Suppression of type II collagen-induced arthritis by N-acetyl-L-cysteine in mice

1. The antiarthritic and anti-inflammatory efficacy of N-acetyl-L-cysteine (NAC) was tested in male DBA/1 hybrid mice suffering from type II collagen-induced arthritis. Parameters including the arthritis index and the phagocytic responses recorded by chemiluminescence in unseparated blood were used for the assessment of disease activity. 2. Mice were immunized by subdermal injection of bovine type II collagen in Freund's complete adjuvant. The treatment with NAC started at day 42 after immunization and was continued over a period of six weeks: in doses ranging up to 50 mg/kg, a dose-dependent suppression of arthritis was noted; between 50 and 200 mg/kg, the inhibition curve had a plateau [ED50 = 50 mg/(kg x day)]. 3. The arthritis index correlated positively with the generation of chemiluminescence by reactive oxygen species (ROS) produced in neutrophils and monocytes activated by 12-O-tetradecanoylphorbol 13-acetate. 4. After treatment with 100 mg/kg of NAC from day 42 after immunization over a period of six weeks, the ROS production was reduced to levels occurring in whole blood of healthy animals. 5. It is concluded that low-molecular-weight antioxidants such as NAC may be adequate for controlling oxidative stress-derived damage in rheumatic diseases by modulation of ROS-dependent signal transduction pathways.

Synergistic effects of thalidomide and poly (ADP-ribose) polymerase inhibition on type II collagen-induced arthritis in mice

The present study investigates synergistic effects of the TNF-alpha inhibitor thalidomide and the poly(ADP-ribose) polymerase (PARP)-inhibitor nicotinic acid amide (NAA) in male DBA/1 hybird mice suffering from type II collagen-induced arthritis. Parameters including the arthritis index, chemiluminescence and anti-collagen antibody titers were used for the assessment of disease activity: The disease courses demonstrated clearly an inhibitory effect of thalidomide. NAA inhibited established collagen arthritis in a dose-dependent manner. The combined application of thalidomide and NAA caused a powerful synergistic inhibition of arthritis. Furthermore, thalidomide and NAA were tested ex vivo for their inhibition of the NADPH oxidase-dependent generation of reactive oxygen species by activated neutrophils and monocytes in unseparated human blood. Our data show that type II collagen-induced arthritis can be suppressed by the simultaneous inhibition of TNF-alpha, PARP, and NADPH oxidase.

Exacerbation of acetaminophen hepatotoxicity by thalidomide and protection by nicotinic acid amide

1. The effects of racemic thalidomide (D[+]/L[-] alpha-phthalimido-glutarimide) on acetaminophen (AAP)-induced hepatitis were tested in male NMRI mice (n = 133) and quantified as serum activities of glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT). 2. A 2.1-fold increase of GOT and a 1.9-fold increase of GPT activities (P < 0.001) were observed in mice treated perorally with 500 mg/kg of AAP plus 150 mg/kg of thalidomide (Thal). In the absence of AAP, Thal did not display any detectable hepatotoxic effects. 3. The Thal-induced exacerbation of AAP hepatotoxicity was completely inhibited by nicotinic acid amide, a selective inhibitor of poly(ADP-ribose) polymerase (PARP) (P < 0.0001), suggesting a possible influence of Thal on the hepatic metabolism of NAD-adenoribosylation. 4. We see the main application of nicotinic acid amide as for the combinational use in pharmaceutical preparations of AAP in order to avoid hepatic damage in patients treated with AAP and Thal.

[Embryotoxic interactions between a hydrolysis product of thalidomide and the surfactant Tween 20 in mice]

N,N-phthaloyl-L-glutamic acid (NPLG), a hydrolysis product of thalidomide, and the surfactant Tween 20 were co-administered intraperitoneally to pregnant NMRI mice on days 9 and 8 2/3 p.c. at doses where the hydrolysis product as well as the surfactant alone induce minimal embryotoxicity. The combined substances (350 mg/kg NPLG + 1.0 ml/kg Tween 20) caused a potentiative teratogenic and an additive embryolethal response. Enhancement of the amount of Tween 20 in the combinations to 2.5 ml/kg led to the same potentiative teratogenic and, in addition, potentiative embryolethal response. Distribution studies using 14C-NPLG showed a strongly increased NPLG content in the maternal plasma under the influence of 2.5 ml/kg Tween 20 but not after co-administration with 1.0 ml/kg Tween 20. The malformations obtained were of the same type in all groups and mostly located in the vertebrae and ribs. These axial and paraxial defects were frequently more severe and included more affected elements after application of the combined than of the single substances. Extension of our experiments with the combined substances to treatment days 8 1/2 and 9 1/2 p.c. revealed that the first affected segment shifts in caudal direction depending on an increasing embryonal age at treatment. Limb malformations occurred at a low frequency; most of them were of the same type as described in cases of human thalidomide embryopathy.

Teratologic studies on the Himalayan rabbit: new aspects of thalidomide-induced teratogenesis

The aim of our study was to determine the period of maximum sensitivity for the induction of characteristic malformations with thalidomide (TH) in Himalayan rabbits. TH was administered orally in different doses (50, 100, 150 and 200 mg/kg) four times at 24-h intervals starting at 192 h of gestation. The malformations affected various organs: renal defects (dysplasia) and limb anomalies (dysmelia)--which had never occurred spontaneously in this strain--appeared as dose-dependent effects of the drug. By administering single doses of TH (200 and 300 mg/kg body wt) between hours 192 and 264 of gestation, we discovered the different periods of maximum sensitivity for induction of renal dysplasia (clearly prior to the 220th h of gestation) and dysmelia (between hours 230 and 240 of gestation). The types of limb malformations that we observed in the rabbit were identical to those produced in man following the intake of TH. Three doses of TH (300 mg/kg each) given between hours 222 and 228 of gestation produced characteristic limb malformations in 9 of 11 litters treated. These results make it possible to conduct in vivo experiments on a readily available laboratory animal with minor drug exposure of the gravid dam and under avoidance of toxic side effects.

[Mass spectra of 1-dimethylaminonaphthalene-5-sulfonyl derivatives of some metabolites of catecholamines]

The mass spectra of 1-dimethylaminonaphthalene-5-sulfonyl derivatives of the phenolic aldehydes 4-hydroxybenzaldehyde, 3-hydroxybenzaldehyde, vanillin, isovanillin and protocatechualdehyde were determined and discussed.