Adipose tissue-derived exosomes restored spermatogenesis in a chemically induced azoospermia rat model: A Histological Study

Background: The most challenging form of infertility, non-obstructive azoospermia (NOA), impacts an estimated 10–20% of males. Testicular sperm extraction with intracytoplasmic sperm injection is the sole method by which NOA males can conceive; however, its success rates are low. Therefore, in this study, we investigated the regenerative potential of adipose tissue-derived exosomes (AT-Exos) in NOA rats by using a calcium chloride (CaCl₂)-induced azoospermia model, considering the possible restorative properties of adipose tissue and its powerful component, exosomes. Methods: Fifty male albino rats were assigned at random into five groups: a control group, an azoospermia group (CaCl₂), a single-dose exosomes group (CaCl₂ + 40 µg exosomes on the 3rd day), a double-dose exosomes group (CaCl₂ + 40 µg exosomes on the 3rd and 17th days), and a recovery group. Following a two-month period, the restoration of spermatogenesis was assessed using histological staining, spermiogram evaluation, and hormonal analysis. Results: The histopathological analysis of testicular tissues treated with exosomes indicated that rats with azoospermia restored their capacity to produce sperm. The Masson’s trichrome stain revealed that the concentrations of the collagen fibers were comparable to those in the control group. Moreover, the spermatogenesis process has been enhanced following single and double doses of exosome transplantation, as demonstrated by immunohistochemistry labeling of proliferating cell nuclear antigen (PCNA) and electron microscopic analysis. Conclusions: Whether given in a single or double dose, exosomes from adipose tissue were effective in treating a rat model of non-obstructive azoospermia. Furthermore, they possess anti-inflammatory properties. Future research should discover the exosome components that provide these benefits.