Immunohistochemical (IHC) analysis

For histology, testicular biopsy from those azoospermia men was fixed in 4% paraformaldehyde (PFA) solution (Solarbio, Beijing, China), embedded in paraffin, and cut into 5-μm thick sections. After sectioning, the slides were rehydrated and then processed with hematoxylin and eosin staining. Testicular biopsies from a fertile patient (who underwent percutaneous testicular biopsy for oligozoospermia) and from the patient with the TEX11 mutation underwent IHC staining. A mouse-specific HRP/DAB (ABC) Detection IHC Kit (Abcam, Hong Kong, China) was used for IHC staining. Briefly, after rehydration, sections were blocked with Hydrogen Peroxide Block Reagent (Abcam) for 10 min. The sections were then boiled for 15 min in Sodium Citrate Antigen Retrieval Solution (Solarbio). After cooling to room temperature, the rest of the procedure was conducted according to the IHC Kit product protocol. Immunostaining of TEX11 was carried out using a primary polyclonal goat-anti-human TEX11 antibody (1:100 diluted, Abcam), with secondary mouse-anti-goat IgG-B antibody (1:200 diluted, Santa Cruz Biotechnology, Shanghai, China).