The OARSI histopathology initiative – recommendations for histological assessments of osteoarthritis in the rat

SummaryObjectiveDuring the development of disease-modifying osteoarthritis (OA) drugs, rat models of OA are frequently used for a first assessment of in vivo efficacy. The most efficacious compound in the rat model may then be tested in a larger animal model before entering human trials. The aim of this study was to describe a histologic scoring system for use in different models of OA in rats that allows standardization and comparison of results obtained by different investigators.MethodsThe experience of the authors with current scoring systems and the range of lesions observed in rat and human OA studies were considered in recommending this common paradigm for rat histologic scoring. Considerations were made for reproducibility and ease of use for new scorers. Additional scoring paradigms may be employed to further identify specific effects of some disease-modifying drugs.ResultsAlthough the described scoring system is more complex than the modified Mankin scores, which are recommended for some other species, the reliability study showed that it is easily understood and can be reproducibly used, even by inexperienced scorers.ConclusionsThe scoring paradigm described here has been found to be sufficiently sensitive to discriminate between treatments and to have high reproducibility. Therefore we recommend its use for evaluation of different rat OA models as well as assessment of disease-modifying effects of treatments in these models

Analysis of Babesia bovis infection-induced gene expression changes in larvae from the cattle tick, Rhipicephalus (Boophilus) microplus

Background: Cattle babesiosis is a tick-borne disease of cattle that has severe economic impact on cattle producers throughout the world's tropical and subtropical countries. The most severe form of the disease is caused by the apicomplexan, 'Babesia bovis', and transmitted to cattle through the bite of infected cattle ticks of the genus 'Rhipicephalus', with the most prevalent species being 'Rhipicephalus (Boophilus) microplus'. We studied the reaction of the 'R. microplus' larval transcriptome in response to infection by 'B. bovis'. Methods: Total RNA was isolated for both uninfected and 'Babesia bovis'-infected larval samples. Subtracted libraries were prepared by subtracting the 'B. bovis'-infected material with the uninfected material, thus enriching for expressed genes in the 'B. bovis'-infected sample. Expressed sequence tags from the subtracted library were generated, assembled, and sequenced. To complement the subtracted library method, differential transcript expression between samples was also measured using custom high-density micro arrays. The micro array probes were fabricated using oligonucleotides derived from the Bmi Gene Index database (Version 2). Array results were verified for three target genes by real-time PCR. Results: Ticks were allowed to feed on a 'B. bovis'-infected splenectomized calf and on an uninfected control calf. RNA was purified in duplicate from whole larvae and subtracted DNA libraries were synthesized from 'Babesia'-infected larval RNA, subtracting with the corresponding uninfected larval RNA. One thousand ESTs were sequenced from the larval library and the transcripts were annotated. We used a 'R. microplus' micro array designed from a 'R. microplus' gene index, BmiGI Version 2, to look for changes in gene expression that were associated with infection of 'R. microplus' larvae. We found 24 transcripts were expressed at a statistically significant higher level in ticks feeding upon a 'B. bovis'-infected calf contrasted to ticks feeding on an uninfected calf. Six transcripts were expressed at a statistically significant lower level in ticks feeding upon a 'B. bovis'-infected calf contrasted to ticks feeding on an uninfected calf

The ovarian transcriptome of the cattle tick, Rhipicephalus (Boophilus) microplus, feeding upon a bovine host infected with Babesia bovis

Cattle babesiosis is a tick-borne disease of cattle with the most severe form of the disease caused by the apicomplexan, Babesia bovis. Babesiosis is transmitted to cattle through the bite of infected cattle ticks of the genus Rhipicephalus. The most prevalent species is Rhipicephalus (Boophilus) microplus, which is distributed throughout the tropical and subtropical countries of the world. The transmission of B. bovis is transovarian and a previous study of the R. microplus ovarian proteome identified several R. microplus proteins that were differentially expressed in response to infection. Through various approaches, we studied the reaction of the R. microplus ovarian transcriptome in response to infection by B. bovis