The Effect of Aging on Erectile Function Induced by Apomorphine and Electric Field Stimulation to Rat

Objective To explore the effect and mechanism of aging on erection by using rat model. Materials & Methods Forty male SD rats of 3, 9, 18 and 24 months old were divided into 4 groups equally according to their age. Apomorphine given subcutaneously and cavernous nerve electric field stimulation was used to induce erection of rats. Results The successful erection rate, number of erection times, and intracavernous pressure (ICP) in the rats of 18 and 24 month old was significantly lower than that of 3 and 9 month old. Conclusion The erectile function in aging rats is deteriorated. The damage mechanism with aging might be related to dopaminergic system in central nerves.

Early electrical field stimulation prevents the loss of spinal cord anterior horn motoneurons and muscle atrophy following spinal cord injury

Our previous study revealed that early application of electrical field stimulation（EFS） with the anode at the lesion and the cathode distal to the lesion reduced injury potential, inhibited secondary injury and was neuroprotective in the dorsal corticospinal tract after spinal cord injury（SCI）. The objective of this study was to further evaluate the effect of EFS on protection of anterior horn motoneurons and their target musculature after SCI and its mechanism. Rats were randomized into three equal groups. The EFS group received EFS for 30 minutes immediately after injury at T_（10）. SCI group rats were only subjected to SCI and sham group rats were only subjected to laminectomy. Luxol fast blue staining demonstrated that spinal cord tissue in the injury center was better protected; cross-sectional area and perimeter of injured tissue were significantly smaller in the EFS group than in the SCI group. Immunofluorescence and transmission electron microscopy showed that the number of spinal cord anterior horn motoneurons was greater and the number of abnormal neurons reduced in the EFS group compared with the SCI group. Wet weight and cross-sectional area of vastus lateralis muscles were smaller in the SCI group to in the sham group. However, EFS improved muscle atrophy and behavioral examination showed that EFS significantly increased the angle in the inclined plane test and Tarlov＇s motor grading score. The above results confirm that early EFS can effectively impede spinal cord anterior horn motoneuron loss, promote motor function recovery and reduce muscle atrophy in rats after SCI.

Relaxant effect and possible mechanism of 17-nor-subincanadine E in rabbit corpora cavernosa

Compounds with dual action on cyclic adenosine monophosphate （cAMP） and cyclic guanosine monophosphate （cGMP） may be a treatment option for erectile dysfunction, as they not only promote penile erection but also prevent the upregulation of phosphodiesterase-5. In this study, we examined the possible relaxant effect and mechanism of 17-nor-subincanadine E （SEC, 0.2-200 pmol I^-1）, a plant-derived alkaloid, in rabbit corpus cavernosum （RbCC） strips that had been precontracted by exposure to phenylephrine （10 pmol I^- 1） or a high concentration of K＋ （60 mmol I^- 1） in vitro. In addition to SEC＇s effect on cAMP and cGMP levels, electrical field stimulation （EFS） in phenylephrine-precontracted RbCC and calcium chloride （1-100 mmol I^-1） evoked responses in depolarized RbCC were analysed. SEC relaxed the phenylephrine-precontracted RbCCs in a concentration-dependent manner. Atropine, guanethidine and N-co-nitro-L-arginine methyl ester （L-NAME） did not have any effect on the relaxation of RBCCs. When 1H-1,2,4oxadiazole[4,3-a] quinoxalin-1-one （ODQ） was added, it effectively blocked the relaxant response of SEC. Although SEC enhanced the maximal relaxation produced by sodium nitroprusside （SNP） and forskolin in phenylephrine-precontracted cavernosal smooth muscle, it caused a decrease in the maximal contractile response induced by calcium chloride in depolarized RbCCs. The relaxant effect of SEC was paralleled by an increase in the tissue levels of the Cyclic nucleotides cAMP and cGMP. We conclude that SEC promotes the relaxation of RbCC, possibly favouring cAMP and cGMP accumulation and calcium blockade. This novel mechanism could be useful for patients who do not benefit from phosphodiesterase inhibitors and for those with endothelial and nitrergic dysfunction, such as patients with diabetes, hypertension and dyslipidaemias.

Synergistic stimulation of surface topography and biphasic electric current promotes muscle regeneration

Developing a universal culture platform that manipulates cell fate is one of the most important tasks in the investigation of the role of the cellular microenvironment.This study focuses on the application of topographical and electrical field stimuli to human myogenic precursor cell(hMPC)cultures to assess the influences of the adherent direction,proliferation,and differentiation,and induce preconditioning-induced therapeutic benefits.First,a topographical surface of commercially available culture dishes was achieved by femtosecond laser texturing.The detachable biphasic electrical current system was then applied to the hMPCs cultured on laser-textured culture dishes.Laser-textured topographies were remarkably effective in inducing the assembly of hMPC myotubes by enhancing the orientation of adherent hMPCs compared with flat surfaces.Furthermore,electrical field stimulation through laser-textured topographies was found to promote the expression of myogenic regulatory factors compared with nonstimulated cells.As such,we successfully demonstrated that the combined stimulation of topographical and electrical cues could effectively enhance the myogenic maturation of hMPCs in a surface spatial and electrical field-dependent manner,thus providing the basis for therapeutic strategies.