Oleanolic acid-based therapeutics ameliorate rotenone-induced motor and depressive behaviors in parkinsonian male mice via controlling neuroinflammation and activating Nrf2-BDNF-dopaminergic signaling pathways

Parkinson's disease (PD) is often accompanied by depression, which may appear before motor signs. Oleanolic acid (OA), a pentacyclic triterpenoid substance, have many pharmacological properties. However, its efficacy in treating PD-related chronic unpredictable stress (CUS) is unknown. Our study used behavioral, biochemical, and immunohistochemical techniques to assess how OA affected PDrelated CUS. Rotenone (1 mg/kg i.p. for first 21 days) was used to induce Parkinsonism, and modest psychological & environmental stresses generated CUS (from day 22 to day 43) in animals. The study included daily i.p.administration of OA (5, 10, and 20 mg/kg) from day 1 to day 57 in male swiss albino mice. Animals were evaluated for behavioral, biochemical parameters, neurotransmitters, and immunohistochemical expression following the treatment. Results of the study revealed that treatment with OA at all doses alleviated the core symptoms of CUS linked to PD and improved motor and non-motor function. OA therapy significantly lowered IL-1β, TNF-α (p < 0.01, < 0.01, < 0.001), IL-6 (p < 0.05, < 0.01, < 0.001), oxidative stress (p < 0.05, < 0.01, < 0.01), and elevated norepinephrine (p < 0.05, < 0.01, < 0.01), dopamine, and serotonin (p < 0.05, < 0.01, < 0.001) levels. Moreover, OA therapy substantially reduced α-synuclein (p < 0.05, < 0.01, < 0.01) aggregation and increased BDNF (p < 0.05, < 0.01, < 0.001) & Nrf-2 (p < 0.05, < 0.01, < 0.01) levels, which boosts neuronal dopamine survival. The study's findings indicated that OA ameliorates depressive-like behavior persuaded by CUS in PD, decreases neuroinflammation, and improves neurotransmitter concentration via activating Nrf2-BDNF-dopaminergic pathway.

Acute and sub-acute toxicity study reveals no dentrimental effect of formononetin in mice upon repeated i.p. dosing

AIM

Formononetin is a phytoestrogen which possess different pharmacological activities. The intraperitoneal route permits the identification of target organs involved in toxicity without compromising the molecule's bioavailability. The current study investigated the safety profile of intraperitoneal formononetin in Swiss albino mice.

MATERIAL AND METHODS

For acute toxicity study, formononetin administered intraperitoneally to mice at the doses of 5, 50, 100, 150, 200, and 300 mg/kg for 14 days. For the subacute toxicity study, mice were intraperitoneally administered with formononetin (12.5, 25, and 50 mg/kg) daily for 28 days.

RESULTS

During the acute study, no deteriorating effect was observed on body weight, food and water intake, no behavioral changes were observed in animals. The lethal dose 50% (LD50) of formononetin was determined to be 103.6 mg/kg of BW, with a no observed adverse effect level (NOAEL) of 50 mg/kg of BW. Mortality was observed in the 300 mg/kg dose group and histopathological changes such as a mild degree of diffuse granular degeneration in the liver but for rest all doses did not have any adverse effect. In subacute study, no signs of adverse effects, mortality, no changes in body weight, food and water intake, and hematological and biochemical parameters were observed. Histopathology of subacute study indicates, formononetin did not have any noxious effect on organs.

CONCLUSION

Formononetin shows mortality at acute dose 300 mg/kg and LD50 at 103.6 mg/kg of BW, with a NOAEL of 50 mg/kg of BW, rest all doses for acute and sub-acute are safe when given intraperitoneally.

Novel therapeutic approaches for Parkinson's disease by targeting brain cholesterol homeostasis

OBJECTIVES

Human brain is composed of 25% of the cholesterol & any dysfunction in brain cholesterol homeostasis contributes to neurodegenerative disorders such as Parkinson, Alzheimer's, Huntington's disease, etc. A growing literature indicates that alteration in neurotransmission & brain cholesterol metabolism takes place in the early stage of the disease. The current paper summarizes the role of cholesterol & its homeostasis in the pathophysiology of Parkinson's disease.

KEY FINDINGS

Literature findings suggest the possible role of lipids such as oxysterols, lipoproteins, etc. in Parkinson's disease pathophysiology. Cholesterol performs a diverse role in the brain but any deviation in its levels leads to neurodegeneration. Dysregulation of lipid caused by oxidative stress & inflammation leads to α-synuclein trafficking which contributes to Parkinson's disease progression. Also, α-synuclein by binding to membrane lipid forms lipid-protein complex & results in its aggregation. Different targets such as Phospholipase A2, Stearoyl-CoA desaturase enzyme, proprotein convertase subtilisin/kexin type 9, etc. have been identified as a potential novel approach for Parkinson's disease treatment.

SUMMARY

In the current review, we have discussed the possible molecular role of cholesterol homeostasis in Parkinson's disease progression. We also identified potential therapeutic targets that need to be evaluated clinically for the development of Parkinson's treatment.