Preparation and Evaluation of Preventive Effects of Inhalational and Intraperitoneal Injection of Myrtenol Loaded Nano-Niosomes on Lung Ischemia-Reperfusion Injury in Rats

Protective effects of myrtenol against paraquat-induced toxicity in rats

BACKGROUND

Paraquat (PQ) is a widely used pesticide, can cause severe intoxication and respiratory failure. Myrtenol (Mrl), an essential oil derived in various plants, exhibits several biological properties, including anti-inflammatory and antioxidant activities. This study aims to investigate the protective potential of Mrl against oxidative stress and inflammation caused by PQ exposure.

METHODS

Twenty-five Wistar albino rats were divided into the following groups (n = 5 in each group): a control group (treated by dimethyl sulfoxide (DMSO)), a PQ group (exposed to 54 mg/m³ aerosol PQ), and two treatment groups that were exposed to PQ aerosol and administered oral Mrl at doses of 25 mg/kg/day and 50 mg/kg/day, respectively. The final group was exposed to PQ aerosol and treated with oral dexamethasone at a dose of 0.03 mg/kg/day. Various hematological, oxidative, inflammatory, and pathological indices were measured at the conclusion of the treatment period.

RESULTS

PQ decreases the levels or activities of superoxide dismutase (SOD), catalase (CAT), and Thiol, while increasing the levels or activities of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and malondialdehyde (MDA). Mrl restored activites of SOD, and CAT, as well as thiol levels to near-control values while reducing TNF-α, IL-6, and MDA levels. Pathological studies further confirmed the therapeutic effects of Mrl.

CONCLUSION

The results of this study demonstrate the promising therapeutic effects of Mrl against inhaled PQ in rats.

Myrtenol-loaded niosomes can prevent lung ischemia-reperfusion injury model in rats by balancing the Nrf2/Keap1 and NF-κB signaling pathways

Lung Ischemia-reperfusion injury (LIRI) is a risk during lung transplantation that can cause acute lung injury and organ failure. In LIRI, the NF-E2-related factor 2(Nrf2)/ Kelch-like ECH-associated protein 1 (Keap1) signaling pathway and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway are two major pathways involved in regulating oxidative stress and inflammation, respectively. Myrtenol, a natural compound with anti-inflammatory and antioxidant properties, has potential protective effects against IRI. This study aimed to explore the impact of myrtenol encapsulated within niosomes on the prevention of LIRI and examine the role of the two pathways mentioned in this process. Wistar rats were segregated into four groups. Animals received the myrtenol (MN) (32 mg/kg) or vehicle through daily inhalation for a week before LIRI. Expression of IκB, p-IκB, Nrf2, Keap1, Heme Oxygenase-1(HO-1), NF-κB signaling proteins, reactive oxygen species (ROS) level, caspase-3 expression, arterial blood gases, lung edema, and histopathological indices were assessed. Niosomal myrtenol significantly reduced lung edema, ROS, Keap1, p-IκB, NF-kB, Caspase-3, PaCO2 (the carbon dioxide pressure in arterial blood), and histopathological indices. Additionally, the expression of IκB, Nrf2, HO-1, and PaO2 (the oxygen pressure in arterial blood) increased significantly in the pretreated group compared to the IR group. Overall, inhalation of the niosomal myrtenol protects against lung ischemia-reperfusion injury, presumably through the balance between Nrf2/Keap1 and NF-κB pathways. The findings suggest that the niosomal form of myrtenol may be a potential candidate for developing new drugs to prevent and treat LIR damage.

Quercetin as a therapeutic agent activate the Nrf2/Keap1 pathway to alleviate lung ischemia-reperfusion injury

Lung ischemia-reperfusion injury (LIRI) causes oxidative stress, inflammation, and immune system activation. The Nrf2/Keap1/HO-1 pathway is important in cellular defense against these effects. Quercetin, a flavonoid with antioxidant, anti-inflammatory, and anti-cancer properties, has been investigated. Our aim in this study was to investigate the effect of quercetin on preventing lung ischemia-reperfusion injury and the role of the Nrf2/Keap1/HO-1 pathway. Sixty-four male Wistar rats were divided into four distinct groups(n = 16). Sham, lung ischemia-reperfusion (LIR), Saline + LIR, Quercetin + LIR (30 mg/kg i.p for a week before LIR). LIR groups were subjected to 60 min of ischemia (left pulmonary artery, vein, and bronchus) and 120 min of reperfusion. Our assessment encompassed a comprehensive analysis of various factors, including the evaluation of expression Nrf2, Keap1, and Heme Oxygenase-1 (HO-1) levels and NF-κB protein. Furthermore, we examined markers related to inflammation (interleukin-1β and tumor necrosis factor alpha), oxidative stress (malondialdehyde, total oxidant status, superoxide dismutase, glutathione peroxidase, total antioxidant capacity), lung edema (Wet/dry lung weight ratio and total protein concentration), apoptosis (Bax and Bcl2 protein), and histopathological alterations (intra-alveolar edema, alveolar hemorrhage, and neutrophil infiltration). Our results show that ischemia-reperfusion results in heightened inflammation, oxidative stress, apoptosis, lung edema, and histopathological damage. Quercetin showed preventive effects by reducing these markers, acting through modulation of the Nrf2/Keap1 pathway and inhibiting the NF-κB pathway. This anti-inflammatory effect, complementary to the antioxidant effects of quercetin, provides a multifaceted approach to cell protection that is important for developing therapeutic strategies against ischemia-reperfusion injury and could be helpful in preventive strategies against ischemia-reperfusion.

High-intensity intermittent training ameliorates methotrexate-induced acute lung injury

Inflammation and oxidative stress are recognized as two primary causes of lung damage induced by methotrexate, a drug used in the treatment of cancer and immunological diseases. This drug triggers the generation of oxidants, leading to lung injury. Given the antioxidant and anti-inflammatory effects of high-intensity intermittent training (HIIT), our aim was to evaluate the therapeutic potential of HIIT in mitigating methotrexate-induced lung damage in rats. Seventy male Wistar rats were randomly divided into five groups: CTL (Control), HIIT (High-intensity intermittent training), ALI (Acute Lung Injury), HIIT+ALI (pretreated with HIIT), and ALI + HIIT (treated with HIIT).HIIT sessions were conducted for 8 weeks. At the end of the study, assessments were made on malondialdehyde, total antioxidant capacity (TAC), superoxide dismutase (SOD), glutathione peroxidase (Gpx), myeloperoxidase (MPO), interleukin 10 (IL-10), tumor necrosis factor-alpha (TNF-α), gene expression of T-bet, GATA3, FOXP3, lung wet/dry weight ratio, pulmonary capillary permeability, apoptosis (Caspase-3), and histopathological indices.Methotrexate administration resulted in increased levels of TNF-α, MPO, GATA3, caspase-3, and pulmonary edema indices, while reducing the levels of TAC, SOD, Gpx, IL-10, T-bet, and FOXP3. Pretreatment and treatment with HIIT reduced the levels of oxidant and inflammatory factors, pulmonary edema, and other histopathological indicators. Concurrently, HIIT increased the levels of antioxidant and anti-inflammatory factors.