Validation and additional support for an experimental animal model of fibromyalgia.

OBJECTIVES: In the current study, we have evaluated the intermittent cold stress (ICS) induction in mice, in order to validate and optimize its utility as a fibromyalgia-like model. METHODS: Twenty-four mice of 5-week old, female Swiss, weighing 18-22 g were used for the experiments. These mice were divided into three groups of eight animals per group [health control group (control), ICS group (ICS), and Gabapentin group (GBP)]. When in-vivo tests were completed, we proceeded to isolation and culture of peritoneal macrophages in order to determine the effects of the ICS on the release of proinflammatory mediators. RESULTS: The results showed that this model is suitable to induce mechanical allodynia, thermal allodynia, and hyperalgesia. It is also able to reproduce behavioral changes related to cognitive disturbances, anxiety, and depression. Besides, ICS model might increase the inflammatory response in LPS-macrophages stimulated from stressed mice. CONCLUSIONS: Our results show that ICS is a useful animal model to assess hypothesis about underlying mechanisms involved in the development of fibromyalgia as well as to evaluate possible future therapies.

The sterols isolated from Evening Primrose oil modulate the release of proinflammatory mediators.

Evening Primrose oil is a natural product extracted by cold-pressed from Oenothera biennis L. seeds. The unsaponifiable matter of this oil is an important source of interesting minor compounds, like long-chain fatty alcohols, sterols and tocopherols. In the present study, sterols were isolated from the unsaponifiable matter of Evening Primrose oil, and the composition was identified and quantified by GC and GC-MS. The major components of sterols fraction were ß-Sitosterol and campesterol. We investigated the ability of sterols from Evening Primrose oil to inhibit the release of different proinflammatory mediators in vitro by murine peritoneal macrophages stimulated with lipopolysaccharide. Sterols significantly and dose-dependently decreased nitric oxide production. Western blot analysis showed that nitric oxide reduction was a consequence of the inhibition of inducible nitric oxide synthetase expression. Sterols also reduced tumor necrosis factor-α, interleukine 1ß and tromboxane B2. However, sterols did not reduce prostaglandin E2. The reduction of eicosanoid release was related to the inhibition of cyclooxygenase-2 expression. These results showed that sterols may have a protective effect on some mediators involved in inflammatory damage development, suggesting its potential value as a putative functional component of Evening Primrose oil.