Application of rat cryptorchidism model for the evaluation of mesenchymal stromal cell secretome regenerative potential.

Male infertility represents a severe social and medical challenge. In recent years the progress in regenerative medicine promoted the development of novel options to overcome this medical condition. We are elaborating a promising approach to restore spermatogenesis using mesenchymal stromal cell (MSC) secretome components as a novel class of cell-free cell therapy medicinal products for regenerative medicine. However, the choice of the representative in vivo model of spermatogenesis failure to evaluate the effectiveness of regenerative drugs remains challenging. Using the rat model of bilateral abdominal cryptorchidism, we studied the contribution of MSC conditioned medium contained bioactive cell secreted products to the spermatogenesis recovery. The feasibility of this model to evaluate the drug-driven regenerative effects on spermatogenesis restoration after the injury was demonstrated. We revealed significant correlations between the extent of spermatogonial stem cell niche recovery, spermatozoa count and serum concentration of androgens as an indicator of Leydig cell function. The obtained results can be applied in preclinical studies to choose the proper criteria to appraise the specific activity of novel regenerative drugs developed for the treatment of non-obstructive spermatogenesis disorders.