Electrophysiological Recordings from Embryonic Mouse Motoneurons Cultured on Electrospun Poly-Lactic Acid (PLA) and Polypyrrole-Coated PLA Scaffolds

Background:Biomaterials used as cell growth stimulants should be able to provide adequate cell adhesion with no alteration in cell function. In this work, we developed a 3D model of mouse spinal cord motoneurons on scaffolds composed of electrospun PLA fibers and plasma-polymerized PPy-coated PLA fibers. Methods:The functionality of the cultured motoneurons was assessed by evaluating both the electrophysiological response (i.e., the whole-cell Na⁺ and K⁺ currents and the firing of action potentials) and also the expression of the VAChaT by immunostaining techniques. While the expression of the VAChaT was confirmed on motoneurons cultured on the fibrous scaffolds, the electrophysiological responses indicated Na⁺ and K⁺ currents with lower amplitude and slower action potentials when compared to the response recorded from spinal cord motoneurons cultured on Poly-DL-Ornithine/Laminin- and plasma-polymerized PPy-coated coverslips.Results:From a morphological viewpoint, motoneurons cultured on PLA and PPy-coated PLA scaffolds did not show the development of dendritic and/or axonal processes, which were satisfactorily observed in the bidimensional cultures.Conclusion:We hypothesize that the apparently limited development of dendritic and/or axonal processes could produce a deleterious effect on the electrophysiological response of the cells, which might be due to the limited growth surface available in the fibrous scaffolds and/or to an undesired effect of the purification process.Key Words: Electrophysiology, Pyrrol, Scaffolds     

Potentially Beneficial Effects on Healthy Aging by Supplementation of the EPA-Rich Microalgae Phaeodactylum tricornutum or Its Supernatant—A Randomized Controlled Pilot Trial in Elderly Individuals

Dietary supplements that promote healthy aging are mostly warranted in an aging society. Because of age-related risks, anti-inflammatory and anti-oxidative agents such as microalgae are potential candidates for intervention. In a randomized controlled trial, we tested Phaeodactylum tricornutum (PT), a microalgae rich in eicosapentaenoic acid (EPA), carotenoids, vitamins, and β-glucans, cultured in bioreactors. In this pilot trial, 19 healthy elderly received supplements for two weeks based on either the whole PT (A), the β-1,3-glucan-rich PT supernatant (SupB), the combination thereof (A+SupB), or a Comparator product (Comp). The primary outcome variable plasma interleukin-6 was reduced after treatment with A+SupB compared to the Comp group (p = 0.04). The mobility parameters 5 s sit-to-stand test (p = 0.04 in the A group) and by trend gait speed (p = 0.08 in the A+SupB diet) were improved compared to Comp. No treatment effects were observed for fatty acids, compared to Comp but omega-6 to -3 fatty acid ratio (p = 0.006) and arachidonic acid/EPA ratio (p = 0.006) were reduced within group A+SupB. Further, the SupB study product reduced faecal zonulin (p = 0.03) compared to the Comp. The data revealed an anti-inflammatory and potentially anti-oxidative effect of particular PT preparations, suggesting that they might be suitable for effects in healthy elderly.     

The effect of some pre-treatments on proteolysis during the ensiling of herbage

Two experiments were carried out to examine the nitrogenous changes occurring in herbage during harvesting and ensiling. In the first, ryegrass-clover was wilted rapidly in the laboratory (6 h) and in the field under good (48 h) and poor (48 h and 144 h) weather conditions. Protein breakdown and ammonia formation were negligible in herbage wilted rapidly and it was only when the crop was exposed to a prolonged wilt in humid conditions that appreciable proteolysis occurred. In the second experiment ryegrass-clover was ensiled in laboratory silos after treatment with varying levels of formic and sulphuric acids. An additional treatment included herbage inoculated with a mixture of lactic acid bacteria and glucose. The silos were opened after 4 and 50 d and samples were analysed for protein-N, ammonia-N, water-soluble carbohydrates and organic acids. There was a high negative correlation between level of addition of either acid and the degree of proteolysis and deamination. Even at the highest levels of formic acid (7·7 g per kg) and sulphuric acid (4·0 g per kg) additions, however, about 45% of the original herbage protein was degraded after 50 d in the silo. The inoculum treatment was also effective in reducing proteolysis, the effect after 50 d being comparable with formic acid applied at a rate of 4·1 g per kg.     

The digestibility of diets containing processed dried lucerne by sheep and cows

A series of trials was conducted to compare the digestibility of organic matter in castrated male sheep and non-lactating and lactating cows given diets containing lucerne cobs. Similar digestibility coefficients were determined when sheep and non-lactating cows were given hay and lucerne cobs, but lactating cows digested diets of hay, lucerne cobs and concentrates less well than sheep. It is concluded that if sheep are used in digestibility trials with diets containing processed lucerne and concentrates intended for milking cows, appreciable errors of prediction of digestibility of organic matter may arise.