Avaliação dos efeitos da eliminação da tensão através de ancoramento epineural: estudo experimental comparando resultados eletrofisiológicos e histomorfométricos após diferentes técnicas de reparo no nervo

Epineural stitches are a means to avoid tension in a nerve suture. We evaluate this technique, relative to interposed grafts and simple neurorraphy, in a rat model. METHOD: Twenty rats were allocated to four groups. For Group 1, sectioning of the sciatic nerve was performed, a segment 4 mm long discarded, and epineural suture with distal anchoring stitches were placed resulting in slight tension neurorraphy. For Group 2, a simple neurorraphy was performed. For Group 3, a 4 mm long graft was employed and Group 4 served as control. Ninety days after, reoperation, latency of motor action potentials recording and axonal counts were performed. Inter-group comparison was done by means of ANOVA and the non-parametric Kruskal-Wallis test. RESULTS: The mean motor latency for the simple suture (2.27±0.77 ms) was lower than for the other two surgical groups, but lower than among controls (1.69±0.56 ms). Similar values were founding in both group 1 (2.66±0.71 ms) and group 3 (2.64±0.6 ms). When fibers diameters were compared a significant difference was identified between groups 2 and 3 (p=0.048). CONCLUSION: Good results can be obtained when suturing a nerve employ with epineural anchoring stitches. However, more studies are needed before extrapolating results to human nerve sutures.A aproximação através de pontos epineurais é uma forma de se reduzir a tensão numa neurorrafia. Neste estudo esta técnica é avaliada através da sua comparação com a interposição de enxertos e neurorrafia simples num modelo experimental utilizando o rato. MÉTODO: Vinte ratos foram utilizados e divididos em 4 grupos. No Grupo 1, após a ressecção de 4 mm, os cotos do nervo foram aproximados através de pontos de ancoramento epineurais e suturados com tensão. No Grupo 2, uma neurorrafia simples foi realizada após secção do nervo. No Grupo 3, um enxerto de 4 mm foi utilizado para o reparo e o Grupo 4 foi utilizado como controle. Noventa dias após, os nervos foram novamente expostos e a medida da latência do potencial de ação motor e a contagem axonal foram realizados. A comparação entre os grupos foi realizada através da comparação entre as médias (ANOVA) e com o teste não-paramétrico de Kruskal-Wallis. RESULTADOS: A média da latência motora na sutura simples (2,27±0,77 ms) foi menor em relação aos outros dois grupos onde o nervo foi seccionado e reparado e maior que o grupo controle (1,69±0,56 ms). Resultados semelhantes foram identificados nos grupos 1 (2,66±0,71 ms) e 3 (2,64±0,6 ms). Uma diferença significativa diâmetros das fibras foi identificada quando comparados os grupos 2 e 3 (p=0,048). CONCLUSÃO: Resultados equiparáveis aos obtidos com enxerto podem ser obtidos quando a neurorrafia é realizada com pontos epineurais de ancoramento com tensão, mas estudos adicionais são necessários antes desses resultados serem extrapolados para o reparo de nervo em seres humanos

Afectación de vías de apoptosis cuando se administra inmunosupresión a los donantes: rol de TNFA, BAX y BCL-2

El trasplante renal en ratas isogénicas es el modelo más ampliamente usado para el estudio de factores de daño no-inmunológicos. TNF∝ es una citokina pro inflamatoria que esta up-regulada en el proceso de injuria por isquemi-reperfusión (IRI) y está involucrada en la vía extrínseca de apoptosis. Bcl-2 y Bax son genes anti y pro apoptóticos involucrados en la vía intrínseca. Nuestro objetivo fue determinar cuáles vías apoptóticas están afectadas por la administración de diferentes drogras inmunosupresoras (sirolimus y FK506) al donanteFacultad de Ciencias Médica

Modelo de donante cadavérico con criterio neurológico de muerte en la rata de laboratorio

El modelo experimental de trasplante de órganos y tejidos en la rata, se ha llevado a cabo tradicionalmente con donante vivo. La complejidad de lograr un donante cadavérico en roedores de laboratorio, ha restringido su utilización. Esta situación limita la extrapolación de los resultados a la realidad clínica, donde mayoritariamente se utilizan órganos extraídos de donantes cadavéricos. La necesidad de poseer resultados experimentales, tanto en donante vivo como cadavérico, nos ha llevado a optimizar el modelo de donante de órganos en rata con criterio neurológico de muerte y asistencia respiratoria mecánica.Facultad de Ciencias Médica

Preconditioning donor with a combination of tacrolimus and rapamacyn to decrease ischaemia-reperfusion injury in a rat syngenic kidney transplantation model

Reperfusion injury remains one of the major problems in transplantation. Repair from ischaemic acute renal failure (ARF) involves stimulation of tubular epithelial cell proliferation. The aim of this exploratory study was to evaluate the effects of preconditioning donor animals with rapamycin and tacrolimus to prevent ischaemia–reperfusion (I/R) injury. Twelve hours before nephrectomy, the donor animals received immunosuppressive drugs. The animals were divided into four groups, as follows: group 1 control: no treatment; group 2: rapamycin (2 mg/kg); group 3 FK506 (0, 3 mg/kg); and group 4: FK506 (0, 3 mg/kg) plus rapamycin (2 mg/kg). The left kidney was removed and after 3 h of cold ischaemia, the graft was transplanted. Twenty-four hours after transplant, the kidney was recovered for histological analysis and cytokine expression. Preconditioning treatment with rapamycin or tacrolimus significantly reduced blood urea nitrogen and creatinine compared with control [blood urea nitrogen (BUN): P < 0·001 versus control and creatinine: P < 0·001 versus control]. A further decrease was observed when rapamycin was combined with tacrolimus. Acute tubular necrosis was decreased significantly in donors treated with immunosuppressants compared with the control group (P < 0·001 versus control). Moreover, the number of apoptotic nuclei in the control group was higher compared with the treated groups (P < 0·001 versus control). Surprisingly, only rapamycin preconditioning treatment increased anti-apoptotic Bcl2 levels (P < 0·001). Finally, inflammatory cytokines, such as tumour necrosis factor (TNF)-α and interleukin (IL)-6, showed lower levels in the graft of those animals that had been pretreated with rapamycin or tacrolimus. This exploratory study demonstrates that preconditioning donor animals with rapamycin or tacrolimus improves clinical outcomes and reduce necrosis and apoptosis in kidney I/R injury.Facultad de Ciencias MédicasComisión de Investigaciones Científicas de la provincia de Buenos Aire

Preconditioning donor with a combination of tacrolimus and rapamacyn to decrease ischaemia-reperfusion injury in a rat syngenic kidney transplantation model

Reperfusion injury remains one of the major problems in transplantation. Repair from ischaemic acute renal failure (ARF) involves stimulation of tubular epithelial cell proliferation. The aim of this exploratory study was to evaluate the effects of preconditioning donor animals with rapamycin and tacrolimus to prevent ischaemia–reperfusion (I/R) injury. Twelve hours before nephrectomy, the donor animals received immunosuppressive drugs. The animals were divided into four groups, as follows: group 1 control: no treatment; group 2: rapamycin (2 mg/kg); group 3 FK506 (0, 3 mg/kg); and group 4: FK506 (0, 3 mg/kg) plus rapamycin (2 mg/kg). The left kidney was removed and after 3 h of cold ischaemia, the graft was transplanted. Twenty-four hours after transplant, the kidney was recovered for histological analysis and cytokine expression. Preconditioning treatment with rapamycin or tacrolimus significantly reduced blood urea nitrogen and creatinine compared with control [blood urea nitrogen (BUN): P < 0·001 versus control and creatinine: P < 0·001 versus control]. A further decrease was observed when rapamycin was combined with tacrolimus. Acute tubular necrosis was decreased significantly in donors treated with immunosuppressants compared with the control group (P < 0·001 versus control). Moreover, the number of apoptotic nuclei in the control group was higher compared with the treated groups (P < 0·001 versus control). Surprisingly, only rapamycin preconditioning treatment increased anti-apoptotic Bcl2 levels (P < 0·001). Finally, inflammatory cytokines, such as tumour necrosis factor (TNF)-α and interleukin (IL)-6, showed lower levels in the graft of those animals that had been pretreated with rapamycin or tacrolimus. This exploratory study demonstrates that preconditioning donor animals with rapamycin or tacrolimus improves clinical outcomes and reduce necrosis and apoptosis in kidney I/R injury.Facultad de Ciencias MédicasComisión de Investigaciones Científicas de la provincia de Buenos Aire

Impaired exercise performance and muscle Na(+),K(+)-pump activity in renal transplantation and haemodialysis patients.

We examined whether abnormal skeletal muscle Na+,K+-pumps underlie impaired exercise performance in haemodialysis patients (HDP) and whether these are improved in renal transplant recipients (RTx)