Beneficial metabolic effects of CB1R anti-sense oligonucleotide treatment in diet-induced obese AKR/J mice.

An increasing amount of evidence supports pleiotropic metabolic roles of the cannibinoid-1 receptor (CB1R) in peripheral tissues such as adipose, liver, skeletal muscle and pancreas. To further understand the metabolic consequences of specific blockade of CB1R function in peripheral tissues, we performed a 10-week-study with an anti-sense oligonucleotide directed against the CB1R in diet-induced obese (DIO) AKR/J mice. DIO AKR/J mice were treated with CB1R ASO Isis-414930 (6.25, 12.5 and 25 mg/kg/week) or control ASO Isis-141923 (25 mg/kg/week) via intraperitoneal injection for 10 weeks. At the end of the treatment, CB1R mRNA from the 25 mg/kg/week CB1R ASO group in the epididymal fat and kidney was decreased by 81% and 63%, respectively. Body weight gain was decreased in a dose-dependent fashion, significantly different in the 25 mg/kg/week CB1R ASO group (46.1±1.0 g vs veh, 51.2±0.9 g, p<0.05). Body fat mass was reduced in parallel with attenuated body weight gain. CB1R ASO treatment led to decreased fed glucose level (at week 8, 25 mg/kg/week group, 145±4 mg/dL vs veh, 195±10 mg/dL, p<0.05). Moreover, CB1R ASO treatment dose-dependently improved glucose excursion during an oral glucose tolerance test, whereas control ASO exerted no effect. Liver steatosis was also decreased upon CB1R ASO treatment. At the end of the study, plasma insulin and leptin levels were significantly reduced by 25 mg/kg/week CB1R ASO treatment. SREBP1 mRNA expression was decreased in both epididymal fat and liver. G6PC and fatty acid translocase/CD36 mRNA levels were also reduced in the liver. In summary, CB1R ASO treatment in DIO AKR/J mice led to improved insulin sensitivity and glucose homeostasis. The beneficial effects of CB1R ASO treatment strongly support the notion that selective inhibition of the peripheral CB1R, without blockade of central CB1R, may serve as an effective approach for treating type II diabetes, obesity and the metabolic syndrome

Plasma creatinine, BUN, lipase, ALT and AST levels at the end of treatment.

<p>Values shown are mean ± se. One way ANOVA Dunnett’s multiple test compared to DIO Veh, *p<0.05.</p

A. Body weight during the treatment.

<p>B. Body weight change (% of the beginning body weight) during the treatment. One way ANOVA Dunnett’s multiple test compared to DIO Veh, *p<0.05.</p

Fat mass change before and after 10-week treatment.

<p>One way ANOVA Dunnett’s multiple test compared to DIO Veh, *p<0.05.</p

Oral glucose tolerance test (A and B).

<p>On Day 64, overnight fasted mice were challenged with oral glucose dosing at 2 g/kg. Blood glucose was measured at 0, 30, 60 and 120 minute after glucose dosing. Glucose area under curve was also calculated. C. Fed blood glucose was measured on day 1 and day 54. Student t-test vs the vehicle group, *, P<0.05.</p

mRNA levels of several genes in epididymal fat and liver at the end of the study.

<p>Values shown are mean ± se. Student t- test, compared to DIO Veh, *p<0.05.</p

Liver, spleen and epididymal fat weights, liver TG and plasma total PAI-1 at the end of treatment.

<p>Values shown are mean ± se. One way ANOVA Dunnett’s multiple test compared to DIO Veh, *p<0.05.</p