Serial frequent or multiple Tru-cut® testicular biopsies in rams enable assessment of histological characteristics or transcriptional profiles, with no acute or chronic adverse effects

This study aimed to evaluate the feasibility of performing multiple testicular biopsies in rams using Tru-cut® needles, assessing histological structure, gene expression, and potential complications such as effects on semen quality, testicular blood flow, and ultrasonographic echotexture. In Exp. 1, six mature rams underwent testicular biopsies at intervals (0, 3, 6, 12, 24, and 48 h) using a 16 G Tru-cut® needle, with alternating testes for each collection. Benzathine benzylpenicillin and flunixin meglumine were administered for infection and inflammation control. Local anesthesia and post-biopsy care included lidocaine, digital pressure, and ice application. Testicular samples were analyzed for gene expression related to inflammation, oxidative stress, and steroidogenesis. Semen quality was assessed pre-biopsy and 28 days post-biopsy. Ultrasonographic evaluations of the scrotum and testes were conducted before biopsies and on days 5, 9, 13, 17, and 21 post-biopsies. In Exp. 2, a second group of six mature rams underwent biopsies using 14 G needles, with two samples taken from each testis. Samples were histologically examined for structural preservation. Scrotal skin temperature was measured using infrared thermography, and testicular blood flow was assessed via color Doppler ultrasonography, with measurements taken before and on days 1, 2, 4, 6, 8, 10, 25, 50, 75, and 100 post-biopsies. Semen collection followed the same schedule as in Exp. 1. In Exp. 3, biopsies were performed on different testicular regions (upper, middle, lower) using 12 G, 14 G, and 16 G needles to compare structural preservation. Samples were histologically analyzed. No clinical signs of injury, inflammation, or fluid accumulation were observed. Scrotal pain, increased temperature, swelling, and bleeding were absent, and behavioral signs indicative of pain were not detected. Gene expression remained unchanged, and no significant alterations in seminal characteristics or testicular echogenicity were observed. A slight increase in resistivity and pulsatility indices was noted in Exp. 2. Biopsies with 14 G and 16 G needles resulted in structural disruptions, while 12 G needles better preserved testicular parenchyma. Multiple testicular biopsies using Tru-cut® needles did not cause significant morphological changes, alter transcriptional profiles, or affect semen or ultrasonographic characteristics, demonstrating that this method is viable for monitoring acute molecular changes in the testes.