Furthermore, we showed that rats treated with Ang-(1–7) presented with diminished liver resistin expression associated with increased ACE2 expression. These results are in agreement with the data obtained in previous studies [9] and [10]. Oh et al. recently showed that captopril (ACE inhibitor) intake decreases body weight gain via Angiotensin-(1–7)
[14]. This alteration was associated with Mas receptor mRNA increased expression [14]. Additionally, a previous study with DOCA salt-induced hypertension transgenic rats, that presents an overexpression of Ang-(1–7) in the circulation, also showed an increase in heart Ang-(1–7) accompanied by a decrease in ACE mRNA expression [17]. These data support our hypothesis of a modulatory role for Ang-(1–7) in the ACE/ACE2 ratio. Another possibility is that the improved metabolic profile LBH589 by itself, with lower lipid content and enhanced Neratinib in vitro glucose metabolism, was able to increase ACE2 and decrease ACE expression. A previous report revealed that Ang II treatment increases adipocytes secretion of resistin [7].
Resistin has been also associated with the inflammatory state of chronic liver disease [25] and modulates the synthesis and secretion of key proinflammatory cytokines such as TNF-α and IL-6 [24]. The molecular mechanisms involved in the inflammatory response of resistin are still unclear, however a recent report indicated that resistin could compete with LPS for TLR4 [9]. Additionally a recent investigation reported the contribution of central resistin overexposure to induction of insulin resistance through TLR4 and activation of MAPK pathway [1]. In our study, we showed decreased TLR4 mRNA expression in liver of HFD + Ang-(1–7) rats associated with low phosphorylation GBA3 of MAPK. This fact is important once resistin-TLR4 signaling in the hypothalamus leads to the
activation of MAPK pathway promoting overall inflammation [1]. It is known that MAPK activation initiates the downstream induction of transcription factors such as NF-κB, which is an essential regulator of the expression of numerous genes involved in the function and development of the immune system and in inflammatory responses [22]. Activated NF-κB is the major regulator, facilitating the synthesis of several different injury-responsive cytokines in neurons, adipose tissue and liver [2], [22] and [24]. Previous studies showed an elevated level of NF-κB in the adipose tissue of rats with increased levels of resistin [15] and [25]. In this study, oral treatment with Ang-(1–7) reduced TNF-α and IL-6 through inhibition of NF-κB. In summary the present study showed that Ang-(1–7) oral treatment in rats fed high-fat feed prevent obesity and the decrease of several liver proinflammatory cytokines by down-regulating the resistin/TLR4/NF-κB pathway.