Harm–benefit analysis – what is the added value?:A review of alternative strategies for weighing harms and benefits as part of the assessment of animal research

Animal experiments are widely required to comply with the 3Rs, to minimise harm to the animals and to serve certain purposes in order to be ethically acceptable. Recently, however, there has been a drift towards adding a so-called harm-benefit analysis as an additional requirement in assessing experiments. According to this, an experiment should only be allowed if there is a positive balance when the expected harm is weighed against the expected benefits. This paper aims to assess the added value of this requirement. Two models, the discourse model and the metric model, are presented. According to the former, the weighing of harms and benefits must be conducted by a committee in which different stakeholders engage in a dialogue. Research into how this works in practice, however, shows that in the absence of an explicit and clearly defined methodology, there are issues about transparency, consistency and fairness. According to the metric model, on the other hand, several dimensions of harms and benefits are defined beforehand and integrated in an explicit weighing scheme. This model, however, has the problem that it makes no real room for ethical deliberation of the sort committees undertake, and it has therefore been criticised for being too technocratic. Also, it is unclear who is to be held accountable for built-in ethical assumptions. Ultimately, we argue that the two models are not mutually exclusive and may be combined to make the most of their advantages while reducing the disadvantages of how harm-benefit analysis in typically undertaken

An improved method for constructing and selectively silanizing double-barreled, neutral liquid-carrier, ion-selective microelectrodes

We describe an improved, efficient and reliable method for the vapour-phase silanization of multi-barreled, ion-selective microelectrodes of which the silanized barrel(s) are to be filled with neutral liquid ion-exchanger (LIX). The technique employs a metal manifold to exclusively and simultaneously deliver dimethyldichlorosilane to only the ion-selective barrels of several multi-barreled microelectrodes. Compared to previously published methods the technique requires fewer procedural steps, less handling of individual microelectrodes, improved reproducibility of silanization of the selected microelectrode barrels and employs standard borosilicate tubing rather than the less-conventional theta-type glass. The electrodes remain stable for up to 3 weeks after the silanization procedure. The efficacy of a double-barreled electrode containing a proton ionophore in the ion-selective barrel is demonstrated in situ in the leaf apoplasm of pea (Pisum) and sunflower (Helianthus). Individual leaves were penetrated to depth of ~150 μm through the abaxial surface. Microelectrode readings remained stable after multiple impalements without the need for a stabilizing PVC matrix

Behaviour, stress and welfare of Sprague Dawley rats (Rattus norvegicus) on diet board feeding for 24 months

Abstract Diet board (DB) feeding aims to reduce the health hazards associated with ad libitum (AL) feeding. Rats have to gnaw wood to detach food from the DB, reducing their food consumption. We studied the welfare effects of DB by measuring faecal corticosterone metabolites (FCM), elevated plus-maze (EPM) behaviour and cage behaviour. In this two-year experiment, 147 group housed (n = 3) Hsd:Sprague Dawley® male and female rats were subjected to DB or AL feeding. DB feeding in females elevated FCMs and increased eating observations by 85%. The DB males were observed eating 30% more often and resting 4.2% less than their AL counterparts. The DB rats of both sexes had 19% increased cage exploration during daytime and 20% reduced grooming during night-time compared to the AL rats. The increased FCMs may indicate slight stress in DB females. The EPM results indicate there was no anxiety due to DB feeding at six months. The cage behaviour could point to mild chronic stress in DB rats, but the lack of effect on escape-related behaviour and agonism suggests that there were no substantial welfare problems. DB feeding did not seem to disturb the circadian rhythm. The smaller food requirements of DB females meant they had to sacrifice less time than males gnawing at the DB to satisfy their appetite

Mice with targeted Slc4a10 gene disruption have small brain ventricles and show reduced neuronal excitability

Members of the SLC4 bicarbonate transporter family are involved in solute transport and pH homeostasis. Here we report that disrupting the Slc4a10 gene, which encodes the Na+-coupled Cl−–HCO3− exchanger Slc4a10 (NCBE), drastically reduces brain ventricle volume and protects against fatal epileptic seizures in mice. In choroid plexus epithelial cells, Slc4a10 localizes to the basolateral membrane. These cells displayed a diminished recovery from an acid load in KO mice. Slc4a10 also was expressed in neurons. Within the hippocampus, the Slc4a10 protein was abundant in CA3 pyramidal cells. In the CA3 area, propionate-induced intracellular acidification and attenuation of 4-aminopyridine-induced network activity were prolonged in KO mice. Our data indicate that Slc4a10 is involved in the control of neuronal pH and excitability and may contribute to the secretion of cerebrospinal fluid. Hence, Slc4a10 is a promising pharmacological target for the therapy of epilepsy or elevated intracranial pressure