Tetrazolium Salt WST-8 as a Novel and Reliable Chromogenic Indicator for the Assessment of Boar Semen Quality

Paclitaxel inhibits proliferation by negatively regulating Cdk1-cell cycle axis in rat airway smooth muscle cells

OBJECTIVE

Paclitaxel exhibits outstanding biological activities in inhibiting cell proliferation and inducing cell apoptosis. However, the effects of paclitaxel on airway smooth muscle cells (ASMCs) have not been reported yet. The purpose of this study is to determine the effects of paclitaxel on the proliferation and apoptosis of ASMCs.

METHODS

Rat primary ASMCs were isolated and used in all the experiments. Cell Counting Kit-8 assay and Edu assay were used to analyze the cell viability and proliferation, respectively. Flow cytometry was used to detect the cell cycle and apoptosis. Quantitative real-time PCR (qRT-PCR), western blotting, and immunostaining were used to detect the expression of cyclin-dependent kinase 1 (Cdk1).

RESULTS

Our study showed that paclitaxel inhibits the proliferation of ASMCs in a dose- and time-gradient-dependent manner. Further study displayed that cell cycle is arrested at G2/M phase. And Cdk1 was dramatically down-regulated by paclitaxel treatment. Cell morphological analysis showed that ASMCs are elliptical with a larger surface area after paclitaxel treatment. Nucleus morphological analysis showed that the nuclei are in a diffuse state after paclitaxel treatment. However, paclitaxel did not induce the apoptosis of ASMCs.

CONCLUSIONS

Our study demonstrated that paclitaxel inhibits the proliferation of ASMCs at least partly by negatively regulating Cdk1-cell cycle axis.

A microplate-based DCFH-DA assay for the evaluation of oxidative stress in whole semen

Aims

The well-documented relationship between sperm oxidation and male infertility strongly encourages the development of assays for reactive oxygen species detection in semen samples. The present study aims to apply the microplate-based 2',7'-dichlorofluorescein diacetate assay to the evaluation of oxidative stress in unprocessed whole semen, thus avoiding sample centrifugations and other manipulations that may cause significant reactive oxygen species increments.

Main methods

The fluorescence assay consisted in the quantification of both intracellular and extracellular reactive oxygen species levels in unwashed semen specimens by using the probe 2',7'-dichlorofluorescein diacetate into a 96-well plate. The method was useful for the preliminary assessment of the oxidation levels of whole semen samples from men undergoing standard sperm analysis as well as to evaluate the effect of some pro-glutathione molecules on semen oxidative status.

Key findings

The 2',7'-dichlorofluorescein diacetate assay was successfully adapted to the evaluation of oxidative stress in whole semen, effectively revealing the perturbation of the redox homeostasis of the sample. Accordingly, specimens with abnormal sperm parameters (n = 10) presented oxidation indexes significantly higher than those with normospermia (n = 10) [7729 (range 3407-12769) vs. 1356 (range 470-2711), p < 0.001]; in addition, semen oxidation indexes negatively correlated to sperm motility and morphology. Noteworthy, whole semen exposure to pro-glutathione compounds led to reduced semen oxidation levels and sperm protection against oxidative damage.

Significance

Based on our pilot experimental data, the microplate-based 2',7'-dichlorofluorescein diacetate assay appears to be a convenient method for the detection of reactive oxygen species levels in whole semen samples, avoiding artifacts due to semen centrifugation steps. At the same time, the test could be a helpful tool for the basic and quick screening of antioxidant molecules able to preserve semen quality.

Beneficial Influence of Soybean Lecithin Nanoparticles on Rooster Frozen-Thawed Semen Quality and Fertility

Simple Summary

Soy lecithin (SL) can be used in to prevent spermatozoa cryodamage during cryopreservation by mitigating the efflux of cholesterol or phospholipids, thus reducing the formation of intracellular ice crystals. SL nanoparticles (nano-SL) have a smaller particle size and higher solubilizing capacity as compared with those that have not undergone nanotreatment. Thus, they allow for a better interaction or coating of sperm, decreasing cold shock injury during freezing–thawing processes. The objective of this study was to determine the optimal concentration of nano-SL. In order to achieve this, we assessed the quality of frozen–thawed semen in vitro and in vivo. We found that a nano-SL dosage of 1.0% in the semen extender had an affirmative influence on post-thawing quality in roosters, improving various parameters related to sperm motion, protecting the membrane and acrosome integrities, increasing mitochondrial activity and antioxidant capacity, and reducing the oxidative stress caused by the cryopreservation process. Moreover, enrichment of 1.0% nano-SL in the semen extender improved the fertilizing capacity of rooster sperm after artificial insemination.

Abstract

The present study aimed to investigate the impact of different concentrations (0%, 0.5%, 1.0%, 1.5%, and 2.0%) of nano-soybean lecithin (SL) in the extender on sperm quality, sperm motion characteristics, and fertility outcomes of post-thawed rooster semen. Adult Ross broiler breeder roosters (n = 20) were subjected to semen collections twice a week for three weeks. At each collection, semen samples were pooled and allocated into five treatments corresponding to different nano-SL concentrations (control, SL0.5, SL1.0, SL1.5, and SL2.0). Sperm parameters, including motility (collected using a computer-assisted sperm analysis system), plasma membrane and acrosome integrities, and mitochondrial activity were assessed. Sperm malondialdehyde (MDA) and antioxidant activities (total antioxidant capacity (TAC); superoxide dismutase (SOD); glutathione peroxidase (GPx)) were evaluated. The fertility and hatchability obtained with frozen–thawed rooster semen supplemented with the optimum nano-SL concentration were assessed after artificial insemination. The results showed that the addition of 1% nano-SL into the extender led to a higher semen motility in roosters, improved plasma membrane and acrosome integrities, and higher mitochondrial activity of post-thawed rooster semen in comparison to controls (p < 0.05). The MDA levels in the SL0.5 and SL1.0 groups were lower than the other groups (p < 0.05). TAC activities in SL0.5, SL1.0, and SL1.5 groups were significantly higher than those in the other groups (p < 0.05). It was observed that the concentration of SOD was higher in the SL1.0 group than in the other groups (p < 0.05). The activity of GPx was not influenced in any of the cases (p > 0.05). Moreover, the percentages of fertility and hatchability in the SL1.0 group were higher (56.36% and 58.06%) than those in the control group (42.72% and 40.43%). In summary, the addition of nano-SL to the extenders enhanced the post-thawed semen quality and fertility of roosters by reducing the level of oxidative stress. The optimum nano-SL concentration was 1.0%. These results may be beneficial for improving the efficacy of semen cryopreservation procedures in poultry breeding.