Effect of acute tadalafil on sperm motility and acrosome reaction: in vitro and in vivo studies

Effects of acute tadalafil on sperm motility and acrosome reaction were investigated, both in vitro and in vivo. Twenty asthenozoospermic and 20 normozoospermic patients as control were randomly enrolled. For in vitro part, 0.5 ml tadalafil solutions with different concentrations were added (0.2, 0.1, 0.05 and 0.025 μg ml(-1) , respectively) into semen samples. In both groups, samples treated with 0.2 μg ml(-1) tadalafil had significant increase in sperm motility after 2 h incubation. For in vivo part, oral administration of tadalafil (20 mg) or sildenafil (100 mg) was given. In both groups, computer-assisted semen analysis parameters showed no significant difference. After the administration of tadalafil (2 h) and sildenafil (1 h), there was no significant difference observed in premature acrosome reaction incidence rate. Taking both in vitro and in vivo results into consideration, acute on-demand administration of tadalafil would have no adverse effect on semen parameters.

The therapeutic effect of rosuvastatin on cardiac remodelling from hypertrophy to fibrosis during the end-stage hypertension in rats

End-stage hypertensive heart disease is an increasing cause of cardiac mortality. Therefore, the current study focused on the cardiac remodelling from hypertrophy to fibrosis in old-aged spontaneously hypertensive rats (SHRs), and explored the therapeutic effects of Rosuvastatin and its possible mechanism(s) of action. Spontaneously hypertensive rats at age 52 weeks were randomly divided into three groups, the first two to receive Rosuvastatin at a dose of 20 mg/kg/day and 40 mg/kg/day, respectively, and the third to receive placebo, which was to be compared with Wistar-Kyoto as controls. After 2-month treatment, SBP, heart to body weight ratio (HW/BW%) and echocardiographic features were evaluated, followed by haematoxylin and eosin and Masson trichrome staining in conjunction with qPCR of foetal gene expressions. Transferase-mediated dUTP nick-end labelling assay and immunofluorescent labelling for active caspase-3 were used to detect the apoptotic cardiomyocytes. Signaling pathways involved were examined by using western blot. Old-aged SHR developed end-stage hypertensive heart disease characterized by significant enhancement of HW/BW%, LVAWd and LVPWd, and decreased LVEF and LVFS, accompanied by cardiomyocytes enlargement and fibrosis along with activation of foetal gene programme. Cardiac apoptosis increased significantly during the transition process. Rosuvastatin reduced hypertrophy significantly via AT₁ Receptor-PKCβ2/α-ERK-c-fos pathway; protected myocardium against apoptosis via Akt-FOXO1, Bcl-2 family and survivin pathways and consequently suppressed the caspase-3 activity. The present study revealed that old-aged SHRs developed cardiac remodelling from hypertrophy to fibrosis via cardiac apoptosis during the end stage of hypertensive heart disease. These pathological changes might be the consequence of activation of AT₁ Receptor-PKCβ2/α-ERK-c-fos and AKT-FOXO1/Bcl-2/survivin/Caspase3 signaling. Rosuvastatin effectively attenuated the structural changes by reversing the signaling transductions involved.

Hepatoma polarization limits CD81 and hepatitis C virus dynamics

Many viruses target the polarized epithelial apex during host invasion. In contrast, hepatitis C virus (HCV) engages receptors at the basal surface of hepatocytes in the polarized liver parenchyma. Hepatocyte polarization limits HCV entry by undefined mechanism(s). Given the recent reports highlighting a role for receptor mobility in pathogen entry, we studied the effect(s) of hepatocyte polarization on viral receptor and HCV pseudoparticle (HCVpp) dynamics using real-time fluorescence recovery after photobleaching and single particle tracking. Hepatoma polarization reduced CD81 and HCVpp dynamics at the basal membrane. Since cell polarization is accompanied by changes in the actin cytoskeleton and CD81 links to actin via its C-terminus, we studied the dynamics of a mutant CD81 lacking a C-terminal tail (CD81(ΔC)) and its effect(s) on HCVpp mobility and infection. CD81(ΔC) showed an increased frequency of confined trajectories and a reduction of Brownian diffusing molecules compared to wild-type protein in non-polarized cells. However, these changes were notobserved in polarized cells. HCVpp showed a significant reduction in Brownian diffusion and infection of CD81(ΔC) expressing non-polarized cells. In summary, these data highlight the dynamic nature of CD81 and demonstrate a role for CD81 lateral diffusion to regulate HCV infection in a polarization-dependent manner.

Establishment of an animal model of extracorporeal membrane oxygenation in rabbits

OBJECTIVE

This study was undertaken to establish an animal model of extracorporeal membrane oxygenation in rabbits.

METHODS

Ten New Zealand white rabbits weighing 2573±330 g were used in this study. Extracorporeal membrane oxygenation was established in these animals through cannulation of the right carotid artery and jugular vein for arterial perfusion and venous return. The components of the perfusion circuit were specially designed. Arterial blood pressure was measured with a blood pressure meter through cannulation of the right femoral artery. The heart rate and blood gas parameters were also monitored by electrocardiography and a blood gas analyzer (Radiometer ABL800, Bronshøj, Denmark), respectively.

RESULTS

The rabbit model of extracorporeal membrane oxygenation was established successfully. The hemodynamic and blood gas parameters were changed within an acceptable range during the extracorporeal membrane oxygenation process. The specially designed miniature membrane oxygenator was sufficient to meet the extracorporeal membrane oxygenation needs in this animal model.

CONCLUSION

The rabbit model of extracorporeal membrane oxygenation established through right carotid artery and jugular vein cannulation is feasible, easily operated and economical. It is an ideal model for further research of the pathophysiology and organ protection offered through the application of extracorporeal membrane oxygenation.

Position effect variegation and epigenetic modification of a transgene in a pig model

Sequences proximal to transgene integration sites are able to regulate transgene expression, resulting in complex position effect variegation. Position effect variegation can cause differences in epigenetic modifications, such as DNA methylation and histone acetylation. However, it is not known which factor, position effect or epigenetic modification, plays a more important role in the regulation of transgene expression. We analyzed transgene expression patterns and epigenetic modifications of transgenic pigs expressing green fluorescent protein, driven by the cytomegalovirus (CMV) promoter. DNA hypermethylation and loss of acetylation of specific histone H3 and H4 lysines, except H4K16 acetylation in the CMV promoter, were consistent with a low level of transgene expression. Moreover, the degree of DNA methylation and histone H3/H4 acetylation in the promoter region depended on the integration site; consequently, position effect variegation caused variations in epigenetic modifications. The transgenic pig fibroblast cell lines were treated with DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine and/or histone deacetylase inhibitor trichostatin A. Transgene expression was promoted by reversing the DNA hypermethylation and histone hypoacetylation status. The differences in DNA methylation and histone acetylation in the CMV promoter region in these cell lines were not significant; however, significant differences in transgene expression were detected, demonstrating that variegation of transgene expression is affected by the integration site. We conclude that in this pig model, position effect variegation affects transgene expression.