Fig. 6

Main testicular dysfunctions following SARS-CoV-2 infection. a–d Immunostaining showing Caspase-3 positive germ cells (green arrows) in testes of controls and COVID-19 patients (scale bars = 50 μm). a’ Negative control (scale bars = 50 μm). e Heat map of critical genes from the tubular and intertubular compartments. The colors compare COVID-19 patients to controls. Green: lower expression than controls. Red: higher expression than controls. f Measurement of the tunica propria thickness (t-test; two-tailed; infected groups vs control; *p < 0.05). g Leydig cell volume density in testes of controls and COVID-19 patients (t-test; two-tailed; infected groups vs control; *p < 0.05). h Measurement of intratesticular testosterone using RIA (t-test; two-tailed; infected groups vs control; ***p < 0.001; **p < 0.01). i–l Immunostaining for caspase 3, evidencing positive labeling in Leydig cells (green arrows) (scale bars = 50 μm). i’ Negative control (scale bars = 50 μm). m–n TEM showing the presence of several electron-dense vacuoles in Leydig cell cytoplasm (white arrows) (scale bars = m 2 μm; n 1 μm). o–r Trichrome Masson staining in the testis of controls and COVID-19 patients. In higher magnification, inserts (P1, P2, and P3) show the collagen deposition in the seminiferous tubules (scale bars = 200 μm). s–u Quantification of total collagen fibers, type I collagen, and type III collagen (t-test; two-tailed; infected groups vs control; *p < 0.05; COVID-19-P1 vs COVID-19-P2; #p < 0.05). v Quantification of newly formed blood vessels (CD31+) (t-test; two-tailed; infected groups vs control, *p < 0.05). w Quantification of testicular hemorrhage (t-test; two-tailed; infected groups vs control, *p < 0.05). Testicular hemorrhage was classified as normal (x) and as containing high numbers of red blood cells (arrows) in tubular and intertubular compartments (y), a vast number of red blood cells in the intertubular compartment (z), and few red blood cells in the intertubular compartment (α) (scale bars = 50 μm). P1, P2, P3: phases 1, 2, and 3 COVID-19 patients, respectively. BV, blood vessels; IC, intertubular compartment; ST, seminiferous tubule cross-section. Individual values can be found at https://doi.org/10.6084/m9.figshare.16777786.v8