Assessment of cell reserve in the ipsilateral and contralateral kidney after partial / total nephrectomy

In this study, In order to understand the adaptation mechanism of the kidney after partial / total nephrectomy performed at different rates, The effect of age factor on reserve and proliferation was evaluated experimentally to determine whether the stem cell reserve increased in the renal compensatory mechanism and whether there was a difference in the effect of nephrectomy on reserve and proliferation. In our study, 2 main groups were formed, including 3 week old pups and 8 week old rats. Each group had its own control and experiment group. Control groups were divided into 3 groups in their age group and 10 male rats were used in each control group. Experimental group was divided into 9 groups in their age group and 6 male rats were used in each group. The rats underwent single-sided total nephrectomy, 1/3 nephrectomy and 5/6 nephrectomy, and post-operative 15, 30 and 60 day evaluations were performed. The weights of the rats were measured at the beginning and end of the experiment. Biochemical and immunohistochemical evaluations of blood and kidney samples were made before the end of the experiment. BUN and creatinine measurements were done as biochemical parameters and statistically compared. In the tissue samples, the stem cell reserve was evaluated by immunofluorescence double staining (CD90 and CD105), and the proliferation was visualized by immunohistochemical Ki67 staining. In our study, weights of rats in the control group did not show any significant change with respect to both age and nephrectomy types. The preoperative and postoperative weight measurements of the experimental group were significantly lower than the weight increase controls (p <0.05). Weights on day 60 of both 3-week and 8-week rats with 5/6 nephrectomy were significantly lower than 1/3 and unilateral total nephrectomy (p <0.05). BUN values after partial/total nephrectomy increased in all nephrectomy groups compared to control groups, but this increase was not found significant in only 1/3 nephrectomized rats. The increase in BUN in the 5/6 nephrectomy group was more prominent on the 15th postoperative day than in the other groups. Creatinine values of the experimental groups were not significantly different in all postoperative periods, regardless of the age of the rats and nephrectomy techniques, when compared to the control groups (p> 0.05). Given both age groups and all post-operative periods, we found that the most stem cell reserve was in 8-week-old rats with 5/6 nephrectomy. In our study, the highest proliferative activity was detected in unilateral total nephrectomy and 5/6 nephrectomy groups. This increase was observed in glomeruli and interstitial cells, reaching the highest level on day 60, in tubules at postoperative 15th day. Proliferative activity was found to be higher in the 3-week-old rats than in the age-matched rats. This experimental study supports that the kidneys may respond to tissue / volume loss regeneratively through its own stem cell reserve. This response has potential for prevention and treatment of kidney-related and clinical conditions leading to tissue / volume loss. However, these findings need further experimental and clinical investigations.