Background and aim: High caloric diet (HCD) in diet-induced obesity (DIO) can be caused by central mechanisms regulating reward-seeking behaviour. Leptin modulates the dopamine system and vice versa. We supposed D2 dopamine receptor agonist and dopamine neurons toxin to influence weight gain and leptin level, mobility and behaviour in wild type rats (GUR) with HCD.
Materials and methods: Male rats (n=64, 183.0±14.0 g) were divided into HCD group (n=36) and standard caloric diet (SCD) (n=36). HCD and SCD rats had daily intraperitoneal injections of Bromocriptin (B) (1 mg/kg), Rotenone (R) (0.3 mg/kg), dimethyl sulfoxide (DMSO vehicle, 1 ml/kg) (n=8, respectively) during 3 months. Eight rats from both groups werent injected. Length, weight and caloric intake were recorded twice a week. Leptin levels (immunoenzyme analysis and leptin/weight ratio (L/WR)) and rodents speed (S), distance (D), open and closed arms visits and time (plus maze test) were discovered at the 1st and 3rd months. Nonparametric analysis was performed (SPSS 16.0, P<0.05).
Results: HCD rats showed similar weight gain in 1st and 3rd months compared to SCD rodents irrespective to injected agent with lowest weight gain in HCD rats received R (P<0.05). S and D had no changes in HCD group after 1 month but open arm visits significantly decreased in HCD rats injected with B (P<0.05). S reduced after 3 months in HDC rats compared to the same group after 1 month (P>0.05). Leptin and LWR decreased after 3 months of Br injections in HCD rats relative to the HCD rodents (P=0.05 and 0.005 comparatively). Leptin and LWC levels were extensively lower in Br injected HCD rats in 3 month concerning to the 1st one.
Conclusion: Long-term Bromocriptin injections prevent leptin resistance and neurotoxic Rotenone effect leads to weight gain diminishing in HCD DIO rats.
Funding: The work was supported by Belorussian republican foundation for fundamental research (grant number 20122542, 2012).
01 Oct 2015 - 03 Oct 2015