Non invasive jacketed telemetry in socially-housed rats for a combined assessment of respiratory system, electrocardiogram and activity using the DECRO system.

Respiratory and cardiovascular systems are among the vital organ systems that should be studied in safety pharmacology core battery test. Non-invasive jacketed external telemetry technology that enables concomitant monitoring of both systems has been available and used widely for non-rodent species. Recently, the DECRO system, a miniaturized technology system in line with the "3Rs" principles, has been developed to provide a similar approach in rats. However, data to evaluate this system in socially-housed rats is lacking. Therefore, the objectives of this study were to determine the tolerability and the material integrity of this novel solution in pair-housed rats in two conditions: i) in a single session of 22 h simulating a stand-alone safety pharmacology study design, and ii) in three repeated sessions of 22 h each, simulating the inclusion of safety pharmacology endpoints in a 1-month toxicology study. In both conditions, the GABAB receptor agonist baclofen was used as a reference compound inducing cardiorespiratory changes. Our results provided evidence that this novel solution was well tolerated, the material was resistant to deterioration and that it allowed the accurate recording, in a non-invasive manner, of cardiorespiratory parameters and activity level in freely moving, pair-housed rats in the above two conditions. In addition, the expected respiratory depressant effects of baclofen were recorded. These results pave the way for considering this novel solution as an enhanced approach for nonclinical safety assessment in rats.

Characterization of a rat model of moderate liver dysfunction based on alpha-naphthylisothiocyanate-induced cholestasis.

Plasma amino acid level changes occur in mild, moderate and severe stages of liver injury in human patients. In animal models, however, data are mainly restricted to severe liver injury models in rats. Here we present the characterization of a rat model of moderate liver dysfunction secondary to alpha-napthylisothiocyanate (ANIT)-induced cholestasis. Rats treated with 30 mg/kg/day ANIT for 3 weeks exhibited a time-dependent increase in plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST) and bilirubin levels and a decrease in albumin concentration. According to a liver dysfunction evaluation based on the human Child-Pugh-Score, animals developed a moderate liver dysfunction in the first two weeks of ANIT treatment, while only a mild dysfunction was observed at the end of week 3 despite ongoing ANIT administration. Univariate analysis of branched-chain amino acid plasma levels indicated that reduced levels of branched chain amino acids were associated with the ANIT treatment. These data may set the stage for further research of amino acid disturbances and requirements in non-severe cholestasis.

Effects of Adjuvant Systems on the cardiovascular and respiratory functions in telemetered conscious dogs and anaesthetised rats.

Adjuvants Systems (AS) containing immunostimulant combinations are used in human vaccines. Safety pharmacology studies evaluated the cardiorespiratory effects of AS in conscious telemetered dogs and in anaesthetised rats. Sixteen telemetered beagle dogs (4/group) received intramuscular injections of saline at Day 0, and one clinical dose of AS01, AS03, AS04 or AS15 at Day 7 (7× the equivalent human dose on a bodyweight basis). Bodyweights were measured through Day 14 and cardiorespiratory parameters and body temperature through 72 h post-treatment. Anaesthetised rats (4/group) received one intravenous injection of AS01, AS03 or AS15 at 1 mL/kg bodyweight (140× the equivalent human dosages), or saline. Cardiorespiratory parameters were measured for 120 min post-dose. In dogs, food consumption and mean bodyweight decreased with AS03, and mean body temperature slightly increased with AS01, AS03 and AS15, but were not considered to be adverse. Cardiovascular effects (a slight, reversible increase in mean heart rate and shortened mean RR/PR/QT-intervals) were observed with AS15. No relevant clinical effects or effects on QRS-complex/QTc-interval durations, arterial pressure or respiratory parameters were observed. In rats, there were no consistent treatment-related effects. Collectively, this suggests that AS01, AS03, AS04 and AS15 are not associated with potentially deleterious effects on ventricular repolarisation, atrio/intra-ventricular conductivities or respiratory functions.