α, ß-Amyrin prevents steatosis and insulin resistance in a high-fat diet-induced mouse model of NAFLD via the AMPK-mTORC1-SREBP1 signaling mechanism

Nonalcoholic fatty liver disease (NAFLD), characterized by hepatosteatosis and steatohepatitis, is intrinsically related to obesity. Our previous study reported on the anti-obese activity of α,β-amyrin (AMY), a pentacyclic triterpene isolated from Protium heptaphyllum. This study investigated its ability to prevent fatty liver and the underlying mechanism using the mouse model of NAFLD. NAFLD was induced in male Swiss mice fed a high fat diet (HFD) for 15 weeks. The controls were fed a normal chow diet (ND). The mice were simultaneously treated with AMY at 10 and 20 mg/kg or fenofibrate at 50 mg/kg. Lipid levels along with metabolic and inflammatory parameters were assessed in liver and serum. The liver sections were histologically examined using H&E staining. RT-qPCR and western blotting assays were performed to analyze signaling mechanisms. Mice fed HFD developed severe hepatic steatosis with elevated triglycerides and lipid droplets compared with ND controls. This was associated with a decrease in AMP-activated protein kinase (AMPK) activity, an increase of mechanistic target of rapamycin complex 1 (mTORC1) signaling, and enhanced sterol regulatory element binding protein 1 (SREBP1) expression, which have roles in lipogenesis, inhibition of lipolysis, and inflammatory response. AMY treatment reversed these signaling activities and decreased the severity of hepatic steatosis and inflammatory response, evidenced by serum and liver parameters as well as histological findings. AMY-induced reduction in hepatic steatosis seemed to involve AMPK-mTORC1-SREBP1 signaling pathways, which supported its beneficial role in the prevention and treatment of NAFLD.

Acute blockade of endogenous melatonin by Luzindole, with or without peripheral LPS injection, induces jejunal inflammation and morphological alterations in Swiss mice

This study investigated the acute blockade of endogenous melatonin (MLT) using Luzindole with or without systemic lipopolysaccharide (LPS) challenge and evaluated changes in inflammatory and oxidative stress markers in the mouse jejunum. Luzindole is an MT1/MT2 MLT receptor antagonist. Both receptors occur in the small intestine. Swiss mice were treated with either saline (0.35 mg/kg, ip), Luzindole (0.35 mg/kg, ip), LPS (1.25 mg/kg, ip), or Luzindole+LPS (0.35 and 1.25 mg/kg, ip, respectively). Jejunum samples were evaluated regarding intestinal morphometry, histopathological crypt scoring, and PAS-positive villus goblet cell counting. Inflammatory Iba-1, interleukin (IL)-1β, tumor necrosis factor (TNF)-α, nuclear factor (NF)-kB, myeloperoxidase (MPO), and oxidative stress (NP-SHs, catalase, MDA, nitrate/nitrite) markers were assessed. Mice treated with Luzindole, LPS, and Luzindole+LPS showed villus height shortening. Crypt damage was worse in the LPS group. Luzindole, LPS, and Luzindole+LPS reduced the PAS-goblet cell labeling and increased Iba-1-immunolabelled cells compared to the saline group. Immunoblotting for IL-1β, TNF-α, and NF-kB was greater in the Luzindole group. The LPS-challenged group showed higher MPO activity than the saline and Luzindole groups. Catalase was reduced in the Luzindole and Luzindole+LPS groups compared to saline. The Luzindole group showed an increase in NP-SHs, an effect related to compensatory GSH activity. The acute blockade of endogenous MLT with Luzindole induced early changes in inflammatory markers with altered intestinal morphology. The other non-detectable deleterious effects of Luzindole may be balanced by the unopposed direct action of MLT in immune cells bypassing the MT1/MT2 receptors.

Atividade antiulcerogênica do extrato aquoso da Bryophyllum pinnatum (Lam. ) Kurz / Antiulcerogenic activity of aqueous extract from Bryophyllum pinnatum (Lam. ) Kurz

Bryophyllum pinnatum (Lam.) Kurz pertence a família Crassulaceae e é conhecida vulgarmente como coirama, folha-da-fortuna, ou folha-do-ar, sendo usada popularmente como antifúngico, no tratamento da hipertensão, em úlceras e em inflamações. O presente estudo objetivou analisar a atividade antiulcerogênica do extrato aquoso das folhas de Bryophyllum pinnatum (Lam.) Kurz em modelo de úlcera gástrica induzida por indometacina em Rattus norvegicus, machos (150 a 250 g) com idade de 70 dias. Os animais receberam por via oral: água, extrato aquoso de Bryophyllum pinnatum (Lam.) Kurz (1 e 2 g Kg-1 ) ou ranitidina (60 mg Kg-1 ), fármaco com ação gastroprotetora conhecida que atua bloqueando os receptores de histamina H2. Após uma hora dos tratamentos, todos animais receberam indometacina via intraperitoneal. Os resultados demonstraram que o extrato aquoso da Bryophyllum pinnatum (Lam.) Kurz possui ação gastroprotetora; na dose de 1 g Kg-1 inibiu 45,49% o índice de ulceração induzido pela indometacina, e, na dose de 2 g Kg-1, inibiu 49,50%. Sugere-se o envolvimento de vários mecanismos na ação gastroprotetora dessa planta e não somente uma possível participação das prostaglandinas nesse efeito. Estudos futuros com diferentes modelos de indução de úlcera gástrica tornam-se necessários para melhor avaliar a atividade antiulcerogênica do extrato aquoso de Bryophyllum pinnatum (Lam.) Kurz.

Bryophyllum pinnatum (Lam.) Kurz belongs to the family Crassulaceae, is popularly known as "coirama", "folha-da-fortuna", or "folha-do-ar" and has been commonly used as antifungal, in the treatment of hypertension, ulcers and inflammation. The present study aimed to analyze the antiulcerogenic activity of aqueous extract from the leaves of Bryophyllum pinnatum (Lam.) Kurz using indomethacin-induced gastric ulcer models in Rattus norvegicus, males (150-250 g) aged 70 days old. The animals received by the oral route: water, aqueous extract from Bryophyllum pinnatum (Lam.) Kurz (1 and 2 g Kg-1) or ranitidine (60 mg Kg-1), a drug with known gastroprotective action, blocking histamine H2-receptors. After one hour of treatments, all animals received indomethacin by the intraperitoneal route. Results demonstrated that the aqueous extract from Bryophyllum pinnatum (Lam.) Kurz has gastroprotective action; at 1g kg-1 it inhibited 45.49% of the indomethacin-induced ulcer index, while at 2g Kg-1 it inhibited 49.50%. Several mechanisms of actions are suggested to be involved in the gastroprotective action of this plant, besides the possible participation of prostaglandins in this effect. Further studies using different gastric ulcer-induction models are needed to better evaluate the antiulcerogenic activity of aqueous extract from Bryophyllum pinnatum (Lam.) Kurz.