Abstract Introduction: Kidney-transplantation is a life-saving treatment option for patients with chronic renal failure. Preserving the viability of the organ from the removal of the organ until transplantation into the recipient is one of the most essential factors affecting postransplant success. Kidney tissue is exposed to ischemia following removal of the organ from the donor, initiating some cellular events. Amniotic fluid (AF) was previously reported as a preservation solution for the liver, but not for the kidney yet. The aim of this study is to investigate the effectiveness of AF as a preserving solution for rat kidneys compared with the University of Wisconsin (UW) and Histidine-Tryptophan-Ketoglutarate (HTK), which are reported to be the most commonly used and preferred preserving solutions. Methods: Forty male Wistar albino rats were used in this study in four experimental groups. Group 1: Ringer Lactate (RL, Control) group, Group 2: HTK group, Group 3: UW group, and Group 4: AF group. A midline incision was performed, and the renal artery was isolated under ketamine and xylazine anesthesia. Solutions relevant for groups (cooled to + 4°C) were used for kidney perfusion. Nephrectomy was applied, and the removed kidneys were placed into + 4°C standard organ storage solution and stored at + 4° C for 12 hours. After 12 hours of storage, samples from the kidney tissues were fixed in 10% neutral buffered formalin. Histopathological, immunohistochemistry evaluation and apoptosis detection via TUNEL method were performed. Results: The results of the AF group were close to those of the UW and HTK groups. Tubular necrosis and vacuolization were high in the RL solution group when compared to the other experimental groups. Immunohistochemistry staining for all three markers (TNF-alpha, IL-18, and iNOS) was decreased in the amniotic fluid group, similar to the UW and HTK groups. Also, the number of apoptotic cells was decreased in the AF group compared to control. Conclusions: UW, HTK, and AF had similar and higher protective effects compared to the RL solution. Thus, AF may be used as an inexpensive and readily available alternative natural tissue preservation solution.

Resumen Introducción: El trasplante de riñón es una opción de tratamiento que puede salvar la vida de pacientes con insuficiencia renal crónica. Preservar la viabilidad del órgano desde su extracción hasta el momento del trasplante en el receptor es uno de los factores principales que influyen en el éxito postrasplante. El tejido renal está expuesto a la isquemia después de la extracción del órgano del donante, lo cual da inicio a algunos eventos celulares. Existen estudios que indican que el líquido amniótico (LA) funciona como una solución de conservación para el hígado, pero aún se desconoce si sucede lo mismo con el riñón. El objetivo de este estudio es investigar la efectividad del LA como solución conservadora para los riñones de ratas, en comparación con la solución de Wisconsin (UW) y la solución de histidina-triptófano-cetoglutarato (HTK), que son los conservantes más utilizados y preferidos. Material y métodos: Se emplearon cuarenta ratas albinas macho de la cepa Wistar en este estudio, en cuatro grupos experimentales. Grupo 1: grupo solución de lactato sódico compuesta (LSC, Control); Grupo 2: grupo HTK; Grupo 3: grupo UW y Grupo 4: grupo LA. Habiendo aplicado anestesia con ketamina y xilazina, se realizó una incisión en la línea media y se aisló la arteria renal. Se utilizaron soluciones relevantes para grupos (enfriadas a + 4° C) para perfusión renal. Se realizó una nefrectomía, y los riñones extraídos fueron colocaron en una solución estándar de almacenamiento de órganos a + 4° C y se conservaron así durante 12 horas. Después de dicho periodo de almacenamiento, las muestras de los tejidos renales se fijaron en formalina tamponada neutra al 10%. Se llevaron a cabo una evaluación histopatológica e inmunohistoquímica y una detección de apoptosis mediante el método TUNEL. Resultados: Los resultados del grupo LA fueron cercanos a los de los grupos UW y HTK. La necrosis tubular y la vacuolización fueron más altas en el grupo de la solución LSC que en los otros grupos experimentales. La tinción inmunohistoquímica para los tres marcadores (TNF-alfa, IL-18 e iNOS) disminuyó en el grupo de líquido amniótico, similar a los grupos UW y HTK. Además, el número de células apoptóticas menguó en el grupo LA, en comparación con el de control. Conclusiones: UW, HTK y LA tuvieron efectos protectores similares y superiores en comparación con la solución LSC. Por lo tanto, el LA puede usarse como una solución alternativa de bajo costo para la preservación de tejidos naturales.

Abstract Purpose: To evaluate the effect of amniotic fluid in liver preservation in organ transplantation, and compare it with standard preservation solutions. Methods: The groups consisted of Group 1: Ringer Lactate (RL) group, Group 2: HTK group, Group 3: UW group, Group 4: AF group. The livers of rats from Group 1, 2, 3, and 4 were perfused and placed into falcon tubes containing RL, HTK, UW, and AF solutions at +4°C, respectively. The tubes were stored for 12 hours in the refrigerator at +4°C. Tissue samples were taken at the 6th and 12th hours for histopathological examinations of the perfused livers, and storage solutions for biochemical analyzes at 6th and 12th hours. Results: AF was shown to maintain organ viability by reducing the number of cells undergoing apoptosis. Histopathological changes such as sinusoidal dilatation, hydropic degeneration, and focal necrosis were found to be similar to the groups in which the standard organ preservation solutions were used. Additionally, the results of INOS, IL-10, and TNF-α,which were evaluated immunohistochemically, have been shown to be similar to the UW and HTK groups. Conclusions: AF provided conservation similar to UW and HTK in the 12-hour liver SCS process. The fact that apoptosis values are comparable to standard preservation solutions supports the success of AF in the cold storage of the liver.