Introduction. Literature data and our own research indicate that therapy with immature cell secretion products (secretome) has a pronounced nephroprotective effect both in acute kidney injury and in chronic renal failure (CRF). Considering that the source of the complex of signaling molecules stimulating reparative processes in organs are low-differentiated cells of functionally and anatomically immature organs in a state of deveopment, the question arises to what extent tissue transplantation of these organs reproduces the effect of therapy with a secretome of stem cells in relation to the progression of CRF.

Material and methods. The experiments were carried out on 40 outbred male rats weighing 260-290 g, in which CRF was modeled by resection of 4/5 functionally active renal parenchyma. In the 1st series (control), no therapeutic actions were performed. In the 2nd series, after modeling CRF, a course of therapy with Cellex, the active component of which is the secretome of pig embryonic brain cells, was carried out in the form of 2 10-day courses with a 10-day break between them. In the 3rd and 4th series, immediately after CRF modeling, kidney or testicle tissue obtained from newborn baby rats (1-2 days after birth) was injected under the capsule of the resected kidney as a source of immature cells. Tissues of different organs were used to assess the severity of the tissue-specific effect of therapy.

Results. 7 days after the modeling of CRF in all series, a deterioration of more than 2 times of all functional parameters was revealed. After 1 month, in the control and in the 2nd and 3rd series, a tendency to an increase in GFR was revealed, which did not reach statistical significance, whereas in the 4th series, the increase in GFR turned out to be statistically significant. After 2 months in the control series, there was a repeated decrease in the GFR index, whereas in all experimental series, GFR continued to increase or remained at subnormal values. The activity of tubular reabsorption of sodium and calcium after a significant decrease after 7 days to 1 month in the control series increased slightly (but unreliably), and after 2 months they again decreased to values 2 times lower than normal. In all experimental series, after 1 and 2 months, the reabsorption of these electrolytes was at values close to normal. The improvement was especially pronounced in groups 2 and 4. After 7 days, the activity of intracellular enzymes (aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH)) in the blood increased in all series with a gradual decrease in hyperfermentemia after 2 months, more pronounced in group 4, as well as in all experimental groups with respect to LDH. Histological examination of the condition of neonatal transplants revealed the destruction of transplanted kidney tissue and a viable testicular graft. Conclusion. Transplantation of neonatal organ tissue under a kidney capsule to rats with CRF has a comparable nephroprotective effect with therapy with the secretome of embryonic cells (Cellex drug). A more pronounced improvement in functional parameters during testicular tissue transplantation is explained by the preservation of the viability of the graft.