RESUMO
The ovine choroid plexus (ChP) expresses the long isoform of the leptin receptor, which makes this structure a potential target for leptin action. In sheep, leptin concentration in plasma is higher during long days (LD) than short days (SD). This study evaluates the influence a of photoperiod on leptin impact on the gene expression of Toll-like receptor 4 (TLR4), proinflammatory cytokines (IL1B, IL6), their receptors (IL1R1, IL1R2, ILRN, IL6R, IL6ST) and inflammasome components necessary for pro-IL-1ß activation (NLRP3, PYCARD, CASP1), chemokine (CCL2), leptin receptor isoforms (LEPRa, LEPRb) and a suppressor of cytokine signalling (SOCS3) in the ChP of ewes treated or not with lipopolysaccharide (LPS). Studies were conducted on adult female sheep divided into four groups (n = 6 in each): control, leptin (20 µg/kg), LPS (400 ng/kg), and LPS and leptin injected under SD and LD photoperiods. The leptin alone did not affect the gene expression but in co-treatment with LPS increased (p < 0.05) IL1B but only during SD, and SOCS3, IL1R2, IL1RN, IL6ST and CCL2 only during LD, and decreased (p < 0.05) the IL1R1 expression only during SD photoperiod. This indicates that the immunomodulatory action of leptin on the ChP is manifested only under the LPS challenge and is photoperiodically dependent.
Assuntos
Plexo Corióideo/metabolismo , Inflamassomos/metabolismo , Leptina/sangue , Fotoperíodo , Animais , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Plexo Corióideo/efeitos dos fármacos , Feminino , Inflamassomos/genética , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Lipopolissacarídeos/toxicidade , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Interleucina/genética , Receptores de Interleucina/metabolismo , Receptores para Leptina/genética , Receptores para Leptina/metabolismo , Ovinos , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismoRESUMO
There have been many methods proposed to induce molting. Some worked very well in practice, but others were detrimental to the health and welfare of the hens. The most effective methods use some level of feed restriction and daylength manipulation to reduce body weight (Hansen, 1966; Ruszler, 1974, 1984, 1996; Swanson and Bell, 1974; Brake and Carey, 1983). Weight reduction is necessary for rest and rejuvenation of body tissues. Other methods evaluated incorporated dietary imbalances using either zinc, iodine, or sodium. Pharmaceuticals have been used but have not been cost effective. In recent years there have been those who question whether molting techniques are humane. Therefore, interest has been heightened in alternate methods to induce molting. Research reported to date has been inadequate to accurately determine which methods of induced molting are the least stressful, if they in fact, cause any more stress than that experienced by the hen during a natural molt. The three or four most highly refined methods being used commercially are not generally detrimental to the health and welfare of today's laying hen, provided that they are managed in accordance with proper husbandry practices.