The effect of cannabis on oxidative stress and neurodegeneration induced by intrastriatal rotenone injection in rats

Abstract

We investigated the effect of cannabis treatment on the development of oxidative stress and nigrostriatal cell injury induced by intrastriatal rotenone injection in rats. Rotenone was injected into the right striatum at a concentration of 5 mM (3 μl/rat). The control rats received the vehicle (DMSO). Subsequently, the effect of Cannabis sativa extract treatment on rotenone toxicity was evaluated. Starting on the second day of rotenone injection, rats were treated with C. sativa extract (5, 10, or 15 mg/kg) (expressed as Δ9-tetrahydrocannabinol) subcutaneously (s.c.) once daily for 30 days. Biochemical markers of oxidative stress, malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide, paraoxonase 1 (PON1) activity, catalase activity, as well as tumor necrosis factor alpha (TNF-α), were determined in different brain areas after 30 days of rotenone treatment. Histopathology and immunohistochemical expression of tyrosine hydroxylase (TH), capase 3, and inducible nitric oxide synthase (iNOS) were also performed. Results showed that intrastriatal injection of rotenone resulted in increased brain oxidative stress in the cerebral cortex, striatum, hippocampus, midbrain, and cerebellum. MDA increased by 41.4–70 %, nitric oxide increased by 48.3–77.5 %, while GSH decreased by 25.0–34.2 %. PON1 and catalase activities decreased by 43.0–60.8 % and by 14.2–36 %, respectively, in these areas. Striatal TNF-α increased by 638.9 % of control value after rotenone injection. Rotenone induced motor deficits (decreased rearing activity). Rotenone caused marked nigrostriatal neurodegeneration, decreased TH immunoreactivity, and increased both iNOS and caspase 3 immunoreactivities in the striatum. Cannabis decreased brain oxidative stress and nitric oxide release induced by intrastriatal rotenone in several brain areas. Cannabis also decreased the elevated TNF-α in the striatum. Cannabis did not protect against the immunohistochemical changes in the striatum and substantia nigra or against neuronal degeneration induced by rotenone treatment. Collectively, these results indicated that the administration of cannabis did not protect against nigrostriatal damage caused by intrastriatal rotenone.