Action of tacrolimus on Wistar rat kidneys implanted with Walker 256 carcinosarcoma / Estudo da ação do tacrolimus em rins de ratos Wistar implantados com carcinossarcoma de Walker

PURPOSE: To evaluate the development of Walker 256 tumor in male Wistar rats treated with tacrolimus using an experimental kidney tumor model. METHODS: 40 male Wistar rats were divided into four groups: Tumor group (TU) (n=10), Tacrolimus-Tumor group (TT) (n=10), Tacrolimus group (TC) (n=10) and Control group (C) (n=10). Treatment with tacrolimus was performed in groups TT and TC. Under anesthesia, the right kidney of each animal of TU and TT was accessed through a supraumbilical incision and inoculated with a 0.1mL solution containing 2x10(6) tumor cells (Walker 256 carcinosarcoma tumor cells). Group TC was treated with a saline solution. All the animals of groups TC and TT were treated with tacrolimus (5mg/kg/day) by gavage for 15 days. TU group animals received saline by gavage for 15 days. On the 15th postoperative day, all animals were submitted to euthanasia and blood sampling for analysis of serum creatinine (Cr) and blood urea nitrogen (BUN). Abdominal gross examination was performed, the right kidney removed and prepared for histological analysis by hematoxylin-eosin staining. The resulting data were submitted to statistical analysis by ANOVA. RESULTS: Statistical significance was found when comparing creatinine level between groups TU, TT and TC -TT group culminated with a marked increased in creatinine levels (Cr=1.013 ± 0.3028 mg/mL), TU group (Cr=0.5670 ± 0.03536 mg/dL) P=0.00256, TC group (Cr =0.711 ± 0.1653 mg/mL) P= 0.02832. Statistical significance was found when comparing BUN levels in TT group (71.32 ± 17.14 mg/mL), compared with TU group (45.83 ± 5.046 mg/dL), P=0.000318. There were no statistically significant differences between groups TT and TC (61.23 ± 9.503 mg/mL) P=0.7242. Histological analysis showed a poor evolution in TT group with multiple foci of hemorrhage and cortical invasion by the Walker tumor. CONCLUSION: The Tacrolimus-treated group developed a more aggressive tumor and a drug-related nephrotoxic effect.(AU)

OBJETIVO: Avaliar as alterações na evolução do carcinosarcoma 256 de Walker, inoculado no rim de ratos Wistar, sob tratamento imunossupressor com o tacrolimus. MÉTODOS: Foram utilizados 40 ratos Wistar, machos divididos em quatro grupos de 10: grupo Tumor (TU), Tumor-Tacrolimus (TT), Tacrolimus (TC) e Controle (C). Os ratos dos grupos TU e TT foram inoculados com 0,1 mL de solução contendo 2x10(6) células do tumor de Walker no parênquima do rim direito. Os dos grupos TC e TT receberam tratamento com tacrolimus na dose de 5mg/kg de peso, via gavagem orogástrica durante 15 dias. Os ratos do grupo TU receberam solução salina isotônica pH 7,2. Ao 15º dia de evolução, todos foram submetidos à eutanásia. Amostras de sangue eram coletadas para dosagem de creatinina (Cr) e uréia (Ur) e posteriormente realizada nefrectomia para avaliação histológica. RESULTADOS: As dosagens séricas de creatinina foram maiores no grupo TT (Cr = 1,013±0,3028 mg/mL), que diferiu significantemente dos grupos TU (Cr=0,5670 ± 0,03536 mg/dL) com p=0,00256 e do TC (Cr=0,711 ± 0,1653 mg/mL) com p=0,02832. As dosagens séricas de uréia foram maiores no grupo TT (71,32 ± 17,14 mg/mL), que diferiu significantemente do grupo TU (45,83 ± 5,046mg/dL) com p=0,000318, mas comparado ao grupo TC (61,23 ± 9,503 mg/mL) não houve diferença significante (p=0,7242). No inventário da cavidade abdominal dos grupos TU e TT, observou-se presença macroscópica de tumor em todos os rins direitos; não foram evidenciadas efusões ascíticas, formação de bridas ou metástases tumorais em outros órgãos ou tecidos adjacentes aos rins direitos. CONCLUSÃO: O tacrolimus exerceu efeito nefrotóxico e induziu exacerbação do crescimento do tumor de Walker 256, quando implantado no rim de ratos Wistar.(AU)

Differential recruitment of tetratricorpeptide repeat domain immunophilins to the mineralocorticoid receptor influences both heat-shock protein 90-dependent retrotransport and hormone-dependent transcriptional activity.

The mineralocorticoid receptor (MR) forms oligomers with the heat-shock protein 90 (Hsp90) -based heterocomplex, which contains tetratricopeptide repeat (TPR) domain immunophilins (IMMs). Here we investigated the unknown biological role of IMMs in the MR.Hsp90 complex. Upon hormone binding, FKBP52 was greatly recruited to MR.Hsp90 complexes along with dynein motors, whereas FKBP51 was dissociated. Importantly, the Hsp90 inhibitor geldanamycin impaired the retrograde transport of MR, suggesting that the Hsp90.IMM.dynein molecular machinery is required for MR movement. To elucidate the mechanism of action of MR, the synthetic ligand 11,19-oxidoprogesterone was used as a tool. This steroid showed equivalent agonistic potency to natural agonists and was able to potentiate their mineralocorticoid action. Importantly, aldosterone binding recruited greater amounts of FKBP52 and dynein than 11,19-oxidoprogesterone binding to MR. Interestingly, 11,19-oxidoprogesterone binding also favored the selective recruitment of the IMM-like Ser/Thr phosphatase PP5. Each hormone/MR complex yielded different proteolytic peptide patterns, suggesting that MR acquires different conformations upon steroid binding. Also, hormone/MR complexes showed different nuclear translocation rates and subnuclear redistribution. All these observations may be related to the selective swapping of associated factors. We conclude that (a) the Hsp90.FKBP52.dyenin complex may be responsible for the retrotransport of MR; (b) a differential recruitment of TPR proteins such as FKBP51, FKBP52, and PP5 takes place during the early steps of hormone-dependent activation of the receptor; (c) importantly, this swapping of TPR proteins depends on the nature of the ligand; and (d) inasmuch as FKBP51 also showed an inhibitory effect on MR-dependent transcription, it should be dissociated from the MR.Hsp90 complex to positively regulate the mineralocorticoid effect.