24-hour urinary protein. All rats were killed in the last day, and kidneys were collected by different ways according to different purposes. The foot process coalition in podocyte was obtained with electron microscope. TUNEL was implemented in the renal glomerulus, and the WT-1?nephrin?caspase-3 and p38 antigens were tested with immunohistochemistry or immunofluorescence to detect their location and quantity. Checking the expression of caspase-3 and p38 proteins by Western-blot. So as to obtain the injury of podocytes after adriamycin injection, including the ultrastructural changes of podocyte, the apoptosis and number changes in podocyte, and study the mechanism of transdifferentiation from PEC to podocytes. Furtherly obtaining the changes of the indexes above-mentioned after tacrolimus treated.Results: 1. The 24-hour urine protein was markedly increased after adriamycin injection(P<0.05), and the number of podocytes was obviously reduced, the foot process was generally fused, successfully establishing the MCD models of podocyte injury. 2. The 24-hour urine protein was markedly reduced after tacrolimus treatment (P<0.05), and the foot process coalition was improved, the number of podocytes was recovered(P<0.05). 3. The caspase-3 protein was up-regulated in the model group, and then down-regulated after tacrolimus treatment(P<0.05), making the truth that tacrolimus can directly resist podocyte apoptosis. 4. In contrast with the control group, the PEC started to express podocyte specific proteins, such as WT-1, nephrin and signaling molecule p38 in the model group, and the PEC, expressing these proteins, were markedly increased after tacrolimus treatment(P<0.05). 5. The expression of p38 was up-regulated in the model group(P<0.05), and further up-regulated after tacrolimus treatment.Conclusion: Podocyte injury can be treated with tacrolimus by the mechanism of apoptosis inhibition, p38 MAPK signal path activation, and promoting the transdiffrentiation of PEC to podocytes.