Characterization of embryonic stem-like cells derived from mouse spermatogonial stem cells following low-intensity ultrasound treatment

Spermatogonial stem cells (SSCs) are able to form embryonic stem-like cells (ES-like cells) and embryonic bodies (EBs). Low-intensity ultrasound stimulation (LIUS) has positive effects on the growth and differentiation of the different cells. In this study, we tried to investigate the effects of LIUS on SSC differentiation to ES-like cells.

SSCs were isolated from neonatal mice and their identification was confirmed by tracking of PLZF, Oct-4, and C-Kit proteins. The SSCs and Sertoli cells were co-cultured in DMEM/F12 supplemented with 15% FBS and LIF. SSCs stimulated by LIUS with 200mW/CM² intensity. Characterization of obtained ES-like cells was confirmed with Sox2, Oct-4, and SSEA-1 immunofluorescence staining. Also, real-time PCR was performed to analyse the expression of c-Myc and Nanog genes in ES-Like Cells and Stra8, Piwil2 and Plzf genes in SSCs after 21 days of the in vitro culture.

Our results showed c-Kit, PLZF and Oct-4 proteins were expressed positively in SSCs and Sox2, Oct-4, SSEA-1 in the ES-like cells by immunocytochemistry. The results of flow cytometry showed a significant increase in expression of c-Myc and Nanog in ES-like cells compared to SSCs (p<.05), whereas the Stra8, Piwil2, and Plzf became down-regulated during 21 days of culture. ES-like markers cell SSEA-1, Sox2 and Oct-4 were increased in the LIUS group compared to the control group (p<.05).

The results indicated that ES-like cells with pluripotency characteristics were derived from SSCs.