Steroidogenic acute regulatory protein (StAR) gene expression construct: Development, nanodelivery and effect on reproduction in air-breathing catfish, Clarias batrachus

Synergistic effect of PS-MPs and Cd on male reproductive toxicity: Ferroptosis via Keap1-Nrf2 pathway

It has been wildly reported that microplastics (MPs) can adsorb heavy metals and act as carriers for their transport into organisms. However, the combined toxicity of MPs and heavy metals remains poorly studied. In this study, we established single or co-exposure (i.e. complex/combined exposure) mice models to investigate the combined toxicity of MPs and cadmium (Cd) on male reproduction. The complexation of MPs and Cd enhanced the bioavailability of Cd, while the combination of MPs and Cd exerted synergistic effect. Ultimately, the co-exposure was reported to enhance the reproduction toxicity by single exposure, which reflected in testicular structure, spermatogenesis and sex hormone synthesis. More in-depth mechanistic investigation suggested that MPs and Cd synergistically inhibited the Keap1-Nrf2 pathway and its downstream genes, induced lipid peroxidation and ferroptosis, ultimately caused damage to reproductive structures and functions. Our results highlighted the synergistic effect of MPs and Cd on the reproductive toxicity in male mammals for the first time, which also provided valuable insights into the combined toxicity mechanisms of MPs and other pollutants.

CT, Kumar P, Babu P. G, Walke P, Nayak SK, Sharma R. Teleost Nonapeptides, Isotocin and Vasotocin Administration Released the Milt by Abdominal Massage in Male Catfish, Clarias magur

In the present work the nonapeptides i.e., isotocin and vasotocin alone or in a combination were tested in C. magur to evaluate their effect on stripping by abdominal massage. Also, we used chitosan-carbon nanotube nanocomposites to conjugate the nonapetides isotocin (abbreviated as COOH-SWCNTCSPeP) and isotocin and vasotocin (COOH-SWCNTCSPePs) with the aim of sustaining the effect for a longer duration. The conjugation of nonapeptides with nanocomposites was confirmed by Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Two experiments were conducted to study the effect of naked (without nanoparticles) and conjugated nonapeptides on the milt release by stripping. Both the experiments consisted of eight treatments which included four naked groups two nanoconjugated groups and two controls. Both naked and nonconjugated formulations were successful in stripping the male catfish. The mRNA expression of selected reproductive genes was analysed to decipher the effect of nanopeptides at the molecular level. Nonapeptide treatment either naked or nanoconjugated, resulted in the upregulation of the transcript level of genes. Histological analysis revealed the concentration of spermatozoa was more in peptide injected groups than in the controls. The synergistic effects of nonapeptides and Ovatide had a positive impact on GSI. Thus, the present formulations were successful in stripping the male catfish to obtain the milt with significant reproductive success. Even though the naked groups perform better but the number of males required to fertilize the eggs in nanoconjuagted groups was smaller making it worth using for the delivery of nonapeptides.

Differential expression analysis and identification of sex-related genes by gonad transcriptome sequencing in estradiol-treated and non-treated Ussuri catfish Pseudobagrus ussuriensis

The Ussuri catfish (Pseudobagrus ussuriensis) has an XX/XY sex determination system but its sex determination gene(s) remain unknown. To better understand the molecular sex determination mechanism, transcriptome analysis was conducted to obtain sex-related gene expression profiles. Transcriptome analyses were made of male and female developing/differentiating gonads by high-throughput RNA sequencing, including gonads from fish given an estradiol-induced sex reversal treatment. A total of 81,569 unigenes were assembled and 39,904 were significantly matched to known unique proteins by comparison with public databases. Twenty specifically expressed and 142 differentially expressed sex-related genes were extracted from annotated data by comparing the treatment groups. These genes are involved in spermatogenesis (e.g., Dnali1, nectin3, klhl10, mybl1, Katnal1, Eno4, Mns1, Spag6, Tsga10, Septin7), oogenesis (e.g., Lagr5, Fmn2, Npm2, zar1, Fbxo5, Fbxo43, Prdx4, Nrip1, Lfng, Atrip), gonadal development/differentiation (e.g., Cxcr4b, Hmgb2, Cftr, Ch25h, brip1, Prdm9, Tdrd1, Star, dmrt1, Tut4, Hsd17b12a, gdf9, dnd, arf1, Spata22), and estradiol response (e.g., Mmp14, Lhcgr, vtg1, vtg2, esr2b, Piwil1, Aifm1, Hsf1, gdf9). Dmrt1 and gdf9 may play an essential role in sex determination in P. ussuriensis. The expression patterns of six random genes were validated by quantitative real-time PCR, which confirmed the reliability and accuracy of the RNA-seq results. These data provide a valuable resource for future studies of gene expression and for understanding the molecular mechanism of sex determination/differentiation and gonadal development/differentiation (including hormone-induced sexual reversal) in Ussuri catfish. This has the potential to assist in producing monosex Ussuri catfish to increase aquacultural productivity.

Transcriptomic and biochemical effects of pycnogenol in ameliorating heat stress-related oxidative alterations in rats

BACKGROUND

Heat stress is a condition that is due to extreme heat exposure. It occurs when the body cannot keep its temperature healthy in response to a hot climate and associated with oxidative stress. Testicular hyperthermia can induce apoptosis of sperm cells, affect sperm production and decrease sperm concentration, leading to sperm disorder, for this reason, we examined the protective impact of pycnogenol that it has a wide range of biological benefits, including antioxidant, anti-inflammatory and anti-cancer activities against the oxidative alterations that happen in testicular and brain tissues due to heat stress in rats.

STUDY DESIGN

Forty-eight Wistar male rats, approximately around 6 weeks age were allocated randomly into four groups (12 in each) of control, HS (subjected to heat stress and supplemented orally with 50 mg of pycnogenol/kg b. w./day dissolved in saline for 21 days), and pycnogenol (rats supplemented orally with 50 mg of pycnogenol/kg b. w./day dissolved in saline for 21 days).

RESULTS

Data revealed a promising role of pycnogenol as an antioxidant, natural product to successfully reverse the heat-induced oxidative alterations in testicular and brain tissues of rats through significant upregulation of superoxide dismutase-2, catalase, reduced glutathione, and anti-apoptotic gene, while downregulating pro-apoptotic, and heat shock protein70. Pycnogenol treatment also reversed the reproductive hormone level and spermatogenesis to their normal values.

CONCLUSION

Pycnogenol as a natural protective supplement could recover these heat stress-induced oxidative changes in testes and hypothalamus.

Chitosan-Based Drug Delivery System: Applications in Fish Biotechnology

Chitosan is increasingly used for safe nucleic acid delivery in gene therapy studies, due to well-known properties such as bioadhesion, low toxicity, biodegradability and biocompatibility. Furthermore, chitosan derivatization can be easily performed to improve the solubility and stability of chitosan-nucleic acid polyplexes, and enhance efficient target cell drug delivery, cell uptake, intracellular endosomal escape, unpacking and nuclear import of expression plasmids. As in other fields, chitosan is a promising drug delivery vector with great potential for the fish farming industry. This review highlights state-of-the-art assays using chitosan-based methodologies for delivering nucleic acids into cells, and focuses attention on recent advances in chitosan-mediated gene delivery for fish biotechnology applications. The efficiency of chitosan for gene therapy studies in fish biotechnology is discussed in fields such as fish vaccination against bacterial and viral infection, control of gonadal development and gene overexpression and silencing for overcoming metabolic limitations, such as dependence on protein-rich diets and the low glucose tolerance of farmed fish. Finally, challenges and perspectives on the future developments of chitosan-based gene delivery in fish are also discussed.

CeO2NPs relieve radiofrequency radiation, improve testosterone synthesis, and clock gene expression in Leydig cells by enhancing antioxidation

Introduction: The ratio of Ce³⁺/Ce⁴⁺ in their structure confers unique functions on cerium oxide nanoparticles (CeO₂NPs) containing rare earth elements in scavenging free radicals and protecting against oxidative damage. The potential of CeO₂NPs to protect testosterone synthesis in primary mouse Leydig cells during exposure to 1,800 MHz radiofrequency (RF) radiation was examined in vitro. Methods: Leydig cells were treated with different concentrations of CeO₂NPs to identify the optimum concentration for cell proliferation. The cells were pretreated with the optimum dose of CeO₂NPs for 24 hrs and then exposed to 1,800 MHz RF at a power density of 200.27 µW/cm² (specific absorption rate (SAR), 0.116 W/kg) for 1 hr, 2 hrs, or 4 hrs. The medium was used to measure the testosterone concentration. The cells were collected to determine the antioxidant indices (catalase [CAT], malondialdehyde [MDA], and total antioxidant capacity [T-AOC]), and the mRNA expression of the testosterone synthase genes (Star, Cyp11a1, and Hsd-3β) and clock genes (Clock, Bmal1, and Rorα). Results: Our preliminary result showed that 128 μg/mL CeO₂NPs was the optimum dose for cell proliferation. Cells exposed to RF alone showed reduced levels of testosterone, T-AOC, and CAT activities, increased MDA content, and the downregulated genes expression of Star, Cyp11a1, Hsd-3β, Clock, Bmal1, and Rorα. Pretreatment of the cells with 128 μg/mL CeO₂NPs for 24 hrs followed by RF exposure significantly increased testosterone synthesis, upregulated the expression of the testosterone synthase and clock genes, and increased the resistance to oxidative damage in Leydig cells compared with those in cells exposed to RF alone. Conclusion: Exposure to 1,800 MHz RF had adverse effects on testosterone synthesis, antioxidant levels, and clock gene expression in primary Leydig cells. Pretreatment with CeO₂NPs prevented the adverse effects on testosterone synthesis induced by RF exposure by regulating their antioxidant capacity and clock gene expression in vitro. Further studies of the mechanism underlying the protective function of CeO₂NPs against RF in the male reproductive system are required.

Developmental and epigenetic effects of Roundup and glyphosate exposure on Japanese medaka (Oryzias latipes)

Roundup and other glyphosate-based herbicides are the most commonly used herbicides in the world, yet their effects on developing fish embryos are not clearly understood. The present study, therefore, examined developmental teratogenic effects and adult-onset reproductive effects of exposure to environmentally relevant concentrations of glyphosate and Roundup in Japanese medaka fish (Oryzias latipes). Hd-rR strain medaka embryos were exposed to 0.5 mg/L glyphosate, 0.5 mg/L and 5 mg/L Roundup (glyphosate acid equivalent) for the first 15 days of their embryonic life and then allowed to sexually mature without further exposure. Whole body tissue samples were collected at 15 days post fertilization (dpf) and brain and gonad samples were collected in mature adults. Hatching success and phenotypic abnormalities were recorded up until 15 dpf. Roundup (0.5 mg/L) and glyphosate decreased cumulative hatching success, while glyphosate exposure increased developmental abnormalities in medaka fry. Expression of the maintenance DNA methyltransferase gene Dnmt1 decreased, whereas expression of methylcytosine dioxygenase genes (Tet1, Tet2 and Tet3) increased in fry at 15 dpf suggesting that epigenetic alterations increased global DNA demethylation in the developing fry. Fecundity and fertilization efficiency were not altered due to exposure. Among the reproduction-related genes in the brain, kisspeptin receptor (Gpr54-1) expression was significantly reduced in females exposed to 0.5 mg/L and 5 mg/L Roundup, and Gpr54-2 was reduced in the 0.5 mg/L Roundup treatment group. No change in expression of these genes was observed in the male brain. In the testes, expression of Fshr and Arα was significantly reduced in medaka exposed to 0.5 mg/L Roundup and glyphosate, while the expression of Dmrt1 and Dnmt1 was reduced in medaka exposed to 0.5 mg/L glyphosate. No change in expression of these genes was observed in the ovaries. The present study demonstrates that Roundup and its active ingredient glyphosate can induce developmental, reproductive, and epigenetic effects in fish; suggesting that ecological species, mainly fish, could be at risk for endocrine disruption in glyphosate and Roundup-contaminated water bodies.

Chitosan-eurycomanone nanoformulation acts on steroidogenesis pathway genes to increase the reproduction rate in fish

The study was undertaken to explore the molecular mechanism of eurycomanone, a major compound of Eurycoma longifolia plant in increasing the reproductive processes in the male fish model. Chitosan-nanoconjugated eurycomanone nanoparticles with a significant particle size [130 nm (CED1); 144.1 nm (CED2)] and stable zeta potentials (+49.1 mV and +30 mV) were synthesized and evaluated against naked eurycomanone (ED1 and ED2). In present study, short-term and long-term experiments were conducted to evaluate the effect of nano-formulation on expression of endocrine-related genes, circulating hormone concentrations (Follicle stimulating hormone, FSH; luteinizing hormone, LH; progesterone, testosterone and 17-β estradiol) and reproductive capacity of male Clarias magur. In short-term experiment, the sampling of tissues was done on hourly basis after injection of eurycomanone either alone or with chitosan and long-term experiment was carried for 21 days and in this the injection was repeated after 7 days and 14 days. Treatments CED1 and CED2 showed controlled and sustained surge of the transcript level of selected genes (except aromatase) and serum hormones (except 17β-estradiol) compared to ED1 and ED2 groups. The transcript levels of aromatase and serum 17β-estradiol hormone showed the declining trend in the chitosan conjugated groups. The gonadosomatic index (GSI), reproductive capacity, intracellular calcium and selenium and cellular structure of testes were improved in CED1 and CED2 groups compared to other treatments. Furthermore, the effect of chitosan conjugated eurycomanone was evaluated in primary testicular cells and an increase in the mRNA expression level of endocrine-related genes was detected. This is the first report of the use of chitosan conjugated eurycomanone and present study elucidates the molecular mechanism of eurycomanone in increasing the reproductive output in animals.

Molecular characterization and expression profiling of 17-beta-hydroxysteroid dehydrogenase 2 and spermatogenesis associated protein 2 genes in endangered catfish, Clarias magur (Hamilton, 1822)

The 17-beta-hydroxysteroid dehydrogenase 2 (17β-HSD2) enzyme regulates steroid levels by the inactivation of estrogen and androgens. Spermatogenesis associated protein 2 (SPATA2) plays a vital role in spermatogenesis in vertebrates including fish. We report cloning and characterization of full cds of 17β-HSD2 and SPATA2 genes in Clarias magur. The full-length cDNA sequences of 17β-HSD2 and SPATA2 were 1187 bp (ORF 1125 bp) and 1806 bp (ORF 1524 bp) encoding 375 and 508 amino acids, respectively. Signal peptide analysis revealed SPATA2 is nonsecretory, while 17β-HSD2 is a secretory protein. Hydropathy profiles showed both proteins are hydrophilic in nature. Tissue distribution of both the genes revealed high mRNA level of SPATA2 in all tissues examined indicating its wide range of expression. 17β-HSD2 indicated higher expression in preparatory phase compared to spawning phase in ovary while it was opposite in case of testis. SPATA2 showed significantly higher expression in preparatory phase compared to spawning phase in both ovary and testis. Administration of Ovatide^TM (GnRH analog) resulted in upregulation of SPATA2 expression at 6 and 16 h post-injection while 17β-HSD2 showed upregulation only at 6 h post-injection. To the best of our knowledge, this is a first report on characterization of 17β-HSD2 and SPATA2 full-length cDNA in catfish.

Ameliorative effect of chitosan-conjugated 17α-methyltestosterone on testicular development in Clarias batrachus

Chitosan nanoparticles conjugated with 17α-methyltestosterone (CS + MT) were used for studying their effect on the testicular development of Clarias batrachus during different reproductive phases. The size of chitosan nanoparticles was 127.2 nm and the nano-conjugated 17α methyltestosterone (17α-MT) was 196.1 nm (20 mg/100 ml of chitosan). Single injections of CS + MT at different doses such as 0.01, 0.1 and 0.5 μg/g body weight were administered to adults during the pre-spawning, spawning and post-spawning phase. Nano-conjugated steroid was effective at the lower dose; showing an increase in the Gonadosomatic Index (GSI) and 11-ketotestosterone level compared to the control group. Histological observations confirmed the dose-dependent advancement in spermatogenesis. These findings indicate the possibility of using CS + MT for enhancing gonadal maturity of C. batrachus.

Fabrication and characterization of chitosan conjugated eurycomanone nanoparticles: In vivo evaluation of the biodistribution and toxicity in fish

Chitosan nanoparticles (CNPs) have been proven considerable delivery agents due to their remarkable physicochemical properties. Present study reports the fabrication of CNPs by ionic gelation process and their characterization by different approaches. The constructed nanoparticles were successfully conjugated with eurycomanone with significant entrapment efficiency. Particle size of chitosan and chitosan conjugated eurycomanone nanoparticles were 126.2nm and 130nm respectively. Scanning electron microscopy showed that the particles were spherical in shape and well dispersed. Cross-linking between CNPs and eurycomanone (CENPs) were confirmed by Fourier-transform infrared (FTIR) spectroscopy. Fluorescent nanoparticles were prepared by using Rhodamine-6G dye, characterised by SEM and confirmed for conjugation by FTIR. Biodistribution of CENPs showed the presence of fluorescent nanoparticles in liver, kidney, testes and brain of C. magur. The toxicity of CENPs was evaluated by comparing the histological sections of catfish testes collected from treated and control group. No signs of toxicity were seen in testes after the delivery of CENPs. Molecular docking study revealed high spontaneous binding ability of chitosan with eurycomanone and aromatase enzyme. The study reports that CNPs can act as a stabilizing agent for eurycomanone formulation and could be a promising approach to increase the reproductive performance of the fishes.