Fluvoxamine inhibits some inflammatory genes expression in LPS/stimulated human endothelial cells, U937 macrophages, and carrageenan-induced paw edema in rat

Abstract

Objectives: Fluvoxamine is a well-known selective serotonin reuptake inhibitor (SSRI); Despite its anti-inflammatory effect, little is known about the precise mechanisms involved. In our previous work, we found that IP administration of fluvoxamine produced a noticeable anti-inflammatory effect in carrageenan-induced paw edema in rats. In this study, we aimed to evaluate the effect of fluvoxamine on the expression of some inflammatory genes like intercellular adhesion molecule (ICAM₁), vascular cell adhesion molecule (VCAM₁), cyclooxygenases2 (COX₂), and inducible nitric oxide synthase (iNOS).

Materials and methods: An in vitro model of LPS stimulated human endothelial cells and U937 macrophages were used. Cells were pretreated with various concentrations of fluvoxamine, from 10^-8 M to 10^-6 M. For in vivo model, fluvoxamine was administered IP at doses of 25 and 50 mg/kg^-1 , before injection of carrageenan. At the end of experiment, the expression of mentioned genes were measured by quantitative real time (RT)-PCR in cells and in paw edema in rat.

Results: The expression of ICAM₁, VCAM₁, COX₂, and iNOS was significantly decreased by fluvoxamine in endothelial cells, macrophages, and in rat carrageenan-induced paw edema. Our finding also confirmed that IP injection of fluvoxamine inhibits carrageenan-induced inflammation in rat paw edema.

Conclusion: The results of present study provide further evidence for the anti-inflammatory effect of fluvoxamine. This effect appears to be mediated by down regulation of inflammatory genes. Further studies are needed to evaluate the complex cellular and molecular mechanisms of immunomodulatory effect of fluvoxamine.

Keywords: COX2; Fluvoxamine; ICAM1; INOS; Inflammation; VCAM1.

Figure 1

Effects of fluvoxamine and LPS on cell viability of HUVECS and U937 macrophages. Cells were treated with increasing amounts of fluvoxamine (10^-8 M to 10^-6 M) and LPS (1 μg/ml) for 24 hr. Values are expressed as Mean ± SEM of three independent experiments

Figure 2

Effect of fluvoxamine on LPS-induced endothelial cells expression of ICAM₁, VCAM₁, COX₂, and iNOS. Cells were pretreated with the indicated amounts of fluvoxamine for 1 hr, and then activated with LPS (1 µg/ml). After 6 hr, RNA was purified from cells and transcription of VCAM₁ and ICAM₁ (a), and COX₂ and iNOS (b) was determined by quantitative RT-PCR. The mRNA expression data were normalized to the 18srRNA signal. Fold changes relative to control are presented as Mean±SEM. *P<0.05, **P<0.01, and *** P<0.001 compared with LPS alone treated group

Figure 3

Effect of fluvoxamine on LPS-induced U937 macrophages expression of iNOS and COX₂. Cells were pretreated with the indicated amounts of fluvoxamine for 1 hr, and then activated with LPS (1 µg/ml). After 6 hr, RNA was purified from cells and transcription of COX₂ and iNOS was determined by quantitative RT-PCR. The mRNA expression data were normalized to the 18srRNA signal. Fold changes relative to control are presented as Mean±SEM. *P<0.05, *** P<0.001, compared with LPS alone treated group

Figure 4

Effect of IP administration of fluvoxamine on carrageenan-induced paw edema in rat. Fluvoxamine or the vehicle was administrated 30 min prior to the carrageenan (1%) injection and rats were evaluated for paw edema at 4 hr post-carrageenan. A group of animals received dexamethasone (1 mg/kg) as a reference drug. Changes in the paw volume are presented as Mean±SD (n = 6, *** P<0.001 compared with control group). Dex: dexamethasone

Figure 5

Effect of fluvoxamine on the gene expression of ICAM₁, VCAM₁ (a), iNOS, and COX₂ (B) in carrageenan-induced paw edema in rats. Fluvoxamine at doses of 25 and 50 mg/kg was given 30 min before subplantar injection of carrageenan (1%). Control group received only vehicle. A group of animals that was pretreated with dexamethasone (1 mg/kg) was used as the positive control. RNA was purified from inflamed frozen paw and transcription of ICAM₁, VCAM₁, iNOS, and COX₂ was determined by quantitative RT-PCR. The mRNA expression data were normalized to the 18srRNA signal. Fold changes relative to control are presented as Mean±SEM. *P<0.05, **P<0.01, and *** P<0.001 compared with only carrageenan received group.