Fig. 4

Effect of vitrification on histology, DNA integrity and transcriptomics in testicular tissues from adult and juvenile domestic cats. A Representation of morphological damage in vitrified testicular tissue sections showing mature tubule with lumen (upper picture) and immature tubule without lumen (lower picture). Black arrowhead: separation of the basal membrane; white arrowhead: nuclear condensation; black arrows: shrinkage from the basal membrane; asterisk: tubular cell disorganization. Scale bar: 20 μm. B Changes in percentage of morphologically normal seminiferous tubules after vitrification and/or 24 h culture. C Representation of DNA fragmentation in testicular tissue sections. White arrowhead: intact DNA (Hoechst); white arrow: fragmented DNA (TUNEL). Scale bar: 20 μm. D Changes in percentage of DNA fragmentation after vitrification and/or 24 h culture. E Heatmap of one-way hierarchical clustering analysis (Euclidean method, complete linkage) using Z-score for RLE normalized values of genes differentially expressed in vitrified vs. fresh samples, independent of age effect (likelihood ratio test, condition effect, adjusted p-value < 0.05). Sample IDs represent age (A, adult; J, juvenile), tissue condition (F, fresh; V, vitrified) and animal (1 to 10). F Enrichment map displaying enriched gene-sets based on genes responding to vitrification (p-value < 0.05, absolute fold change > 1.5) in vitrified vs. fresh samples from adult and juvenile cats. G STRING network of predicted protein interactions for genes responding to vitrification (p-value < 0.05, absolute fold change > 1.5) in vitrified vs. fresh samples from adult and juvenile cats. Protein interaction clusters were analyzed for functional enrichment within STRING app; clusters with no enrichment were removed from visualization. Additional file 7 contains the web session of both Enrichment map and STRING networks for interactive view