Determination of urinary N-acetyl-ß-D glucosaminidase levels in experimental blunt renal trauma in rats

In this study, we evaluated applicability of urinary N-acetyl-beta-D-glucosoaminidase (NAG) levels for diagnosis and follow-up in blunt kidney injury.Twenty young-adult Sprague-Dawley rats were divided into two groups consisting of 10 rats in each. In sham group, left kidney exploration with midline abdominal insicion was made under general anesthesia. In trauma group, after left kidney exploration, 20 gr weighted masses were fall down through specially prepared 30 cm pipe on kidneys. Isolated renal injury was observed macroscopically. After interventions, rats were followed-up in metabolic cages. Before and after the interventions, urine was collected for analysis with strip, determination of levels of urinary NAG, and creatinin (Cr) at 0-6th, 12-24th, 24-36th and 36-48th postoperative hours in both groups. Before intervention, control groups were not formed, because determined values were compared with basic values. At the end of 48 hours, rats in both groups were sacrificed with high dose anesthetic agents and then their kidneys were removed for histopathological examination. Data were analysed using Mann-Whitney U and Kruskal Wallis tests.Macroscopic examinations on traumatized kidneys revealed grade II injury in 4 rats, grade III injury in 6 rats, and histopatological examinations showed relevant changes related to trauma. No pathological finding was observed in sham group. After the intervention, macroscopic hematuria was observed in all traumatised rats. No hematuria was seen in sham group. After the intervention, urinary NAG/Cr levels in trauma group were found to be significantly higher than their basic levels (2,659±0,840) at 0-6th hour, 12-24th, 24-36th and 36-48th hours (113,00±45,109; 14,703±13,962; 10,027±10,362; 8,253±7,294). In sham group, only the level of urinary NAG/Cr levels at 0-6th hour (69,366±51,618) was significantly higher than basic levels (3,213±1,392). When these two groups were compared, the increase in levels of NAG/Cr at 0-6th hour in trauma group was significantly higher.After isolated blunt renal trauma, urinary NAG levels increase at early stage. However, more detailed clinical studies are needed to develop NAG levels as a criteria in the follow-up of blunt renal trauma.Key words: Renal injury, trauma, NAG, experimental study