Unrelieved Pain and Distress in Animals: An Analysis of USDA Data on Experimental Procedures

Efficacy of a Combination of N-Palmitoylethanolamide, Beta-Caryophyllene, Carnosic Acid, and Myrrh Extract on Chronic Neuropathic Pain: A Preclinical Study

Neuropathic pain (NP) is a common public health problem that poses a major challenge to basic scientists and health-care providers. NP is a complex problem with an unclear etiology and an often-inadequate response to current medications. Despite the high number of drugs available, their limited pharmacological efficacy and side effects hamper their chronic use. Thus, the search for novel treatments is a priority. In addition to pharmaceuticals, natural extracts and food supplements are often used to help treating patients with NP. One such supplement is Noxiall^®, a commercially available combination of N-Palmitoylethanolamide (PEA), beta-caryophyllene; carnosic acid and myrrh. Here, we compare the efficacy of Noxiall^® to that of the medications gabapentin and pregabalin in the NP model of chronic constriction injury (CCI) using sciatic nerve ligation in mouse. Following CCI, mice developed a significant increase in mechanical allodynia and thermal hyperalgesia. Results showed that administration of either Noxiall^®, pregabalin, or gabapentin significantly attenuated mechanical allodynia. The magnitude of the Noxiall^® effect was comparable to that of gabapentin or pregabalin. In addition, co-administration of non-effective doses of pregabalin and Noxiall^® resulted in a significant decrease in NP, suggesting an additive efficacy. Noxiall^® was efficacious also in reducing CCI-induced thermal hyperalgesia. These findings support the rationale of using natural remedies in conjunction with classical pharmacological agents to treat chronic NP.

Classifying the severity of scientific animal use: a review of international systems

Severity classification systems (ie pain scales, categories of invasiveness, degrees of severity etc) are used to classify the adverse effects experienced by animals used for scientific purposes. Currently, eleven countries use severity classification systems. These systems have developed in various ways, depending on each country's process for overseeing the use of animals in science, as well as the particular aspects emphasised by those individuals who have championed their implementation. Severity classification serves four main purposes: as a tool to assist animal ethics committees in ethical review; education of animal users about concepts for humane animal experimentation; provision of data to inform the public about scientific animal use; and provision of data to inform national policies. At a time when the newly accepted European Union Directive will make the reporting of severity data mandatory, we review the characteristics of international severity classification systems and how they have evolved; analyse the effectiveness of some systems; and identify emerging challenges for severity classification.

Animal carcinogenicity studies: 1. Poor human predictivity

The regulation of human exposure to potentially carcinogenic chemicals constitutes society's most important use of animal carcinogenicity data. Environmental contaminants of greatest concern within the USA are listed in the Environmental Protection Agency's (EPA's) Integrated Risk Information System (IRIS) chemicals database. However, of the 160 IRIS chemicals lacking even limited human exposure data but possessing animal data that had received a human carcinogenicity assessment by 1 January 2004, we found that in most cases (58.1%; 93/160), the EPA considered animal carcinogenicity data inadequate to support a classification of probable human carcinogen or non-carcinogen. For the 128 chemicals with human or animal data also assessed by the World Health Organisation's International Agency for Research on Cancer (IARC), human carcinogenicity classifications were compatible with EPA classifications only for those 17 having at least limited human data (p = 0.5896). For those 111 primarily reliant on animal data, the EPA was much more likely than the IARC to assign carcinogenicity classifications indicative of greater human risk (p < 0.0001). The IARC is a leading international authority on carcinogenicity assessments, and its significantly different human carcinogenicity classifications of identical chemicals indicate that: 1) in the absence of significant human data, the EPA is over-reliant on animal carcinogenicity data; 2) as a result, the EPA tends to over-predict carcinogenic risk; and 3) the true predictivity for human carcinogenicity of animal data is even poorer than is indicated by EPA figures alone. The EPA policy of erroneously assuming that tumours in animals are indicative of human carcinogenicity is implicated as a primary cause of these errors.

Possibilities for refinement and reduction: future improvements within regulatory testing

Approaches and challenges to refining and reducing animal use in regulatory testing are reviewed. Regulatory testing accounts for the majority of animals reported in the most painful and/or distressful categories in the United States and Canada. Refinements in testing, including the use of humane endpoints, are of increasing concern. Traditional approaches to reduction (e.g., improving experimental design) are being supplemented with complementary approaches, such as the use of tier testing to eliminate some chemicals prior to in vivo testing. Technological advances in telemetry and noninvasive techniques will help decrease either the demand for animals in testing or animal suffering. Further decreases in animal use will stem from international harmonization and coordination of testing programs. Progress in refinement and reduction faces a variety of broad challenges, including limited funding for research. In the specific area of refinement, a key challenge is the issue of distress (as distinct from pain). In the area of reduction, the practice of using unjustifiably high numbers of animals from small species (e.g., rodents) should be challenged. One case study of the use of carbon dioxide as a euthanasia agent illustrates the need for further analysis and research. Notwithstanding the complexities and challenges, the potential for refinement and reduction in regulatory testing is encouraging.

Animal usage in vaccine development and production: maximising results while minimizing use

The Third International Symposium on Advancing Science and Elimination of the Use of Laboratory Animals for Development and Control of Vaccines and Hormones, organized by the National Institute of Public Health and the Environment (RIVM, The Netherlands) under the auspices of the International Association for Biologicals (IABS), was held in Utrecht, The Netherlands, 12-14 November 2001.