Activation of the cannabinoid receptor type 2 by the agonist JWH133 promotes the first wave of in vitro spermatogenesis.

Abstract

Oncological procedures have irreversible side effects on germ cells for childhood cancer survival boys. In vitro culture of prepubertal testicular tissue has been proposed to restore fertility; however, recent data on animal models showed that meiotic and post-meiotic progression was impaired. As potential key inducers of the mitosis-meiosis switch, type 2 cannabinoid receptor (CB2 ) has been proposed to play a central role in the meiotic entry of male germ cells. Herein, the in vitro first spermatogenesis wave in mice was used to understand the impact of CB2 activation on the differentiation of spermatogonia until elongated spermatids. A first set of cultured testicular explants of 6.5days post-partum (dpp) mice was performed to assess the impact of a range of JWH133 supplementation (10nm, 100nm, 1µm, 10µm). Then, the progressive development of germ cells at key timepoints of spermatogenesis was evaluated throughout (i) in vitro culture (day 2 [D2], D3, D6, D10, D18, and D30) coupled with (ii) in vivo counterparts (8.5, 9.5, 12.5, 16.5, 24.5, and 36.5 dpp). CB2 was detected at the plasma membrane of cells, and a successful completion of spermatogenesis was obtained in vitro. One day after the activation of CB2 by 1μm of the agonist JWH133, percentage of zygotene spermatocyte I increased. After 30days of culture, (i) an enrichment of haploid germ cells detected by flow cytometry, (ii) a reduced necrotic area, and (iii) an increase in the density of post-meiotic germ cells were observed. We showed that the activation of CB2 improves in vitro entry into meiosis and differentiation of spermatogonia, mimicking physiological meiotic transition.