Cryopreservation of spermatozoa is becoming more important because of new clinical requirements and current clinical practice. Despite the success of sperm cryopreservation this routinely used procedure induces serious detrimental changes in sperm function. Some researchers believe that cryopreservation is associated with DNA fragmentation and DNA single strand breaks in sperm. Mechanisms of cryodamage to human spermatozoa are thought to be multifactorial including: cold shock, osmotic stress, intracellular ice crystal formation, oxidative stress, and combinations of these conditions. Additives showing antioxidative properties reported to reduce the impact of ROS-induced and cold shock damages. Many studies exist as regards the effects of antioxidants on the cryopreservation aimed at improving the quality of post-thaw semen. Hence, this review will clarify results of recent applications of various antioxidants used in numerous research efforts to improve cryopreservation of spermatozoa. This review is to increase the understanding of the roles of these antioxidants concerning mechanisms which enhance resistance to cryodamage of spermatozoa.

Preconditioning of mesenchymal stem cells (MSCs) with melatonin (MT) has shown promising results in animal models of myocardial infarction, renal ischemia and cerebral ischemia. Here, we use this strategy in the liver fibrosis induced by CCl4. There were five groups: normal, CCl4, CCl4 + vehicle, CCl4 + BMMSCs and CCl4 + MT-bone marrow (BM)-derived MSCs (MT-BMMSCs). CCl4 was injected twice weekly for 8 weeks and treatment either with cells or vehicle was performed at the beginning of week 5 with a single dose. BMMSCs were preconditioned with MT for 24 h before injection. MT-BMMSCs had a high ability of homing into the injured liver (P ≤ 0.05 vs. BMMSCs). The CCl4 + MT-BMMSCs group showed higher percentage of glycogen storage but lower percentage of collagen and lipid accumulation (P ≤ 0.05 vs. CCl4 + BMMSCs). The CCl4 + MT-BMMSCs group showed lower expressions of transforming growth factor-β1 (TGF-β1) and Bax and lower content of sera alanine aminotransferase (ALT) but higher expressions of matrix metalloproteinases (MMPs) and Bcl2 compared with the BMMSCs group (P ≤ 0.05). The results showed the better therapeutic outcomes of MT preconditioning by probably improving cell homing and also better maintenance of the balance between matrix degrading and accumulating factors.

Biochemical and physical modifications during the freeze-thaw process adversely influence the restoration of energy-dependent sperm functions required for fertilization. Resveratrol, a phytoalexin, has been introduced to activate 5' AMP-activated protein kinase which is a cell energy sensor and a cell metabolism regulator. The cryoprotection of resveratrol on sperm cryoinjury via activation of AMP-activated protein kinase also remains to be elucidated. Our aim, thus, was to investigate: (i) the presence and intracellular localization of AMP-activated protein kinase protein; (ii) whether resveratrol may exert a protective effect on certain functional properties of fresh and post-thaw human spermatozoa through modulation of AMP-activated protein kinase. Spermatozoa from normozoospermic men were incubated with or without different concentrations of Compound C as an AMP-activated protein kinase inhibitor or resveratrol as an AMP-activated protein kinase activator for different lengths of time and were then cryopreserved. AMP-activated protein kinase is expressed essentially in the entire flagellum and the post-equatorial region. Viability of fresh spermatozoa was not significantly affected by the presence of Compound C or resveratrol. However, although Compound C caused a potent inhibition of spermatozoa motility parameters, resveratrol did not induce negative effect, except a significant reduction in motility at 25 μm for 1 h. Furthermore, resveratrol significantly increased AMP-activated protein kinase phosphorylation and mitochondrial membrane potential and decreased reactive oxygen species and apoptosis-like changes in frozen-thawed spermatozoa. Nevertheless, it was not able to compensate decreased sperm viability and motility parameters following cryopreservation. In contrast, Compound C showed opposite effects to resveratrol on AMP-activated protein kinase phosphorylation, reactive oxygen species, apoptosis-like changes, mitochondrial membrane potential, and motility parameters. These findings, although preliminary, suggest that resveratrol-induced improvement of cryopreserved sperm functions may be mediated through activation of AMP-activated protein kinase, indicating the importance of AMP-activated protein kinase activity for human spermatozoa functions. Further investigations are required to elucidate the mechanism by which resveratrol ameliorates oxidative stress-mediated damages in an AMP-activated protein kinase-dependent mechanism.

The heterogeneous and multifactorial essence of polycystic ovary syndrome (PCOS) renders a remarkable significance to microRNAs (miRNAs). Normo-androgenic (NA) and hyperandrogenic (HA) PCOS patients were compared with matched healthy women. Expression of miRNAs and TGFβ signaling genes was studied by qRT-PCR and western blotting. Effect of androgen on expression of miR-93 and miR-21 and involvement of androgen receptor were appraised. In granulosa cells (GCs), miR-93 and miR-21 showed significantly increased levels in HA patients compared to NA patients. On the contrary, follicular fluid (FF) levels of both miRNAs were significantly decreased in HA group compared to control women. No significant change in the expression of miRNAs in serum samples was detected. Furthermore, mRNA levels of SMAD7 and TGFBR2 were significantly downregulated in GCs of HA group compared to NA and control subjects. TGFBR2 protein level was significantly decreased in HA patients compared to controls. Free testosterone and free androgen index were positively correlated with expression of miR-93 and miR-21 in GCs of PCOS group. Our findings show distinct molecular signature of different subtypes of PCOS. Intermediary position of miRNAs as androgen responsive factors may play critical role in the pathogenesis of PCOS in hyperandrogenic condition.

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Stromal cell-derived factor-1α (SDF-1α) has been known to implicate in homing of MSCs, and resveratrol has been reported to have a positive influence on SDF-1 level in the site of injury. In this study, a combined strategy was applied to evaluate bone marrow-derived MSCs (BMSCs) homing to the rat model of liver cirrhosis induced by common bile duct ligation (CBDL): (1) pretreatment delivery of resveratrol into the cirrhotic liver, and (2) transplantation of ex vivo BMSC preconditioning with SDF-1α. BMSCs were preconditioned with 10 ng/µL SDF-1α for 1 h and then labeled with the CM-Dil. Cirrhosis was induced by CBDL. Animals received intraperitoneal injection of resveratrol for 7 days, started on day 28 of CBDL post-operative. On day 36 post-operative, 1 × 10 of SDF-1α-preconditioned BMSCs was injected via caudal vein. Animals were sacrificed at 72 h post-cell transplantation. Immunofluorescence and flow cytometry assessments showed that the BMSC+SDF+RV group had an increased rate of homing into the liver, but it had a decreased rate of homing into the lung and spleen, as compared with the other groups (P < 0.05). The BMSC+SDF+RV group showed high protein expression of SIRT1, but low protein expression of p53 in the liver (P < 0.05 vs other groups). CXCR4 and matrix metalloproteinase (MMP)-9 highly expressed in SDF-1α-preconditioned BMSCs in vitro, and that AKTs and CXCL12 expressed in injured liver undergoing resveratrol injection. Our findings suggest that reseveratrol pretreatment prior to SDF-1α preconditioning could be a promising strategy for designing cell-based therapies for liver cirrhosis.

A significant dysregulation of miR-145 and miR-182 in GLCs of PCOS may indicate their involvement in pathogenesis of PCOS. Differential up-regulation of miR-182 in FF of PCOS patients with its promising predictive values for discrimination of PCOS reinforced the importance of studying miRNAs' profile in FF.

This work aimed at investigating the effect of resveratrol on (1) DNA integrity and (2) fertilizing capacity of sperm by quantifying the presence of key paternal transcripts considered as markers for male fertility (protamine 1 [PRM1] and protamine 2 [PRM2]) and pregnancy success (adducin 1 alpha [ADD1]) in cryopreserved human spermatozoa through modulation of AMP-activated protein kinase (AMPK). The study populations was drawn from 22 normozoospermic healthy volunteers which were incubated with or without AMPK activator (resveratrol [RSV], 15 µM) or inhibitor (Compound C [CC], 30 µM) for 1 h and were then cryopreserved. Untreated frozen-thawed spermatozoa served as controls. The RSV-induced AMPK activation decreased the level of DNA fragmentation in comparison with the control (21.18 ± 0.92 vs. 22.50 ± 0.40; p < 0.01). The relative mRNA expression levels of protamines (1 and 2) and ADD1 in RSV pretreated frozen-thawed human spermatozoa were also improved significantly compared to the control (p < 0.05). Conversely, the inhibitory effect of CC on AMPK activity deteriorated the deleterious effects of cryopreservation on these parameters (p < 0.01). In conclusion, these results demonstrated the cryoprotective effect of the RSV-induced increase in AMPK activity on DNA integrity and key paternal transcripts of cryopreserved human spermatozoa. These findings are of great importance for improving the available cryopreservation protocols in terms of the number of lesions that produced over key genes and the dramatic effects on sperm DNA fragmentation.