Ultrastructural and mitochondrial defects in sperm from infertile men with DNAH3 variants.
(A) TEM analysis of sperm obtained from a normal control and patients harboring DNAH3 variants. Cross-sections of the midpiece, principal piece and endpiece of sperm from normal control showed the typical ‘‘9 + 2’’ microtubule structure, and an IDA and an ODA were displayed on the A-tube of each microtubule doublet. Cross-sections of the midpiece, principal piece and endpiece of sperm from the patients displayed absent or disordered CPs, MTDs and ODFs, as well as an evident missing of the IDAs in different pieces of the flagella. M, mitochondria sheath; ODF, outer dense fiber; MTD, microtubule doublets; CP, central pair; IDA, inner dynein arms; ODA, outer dynein arms. Scale bars, 200 nm. (B) Immunofluorescence staining of TOM20 in sperm from the patients and normal control. Red, TOM20; green, α-Tubulin; blue, DAPI; scale bars, 5 μm.