Low-grade chronic inflammation induces behavioral stereotypy in rats

Abstract

Schizophrenia is known to be associated with metabolic disturbances including diabetes mellitus, obesity and cardiovascular diseases. A growing body of evidence has suggested abnormal cytokine levels in schizophrenia. In the present study, we explored the effects of low-grade chronic inflammation on behavioral stereotypy in a rat model of non-alcoholic fatty liver disease (NAFLD). In order to induce NAFLD, rats were fed with either water enriched with 30 % fructose or plain tap water for 8 weeks. Following feeding period, behavioral stereotypy was evaluated with apomorphine-induced stereotypy test. Also, levels of tumor necrosis factor alpha (TNF-α), interleukin 2 (IL-2) and nuclear factor kappa B (NF-κB) in the liver and brain tissues were assessed biochemically. Brain homovanilic acid (HVA) was measured to evaluate the dopamine turnover. NAFLD rats showed significantly higher stereotypy score compared to controls (p = 0.016). TNF-α, IL-2, and NF-κB levels were significantly increased in NAFLD rats compared to control group. Brain HVA levels were elevated in NAFLD rats as well (p = 0.008). Moreover, NAFLD group prompted a considerable increase in brain IL-2 immunoexpression (p = 0.005). In conclusion, the present study demonstrates that low-grade chronic inflammation such as NAFLD may enhance apomorphine-induced stereotypic behavior via increasing dopaminergic activity in rats.

Neurobehavioral effects of long‐term maternal fructose intake in rat offspring

“…Apomorphine‐induced stereotypy is a convenient method used in vivo tests for evaluating the effects of dopamine agonists or antagonists as well as for the assessment of dopaminergic activity (Erbaş et al, 2015). Apomorphine (1.5 mg/kg subcutaneously) was administered to all animals.…”

“…In a previous study, we have reported that long‐term fructose‐received adult rats revealed significantly higher stereotypy score, elevated levels of brain and liver cytokines and brain dopaminergic activity than those of their normal controls (Erbaş et al, 2015). In the present study, we aimed to investigate the neurodevelopmental effects of long‐term maternal metabolic deterioration on offspring using a rat model of fructose‐induced metabolic syndrome.…”

Effect of Advanced Glycation End-Products and Excessive Calorie Intake on Diet-Induced Chronic Low-Grade Inflammation Biomarkers in Murine Models

“…Adipose tissue 3-fold change (↑) (mRNA) [37] BAL No change (→) (Protein) [42] Brain Control: 0.2 ng/mg Affected: 0.7 ng/mg (↑) (Protein) [36] Kidney 10-fold change (↑) (mRNA) [43] Liver 3-fold change (↑) (mRNA) [38] No change (→) (mRNA) [37] Control: 0.7 ng/mg Affected: 1 ng/mg (↑) (Protein) [36] Myocardium 2-fold change (↑) (mRNA) [45] Plasma Control: 4 pg/mL Affected: 10 pg/mL (↑) (Protein) [39] No change (→) (Protein) [57] Tumor necrosis factor soluble receptor II (TNF-sRII) [36] Liver Control: 10 pg/mL (→) (Protein) [36] IκB kinase (pIKK) Peritone 4-fold change (↑) (mRNA) [46] Mechanistic target of rapamycin (mTOR) Liver Control: 3 ng/mg Affected: 6 ng/mg (↑) (Protein) [52] Protein kinase B (AKT) Adipose tissue 1.5-fold (↓) (mRNA) [41] No change (→) (Protein) [58] LPS presenting protein Despite the fact that we have not attempted to be exhaustive in this review, significant diversity can be observed among the molecular biomarkers of inflammation listed in Table 1. Cytokines and chemokines are by far the most studied molecules, and IL-6, TNF-α, and MCP-1 figure among the most studied biomarkers in dietary studies with animal models.…”

Relationship between alcoholism addiction and periodontitis. An in vivo study using drinking-in-darkness protocol in rats

“…14, 21 However, there is still much to be clarified about the molecular mechanisms that induce changes at the level of the central nervous system. A bidirectional and robust interaction between the inflammatory process and different comorbidities has been established.…”