Abstract Early puberty is associated with improved long-term reproductive performance. Predicting who will achieve early puberty is limited to intensive, invasive serial blood collections for measurement of reproductive hormones. The vaginal genome during pubertal development has potential as biomarkers of early estrus in the pre-pubertal period. Pre-pubertal gilts (n =13) were followed from d74 ± 3 of age until first estrus or d214 ± 1 of age. Blood, vaginal epithelia, and anogenital distance were collected at five timepoints during reproductive development (d74, d104, d130, d160 and first estrus or end of trial). Total RNA was isolated from vaginal epithelia and relative gene expression of two toll-like receptors (TLR-4 and TLR-5), tacykinin precursor-3 (TAC-3), insulin-like growth factor-1 (IGF-1), and estrogen receptor (ERα)-alpha was quantified by real time RT-PCR, relative to expression of RPLP0. Four gilts exhibited estrus early (< d184), 3 were average (d194 to 195), 3 were late (d203 to 213), and 3 were deemed anestrus. Comparison of expression of each gene relative to d70 was performed using the PCR package in RStudio (version 1.2.5025) and Fisher’s exact t-test for TLR-4, TLR-5 and TAC-3, and ANOVA for ER-alpha and IGF-1. Correlation analysis examined the relationship between anogenital distance and age at first estrus. A single blood draw for serum progesterone was obtained 8 days after recorded first estrus or end of trial; the presence of serum progesterone supports the visual identification of standing estrus. Expression of IGF-1 and TAC-3 were up-regulated 9- and 7-fold, respectively at d160 (P < 0.05). Expression of ERα tended to be upregulated 3-fold at d104 (P = 0.08) and expression of TLR-4 and TLR-5 was not detected until first estrus. Anogenital distance was positively correlated to the first estrus. These transcripts associated with reproduction warrant further investigation into use as biomarkers to detect early estrus. longterm long term performance intensive hormones prepubertal pre period Prepubertal Pre n =13 13 d d7 d21 Blood d74, (d74 d130 d16 trial. trial . trial) tolllike toll like TLR4 TLR 4 (TLR- TLR5, TLR5 5 , TLR-5) precursor3 precursor precursor- TAC3, TAC3 TAC (TAC-3) insulinlike insulin factor1 factor factor- IGF1, IGF1 IGF (IGF-1) ERαalpha alpha RTPCR, RTPCR RT PCR, RT-PCR RPLP0 RPLP ( d184, d184 d184) d194 (d19 195, 195 195) d203 (d20 213, 213 213) anestrus version 1.2.5025 125025 2 5025 Fishers Fisher s ttest t test TLR4, 4, TLR- 3, ERalpha ER IGF1. 1. IGF- TAC- up regulated 9 7fold, 7fold fold 7 fold, 7-fold P 0.05. 005 0.05 0 05 0.05) 3fold d10 0.08 008 08 =1 d2 (d7 d13 d1 (TLR (TAC-3 (IGF-1 d18 d19 (d1 19 d20 (d2 21 1.2.502 12502 502 00 0.0 (d (TAC- (IGF- 1.2.50 1250 50 0. (TAC (IGF 1.2.5 125 1.2. 12 1.2

Abstract The number of antral follicles is considered an important fertility trait because animals with a high follicle count (HFC) produce more oocytes and embryos per cycle. Identification of these animals by genetic markers such as single nucleotide polymorphisms (SNPs) can accelerate selection of future generations. The aim of this study was to perform a genome wide association study (GWAS) on Nelore and Angus heifers with HFC and low (LFC) antral follicle counts. The groups HFC and LFC for genotyping were formed based on the average of total follicles (≥ 3 mm) counted in each breed consistently ± standard deviation. A total of 72 Nelore heifers (32 HFC and 40 LFC) and 48 Angus heifers (21 HFC and 27 LFC) were selected and the DNA was extracted from blood and hair bulb. Genotyping was done using the Illumina Bovine HD 770K BeadChip. The GWAS analysis showed 181 and 201 SNPs with genotype/phenotype association (P ≤ 0.01) in Nelore and Angus heifers, respectively. Functional enrichment analysis was performed on candidate genes that were associated with SNPs. A total of 97 genes were associated to the 181 SNPs in the Nelore heifers and the functional analysis identified genes (ROBO1 and SLIT3) in the ROBO-SLIT pathway that can be involved in the control of germ cell migration in the ovary as it is involved in lutheal cell migration and fetal ovary development. In the Angus heifers, 57 genes were associated with the 201 SNPs, highlighting Fribilin 1 (FBN1) gene, involved in regulation of growth factors directly involved in follicle activation and development. In summary, GWAS for Nelore and Angus heifers showed SNPs associated with higher follicle count phenotype. Furthermore, these findings offer valuable insights for the further investigation of potential mechanism involved in follicle formation and development, important for breeding programs for both breeds. (HFC cycle (SNPs generations (GWAS (LFC counts ≥ ( mm deviation 7 32 (3 4 21 (2 2 bulb K BeadChip 18 20 genotypephenotype genotype phenotype P 0.01 001 0 01 respectively 9 ROBO1 ROBO (ROBO SLIT3 SLIT ROBOSLIT development 5 FBN1 FBN (FBN1 gene summary Furthermore breeds 0.0 00 (FBN 0.

Abstract In the current study, we aimed to assess the expression levels of two circulating microRNAs (miRNA) (oar-miR-485-5p and oar-miR-493-5p) in the ovine plasma during the peri-implantation. After mating, we collected the plasma samples from a total of 8 ewes on day 22 of pregnancy (P22; n = 4) and day 22 of the estrous cycle (C22; n=4). We used mature miRNA sequences for oar-miR-485-5p and oar-miR-493-5p out of one hundred fifty, which were retrieved from our microarray results of previous study. We showed that the miRNA expression of oar-miR-485-5p and oar-miR-493-5p were upregulated in P22 (P<0.05) when compared to C22. Those two miRNAs targeted 311 target genes in the peri-implantation period of pregnancy. Furthermore, we revealed 151 GO/pathway terms in biological process (BP) and 25 GO/pathway terms in molecular function (MF), while we demonstrated 13 GO/pathway terms in cellular component (CC). We revealed three hub genes as interleukin 2 (IL2), interleukin 18 (IL18), and C-X-C Motif Chemokine Ligand 10 (CXCL10). In conclusion, both miR-485-5p and oar-miR-493-5p have the potential to be a biomarker to understand peri-implantation of the ovine pregnancy in the aspect of pregnancy-reflected changes in maternal plasma. study (miRNA oarmiR4855p oarmiRp oar miR 485 5p p oarmiR4935p 493 periimplantation. periimplantation peri implantation. implantation mating P (P22 4 C22 C (C22 n=4. n4 n=4 . n=4) fifty P2 P<0.05 P005 0 05 (P<0.05 31 Furthermore 15 GOpathway GO pathway BP (BP MF, MF , (MF) 1 CC. CC (CC) IL2, IL2 IL (IL2) IL18, IL18 (IL18) CXC X CXCL10. CXCL10 CXCL (CXCL10) conclusion miR4855p miRp pregnancyreflected reflected oarmiR 48 49 (P2 C2 (C2 n= P<0.0 P00 (P<0.0 3 (MF (CC (IL2 IL1 (IL18 CXCL1 (CXCL10 (P (C P<0. P0 (P<0. (IL (IL1 (CXCL1 P<0 (P<0 (CXCL P< (P<

Abstract Cryoprotectants are required to reduce damage caused to the cells due to low temperatures during the cryopreservation. Antifreeze proteins (AFP) have a well-known role in cell membrane protection, while resveratrol is a potent antioxidant. This study assessed the effect of the association of resveratrol concentrations and AFP I in a ram semen extender. Pooled semen of four rams was allocated into six treatments in a factorial arrangement: (CONT, only the semen extender); only AFP I (ANT: 0.1 µg/mL of AFP I), only resveratrol, one treatment with two levels (10 µM/mL or 50 µM/mL of resveratrol); and two treatments with the interactions, with one AFP I and one of the two levels of resveratrol (0.1 µg/mL of AFP I with 10 µM/mL resveratrol; 0.1 µg/mL of AFP I with 50 µM/mL resveratrol). No interaction between factors was observed on sperm kinetics, plasma membrane integrity, hypo-osmotic test, and mitochondrial activity parameters. There was a high probability (P = 0.06) of reducing sperm cells with functional membrane percentage in the hypo-osmotic test and increasing the percentage of sperm with high mitochondrial activity (P = 0.07) was observed in AFP presence. An interaction of AFP and resveratrol was observed in non-capacitated sperm (P = 0.009), acrosomal reaction (P = 0.034), and sperm binding (P = 0.04). In conclusion, the association of resveratrol and AFP did not improve the quality of frozen-thawed semen and even promoted deleterious effects compared to their single addition in the semen extender. The supplementation of 50 µM/mL of resveratrol improved the outcomes of frozen-thawed ram sperm, being a potential cryoprotectant. cryopreservation (AFP wellknown well known protection antioxidant extender arrangement CONT, CONT (CONT extender) ANT (ANT 01 0 1 0. µgmL µg mL I, , I) (1 µMmL µM 5 resveratrol) interactions (0. resveratrol. . kinetics integrity hypoosmotic hypo osmotic parameters P 0.06 006 06 0.07 007 07 presence noncapacitated non capacitated 0.009, 0009 0.009 009 0.009) 0.034, 0034 0.034 034 0.034) 0.04. 004 0.04 04 0.04) conclusion frozenthawed frozen thawed cryoprotectant ( (0 0.0 00 000 0.00 003 0.03 03

Abstract In reproductive technologies, uncovering the molecular aspects of oocyte and embryo competence under different conditions is crucial for refining protocols and enhancing efficiency. RNA-seq generates high-throughput data and provides transcriptomes that can undergo additional computational analyses. This study presented the transcriptomic profiles of in vitro matured oocytes and blastocysts produced in vitro from buffalo crossbred (Bubalus bubalis), coupled with gene co-expression and module preservation analysis. Cumulus Oophorus Complexes, obtained from slaughterhouse-derived ovaries, were subjected to in vitro maturation to yield metaphase II oocytes (616) or followed in vitro fertilization and culture to yield blastocysts for sequencing (526). Oocyte maturation (72%, ±3.34 sd) and embryo development (21.3%, ±4.18 sd) rates were obtained from three in vitro embryo production routines following standard protocols. Sequencing of 410 metaphase II oocytes and 70 hatched blastocysts (grade 1 and 2) identified a total of 13,976 genes, with 62% being ubiquitously expressed (8,649). Among them, the differentially expressed genes (4,153) and the strongly variable genes with the higher expression (fold-change above 11) were highlighted in oocytes (BMP15, UCHL1, WEE1, NLRPs, KPNA7, ZP2, and ZP4) and blastocysts (APOA1, KRT18, ANXA2, S100A14, SLC34A2, PRSS8 and ANXA2) as representative indicators of molecular quality. Additionally, genes exclusively found in oocytes (224) and blastocysts (2,200) with specific biological functions were identified. Gene co-expression network and module preservation analysis revealed strong preservation of functional modules related to exosome components, steroid metabolism, cell proliferation, and morphogenesis. However, cell cycle and amino acid transport modules exhibited weak preservation, which may reflect differences in embryo development kinetics and the activation of cell signaling pathways between buffalo and bovine. This comprehensive transcriptomic profile serves as a valuable resource for assessing the molecular quality of buffalo oocytes and embryos in future in vitro embryo production assays. technologies efficiency RNAseq RNA seq highthroughput high throughput analyses Bubalus bubalis, bubalis , bubalis) coexpression co Complexes slaughterhousederived slaughterhouse derived ovaries 616 (616 526. 526 . (526) 72%, 72 (72% 334 3 34 ±3.3 sd 21.3%, 213 21 (21.3% 418 4 18 ±4.1 41 7 grade 2 13976 13 976 13,97 62 8,649. 8649 8,649 8 649 (8,649) them 4,153 4153 153 (4,153 foldchange fold change 11 BMP15, BMP15 BMP (BMP15 UCHL1 UCHL WEE1 WEE NLRPs KPNA7 KPNA ZP2 ZP ZP4 APOA1, APOA1 APOA (APOA1 KRT18 KRT ANXA2 ANXA S100A14 SA S A SLC34A2 SLCA SLC PRSS Additionally 224 (224 2,200 2200 200 (2,200 components metabolism proliferation morphogenesis However bovine assays 61 (61 52 (526 72% (72 33 ±3. 21.3% (21.3 ±4. 1397 97 13,9 6 864 8,64 64 (8,649 4,15 415 15 (4,15 BMP1 (BMP1 (APOA KRT1 S100A1 SLC34A 22 (22 2,20 220 20 (2,20 (6 5 (52 (7 ±3 21.3 (21. ±4 139 9 13, 86 8,6 (8,64 4,1 (4,1 (BMP S100A (2 2,2 (2,2 ( (5 ± 21. (21 8, (8,6 4, (4, 2, (2, (8, (4 (8

Abstract This conference celebrates the 40th anniversary of AETE. Over the past 40 years, AETE has served as a forum for scientists, practitioners, and students working in assisted animal reproduction in livestock species. AETE conferences have reflected developments in the field, from basic to applied science, as well as regulatory changes in assisted animal reproduction practices. Europe has led the way in these developments for many years, progressing from artificial insemination, embryo transfer, and cryopreservation to semen sexing, in vitro production of embryos, cloning by nuclear transfer, genomic selection, and the rescue of highly endangered species. These significant contributions were made possible by the support of funding agencies, both at the national and European levels, promoting cooperation between scientists and practitioners. Assisted reproduction, and animal breeding more generally, face opposition from various groups, including animal rights activists, vegetarians, proponents of organic farming, environmentalists, certain political parties, and increasing regulatory burdens. These challenges seriously affect funding for scientific research, the work of practitioners, and the breeding industry as a whole. It is crucial to invest time and resources in communication to remind the public, politicians, and regulators of the achievements in this field and the contributions made to the food supply chain and the care of the rural and natural environment. th 4 years practitioners species science practices insemination transfer sexing embryos selection agencies levels generally groups activists vegetarians farming environmentalists parties burdens research whole public politicians environment

Abstract This study explored the migration of follicular fluid (FF)-derived extracellular vesicles (EVs) of the uterine environment to the bloodstream and their interaction with neutrophils in vivo and in vitro. For the in vivo experiment, six Nellore heifers (Bos indicus) received an intrauterine infusion seven days after ovulation with 1X PBS only (sham group; n=1), 1X PBS stained with lipophilic dye PKH26 (control group; n=2), or FF-derived EVs stained with PKH26 (treated group; n=3). Plasma was collected at 0, 10, 30, 60-, 180-, 360-, 720-, and 1440-min post-infusion to obtained EVs for analysis by nano flow cytometry. Labeled EVs were present in the bloodstream at 30- and 60-min post-infusion in the treatment group. Additionally, plasma derived-EVs from all groups were positive for Calcein-AM, Alix, Syntenin, and Calnexin, which confirm the presence of EVs. The second experiment utilized the plasma-derived EVs from the heifers from 30 and 60 min timepoints to evaluate if neutrophils can uptake EVs in vitro. As results, it was possible to observe the presence of labeled EVs in neutrophils treated with plasma derived-EVs from the treatment group. In summary, our results suggest that labeled EVs can migrate from the uterine environment rapidly and interact with circulating immune cells in bovine. FFderived FF derived (EVs vitro Bos indicus X sham group n=1, n1 n n=1 , 1 n=1) PKH PKH2 control n=2, n2 n=2 2 n=2) n=3. n3 n=3 . 3 n=3) 0 10 60, 60- 180, 180 180- 360, 360 360- 720, 720 720- 1440min 1440 postinfusion post cytometry 60min Additionally derivedEVs CalceinAM, CalceinAM Calcein AM, AM Calcein-AM Alix Syntenin Calnexin plasmaderived 6 summary bovine n= 18 36 72 144 7 14

Abstract The path to fertility in the mare requires an understanding of the hormonal influences, the immune response, genetics, and epigenetic mechanisms involved not only in physiological reproductive processes, but also such pathologies as endometritis and endometrosis. Endometritis may lead to endometrosis establishment. In the presence of endometritis, neutrophils arrive at the mare endometrium, and form neutrophil extracellular traps. While NETosis plays pivotal roles, prolonged inflammation can lead to chronic endometritis, endometrosis, and fertility issues. Matrix metalloproteinases and epigenetic changes influence the course of endometrosis. Inhibitors of specific enzymes involved in NETosis and epigenetic inhibitors have shown potential in reducing pro-fibrotic effects. Collagen type III (COL3) has emerged as a putative biomarker, correlating with endometrosis and useful in fertility assessment. Thus, COL3 may offer a non-invasive diagnostic tool, as a complement to histopathological methods. Epigenetic modifications and miRNA expressions offer new avenues for therapeutic strategies, emphasizing the importance of understanding the cellular mechanisms at play in mare endometrial fibrosis. influences response genetics processes establishment endometrium traps roles issues profibrotic pro fibrotic effects COL (COL3 biomarker assessment Thus noninvasive non invasive tool methods strategies fibrosis (COL

Abstract The oviduct and uterus provide an optimal environment for early embryo development, where effective communication between the embryo and the maternal reproductive tract is crucial for establishing and maintaining pregnancy. Oviductal and uterine-derived EVs play pivotal roles in this maternal-embryonic communication and in facilitating early embryo development. However, despite the ability of in vitro culture methods to produce viable embryos, the lack of exchange between the embryo and the mother often results in lower-quality embryos than those derived in vivo. Therefore, there is a pressing need to increase our understanding of the physiological mechanisms underlying embryo interaction with the oviduct and endometrium through EVs and to develop models capable of mimicking the in vivo environment. This review aims to provide up-to-date insights into the communication between the mother and pre-implantation bovine embryo, exploring their applications and perspectives in the field. development pregnancy uterinederived uterine maternalembryonic embryonic However lowerquality lower quality Therefore uptodate up date preimplantation pre implantation field

Abstract This review elucidates the physiological and endocrinological processes intrinsic to puberty and ovulation induction protocols in Bos indicus and Bos taurus beef heifers. Puberty is a complex physiological event involving gonadotropic and metabolic changes that lead to sexual maturity, first ovulation, and regular reproductive cycles, enabling females to reproduce. Exposure to progesterone-based hormonal protocols, with or without additional hormones, can reduce the age at first ovulation and improve sexual maturity through stimuli in the hypothalamus-pituitary-gonadal (HPG) axis and uterine development. However, inducing puberty differs from inducing ovulation, as it does not ensure the heifer will continue cycling or be ready to establish and maintain pregnancy after hormonal exposure. Regardless of the pharmacological basis, studies consistently report that beef heifers that had a corpus luteum (CL) prior to the timed-artificial insemination (TAI) protocol, have greater expression of estrus in response to synchronization and greater pregnancy per AI compared to heifers without a CL. The combination of P4 and E2 significantly impacts uterine development, increasing reproductive efficiency. Exposure to P4 causes a positive effect on inducing ovulation. However, studies indicate that the addition of E2 esters at the time of P4 device removal increases the ovulation rate. In general, the studies showed that fertility varied according to the type of the ovulation induction protocol used, but with inconsistent results. Although ovulation induction protocols are strategic tools to accelerate sexual maturity, a holistic view of the entire system is extremely important, combining integration with genetics and nutrition to enhance the reproductive outcomes of beef heifers. Future research is needed to understand and refine these protocols, driving the efficiency of beef cattle production systems. cycles reproduce progesteronebased progesterone based hormones hypothalamuspituitarygonadal hypothalamus pituitary gonadal HPG (HPG development However exposure basis CL (CL timedartificial timed artificial TAI (TAI P E rate general used results important systems

Abstract Gene editing technologies have revolutionized the field of livestock breeding, offering unprecedented opportunities to enhance animal welfare, productivity, and sustainability. This paper provides a comprehensive review of recent innovations and applications of gene editing in livestock, exploring the diverse applications of gene editing in livestock breeding, as well as the regulatory and ethical considerations, and the current challenges and prospects of the technology in the industry. Overall, this review underscores the transformative potential of gene editing in livestock breeding and its pivotal role in shaping the future of agriculture and biomedicine. welfare productivity sustainability considerations industry Overall biomedicine

Abstract The productivity of the beef and dairy industries depends directly on the reproductive efficiency and genetic gain of the herd, which are directly associated with the appropriate use of Assisted Reproductive Technologies (ARTs). The objective of this review is to show from a Brazilian perspective the evolution over the last 40 years of ARTs related to ovulation resynchronization programs and embryo transfer in cattle. Despite significant improvements and high fertility obtained in timed artificial insemination (TAI) protocols (Sales et al., 2024 - Part I), the improvement of the use of in vitro-produced embryos, development of resynchronization programs, and the advance in Doppler ultrasonography (Doppler-US) for reproductive assessments of bovine females were the ARTs that presented the greatest relevance on reproductive effectiveness in cattle. In the last seven years, the embryo transfer (ET) technology using in vitro-produced (IVP) embryos took over the conventional ET of in vivo produced embryos after donor’s superovulation. Also, procedures and pregnancy rates after ET of IVP embryos were improved in dairy and beef operations. The Doppler-US allows the identification of non-pregnant females at an early stage based on the evaluation of blood perfusion of the corpus luteum. Recent studies in beef and dairy cows indicate satisfactory accuracy when Doppler-US is used at 20-22 days after TAI. Consequently, super-early resynchronization programs have been developed and are being implemented in commercial programs, thereby facilitating earlier conception through the use of semen from superior bulls, providing genetic and economic improvements in herds. Likewise, the assessment of luteal function by Doppler-US allows the selection of embryo recipients with greater receptivity, and consequently may increase the effectiveness of timed ET programs. herd ARTs. . (ARTs) 4 cattle TAI (TAI Sales al al. 202 I, I , I) vitroproduced vitro DopplerUS US (Doppler-US (ET (IVP donors donor s superovulation Also operations nonpregnant non pregnant luteum 2022 20 22 20-2 Consequently superearly super bulls herds Likewise receptivity (ARTs 2 20-

Abstract Intracytoplasmic Sperm Injection (ICSI) has increased usage in cases of stallion fertility issues, particularly for older stallions, those with reduced sperm numbers or quality, or stallions that have passed away, and only a limited amount of frozen semen is available. By manipulating the frozen semen through thawing, diluting, and refreezing or by cutting the straw under liquid nitrogen, the supply of semen for ICSI can be extended. While ICSI requires a minimal number of spermatozoa per procedure, it is important to consider sperm quality as a crucial factor affecting fertilization and embryo development. Although it is possible to produce healthy embryos and offspring from low quality sperm samples, it is preferable to process and select morphologically and functionally superior sperm to maximize the chances of successful fertilization and embryo development. Several techniques are available for selecting the spermatozoa for ICSI, such as swim-up, washing, density gradient centrifugation, microfluidic sorting, and some combinations. In this review, we will focus on semen type, handling, recent breakthroughs, stallion effects on ICSI efficiency and the prospects of this technology within the equine industry. (ICSI issues away thawing diluting nitrogen extended procedure development samples swimup, swimup swim up, up swim-up washing centrifugation sorting combinations review type handling breakthroughs industry

Abstract Polyethylenimine (PEI) has been explored as an efficient non-viral system for delivering genes to cells; however, there were no protocols for its use in porcine fetal fibroblasts (PFF). Therefore, we compared different concentrations of FITC-PEI (0.625, 1.25, 2.5, 5, 10, 20, 40, or 80 µg/mL) and incubation times (30 min, 1 h, or 2 h). It was observed that the incubation time did not affect the internalization of the PEI-FITC and that 30 min was sufficient to capture the complex. The concentrations higher than 10 µg/mL could reach many marked PFF (>90%). Then, two PEI concentrations were tested, 10 or 40 µg/mL, combined with an N/P of 2 with the pmhyGENIE-5 for 30 min. The percentage of PFF-GFP positive was similar between the PEI concentrations in the evaluation time points (24 h, 48 h, and 72 h). However, 40 µg/mL caused higher membrane damage rates. Thus, it can be concluded that concentrations between 10 – 80 µg/ml of PEI promote high incorporation rates, even in periods as short as 30 minutes. Furthermore, it can be stated that the transfection condition used in Polyplexes 1 (10 µg/mL of PEI and 37.5 µg/mL of pmhyGENIE-5 for 30 min) efficiently produces genetically edited porcine fetal fibroblasts with low cell damage. (PEI nonviral non viral cells however PFF. . (PFF) Therefore FITCPEI FITC 0.625, 0625 0 625 (0.625 125 25 1.25 5 2.5 20 8 µgmL µg mL (3 h h. h) PEIFITC 3 complex >90%. 90 >90% (>90%) Then tested 4 NP N P pmhyGENIE5 pmhyGENIE pmhyGENIE- PFFGFP GFP 24 (2 7 However rates Thus µgml ml minutes Furthermore (1 375 37 37. (PFF 0.625 062 62 (0.62 12 1.2 2. ( 9 >90 (>90% 0.62 06 6 (0.6 1. >9 (>90 0.6 (0. > (>9 0. (0 (>

Abstract Tadalafil, a potent phosphodiesterase inhibitor 5 (PDE-5), is commonly used for the management of erectile dysfunction. However, its therapeutic potential extends beyond this indication. This study aimed to investigate the impact of tadalafil on the recovery of testicular parenchyma in male Wistar rats exposed to testicular thermal stress. Fifty-four Wistar rats were subjected to testicular thermal stress and randomly assigned to receive either tadalafil treatment (TAD) or no treatment (control). TAD was administered intraperitoneally at a dose of either 0.9 mg/kg or 1.8 mg/kg. Biometric parameters, histopathological assessment of the testis, serum testosterone levels, oxidative stress, and interleukin levels were evaluated on days 7, 15, and 30 after thermal shock. The animals were euthanized at the end of each experimental period, and samples were collected. TAD treatment maintained testicular weight and reduced the testicular degenerative process up to day 7 post-injury. However, despite TAD therapy, serum testosterone levels were decreased in the treated groups at days 7 and 15 post-thermal stress. TAD also decreased TNF-α and NO levels at different doses but had no effect on IL-6. The treatment with TAD after heat shock demonstrated anti-inflammatory and antioxidant properties but did not prevent the aggravation of testicular lesions in subsequent periods, even with the systematic reduction in TNF-α and NO levels. Therefore, this selective PDE-5 inhibitor, at the dosages used, did not have a positive impact on testosterone levels during the post-thermal stress period, which could compromise the resumption of the spermatogenic process. Tadalafil PDE5, PDE5 PDE , (PDE-5) dysfunction However indication Fiftyfour Fifty four (TAD control. control . (control) 09 0 9 0. mgkg mg kg 18 1 8 1. parameters testis 3 period collected postinjury. postinjury post injury. injury post-injury therapy postthermal TNFα TNF α IL6. IL6 IL 6. 6 IL-6 antiinflammatory anti inflammatory periods Therefore PDE- (PDE-5 (control IL- (PDE- (PDE