Figure 1: (a) Point probe (35 points) for calculation of volumetric density in testis structures (to estimate the volume density of the seminiferous tubules and interstitial tissue). The total number of points located on each structure is counted in each field of view and is compared with the total number of points in the volume measurement formula: Vv = SP structure/SP reference (H and E, ×200). (b) Framework probe, for estimating the length density of seminiferous tubules (H and E, ×200). The probe consists of banned lines (black lines) and counting lines (yellow lines). Tubules are inserted into the frame probe or are contacted by counting lines. Length density formula: Lv = 2(SQ/a (frame) × Sframe), where a is frame area, SQ is sum of the structures counted, and Sframe is the total number of the random counted frames (conventionally, 200 field of view) (H and E, ×200).