• males show a progressive decline in the average number of litters per mouse and the average number of pups per litter from 8 to 16 weeks of age and become totally infertile at ~32 weeks of age, indicating accelerated infertility with age

• males show no significant differences in the size and weight of testes and epididymides or testis histology at 8, 16 and 32 weeks of age relative to wild-type controls

• male meiosis is normal, as confirmed by a spermatocyte spreading assay

• males show a progressive decline in the average number of litters per mouse and the average number of pups per litter from 8 to 16 weeks of age and become totally infertile at ~32 weeks of age, indicating accelerated infertility with age

• testes show increased signals of ribosome and endoplasmic reticulum-associated proteins, indicating that autophagic removal of excessive cytoplasmic materials is impaired during spermatogenesis

• testes show increased expression of LC3 and p62 and reduced expression of autophagy-associated proteins LAMP2 and GABARAP

• both testicular spermatids and epididymal spermatozoa show aberrant mitochondria with dilated intermembrane spaces

• both testicular spermatids and epididymal spermatozoa show an incomplete fibrous sheath

• number of spermatozoa is progressively reduced in different segments of the epididymis (including the proximal and distal cauda) from 8 to 32 weeks of age

• number of acrosomal granules (AG) is abnormal (missing or multiple) or AGs are ectopic or morphologically abnormal

• TEM analysis showed defects in acrosome development, including missing or abnormal Golgi apparatus and ectopic or abnormal acrosomal granule (AG) number, resulting in an aberrant acrosome structure in the maturation phase

• some round spermatids exhibit an absent or disordered Golgi apparatus

• both testicular spermatids and epididymal spermatozoa show excessive residual cytoplasm, indicating a defect in cytoplasm removal

• sperm are aggregated into bundles or sperm flagella are inseparable

• both testicular spermatids and epididymal spermatozoa show impaired individualization

• number of spermatozoa is progressively reduced in different segments of the epididymis (including the initial segment, caput, distal caput, and proximal and distal cauda) with increasing age

• males become completely infertile at ~32 weeks of age

• in an IVF assay using cumulus-intact oocytes, the zygotic formation rate, 2-cell embryo rate, and blastocyst rate are all significantly lower than in wild-type controls

• reduced fertilization rate is related to impaired cumulus cell dispersal

• however, no significant differences are observed with cumulus-free oocytes

• in a cumulus cell dispersal assay, sperm show an impaired capacity to penetrate the cumulus-oocyte complex (COC)

• cumulus cell dispersal is significantly delayed in the presence of cauda epididymal sperm or sperm protein extracts

• however, the COC dispersal ability of sperm or sperm protein extracts is restored by adding purified human sperm hyaluronidase to the IVF medium

• cauda epididymal spermatozoa show a significant decline in the % of progressive motility

• CASA analysis showed a significant decline in all sperm motility parameters, including curvilinear velocity (VCL), straight-line velocity (VSL), average path velocity (VAP), amplitude of lateral head displacement (ALH), linearity (LIN), wobble (WOB = VAP/VCL), straightness (STR = VSL/VAP), and beat-cross frequency (BCF)

• cauda epididymal spermatozoa are almost immotile by ~32 weeks of age

• SpermQ analysis showed that the lateral swing amplitude of sperm flagella is significantly reduced when the head is fixed by polylysine

• both testicular spermatids and epididymal spermatozoa show aberrant mitochondria with dilated intermembrane spaces

• both testicular spermatids and epididymal spermatozoa show an incomplete fibrous sheath

• number of spermatozoa is progressively reduced in different segments of the epididymis (including the proximal and distal cauda) from 8 to 32 weeks of age

• number of acrosomal granules (AG) is abnormal (missing or multiple) or AGs are ectopic or morphologically abnormal

• TEM analysis showed defects in acrosome development, including missing or abnormal Golgi apparatus and ectopic or abnormal acrosomal granule (AG) number, resulting in an aberrant acrosome structure in the maturation phase

• some round spermatids exhibit an absent or disordered Golgi apparatus

• some round spermatids exhibit an absent or disordered Golgi apparatus

• testes show increased signals of ribosome and endoplasmic reticulum-associated proteins, indicating that autophagic removal of excessive cytoplasmic materials is impaired during spermatogenesis

• testes show increased expression of LC3 and p62 and reduced expression of autophagy-associated proteins LAMP2 and GABARAP

• cauda epididymal spermatozoa show a significant decline in the % of progressive motility

• CASA analysis showed a significant decline in all sperm motility parameters, including curvilinear velocity (VCL), straight-line velocity (VSL), average path velocity (VAP), amplitude of lateral head displacement (ALH), linearity (LIN), wobble (WOB = VAP/VCL), straightness (STR = VSL/VAP), and beat-cross frequency (BCF)

• cauda epididymal spermatozoa are almost immotile by ~32 weeks of age

• SpermQ analysis showed that the lateral swing amplitude of sperm flagella is significantly reduced when the head is fixed by polylysine

• testes show increased signals of ribosome and endoplasmic reticulum-associated proteins, indicating that autophagic removal of excessive cytoplasmic materials is impaired during spermatogenesis

• testes show increased expression of LC3 and p62 and reduced expression of autophagy-associated proteins LAMP2 and GABARAP