The protective effects of procyanidin supplementation on PM2.5-induced acute cardiac injury in rats.

OBJECTIVE: Numerous epidemiological and experimental studies have indicated that ambient fine particulate matter (PM2.5) exposure can lead to myocardial injury by inhibiting oxidative stress and apoptosis. The effects of procyanidin (PC) on PM2.5-induced cardiovascular diseases (CVDs) are still unknown. The purpose of this study was to explore the protective effect of PC supplementation on PM2.5-induced oxidative stress and cardiomyocyte apoptosis in rats. METHOD: Rats were treated by gavage with three different PC concentrations (50, 100 and 200 mg/kg) for 21 days prior to exposure to 10 mg/kg PM2.5 suspension liquid by intratracheal instillation every other day for three times. We determined myocardial reactive oxygen species (ROS) and malondialdehyde (MDA) levels. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the myocardium were measured. The expression levels of apoptosis-related proteins, including p-Akt/Akt, Bcl-2, caspase-3 and Bax, were determined. In addition, histopathological examination was used to evaluate cardiac injury. RESULTS: PM2.5 exposure noticeably elevated the contents of MDA and ROS and decreased the activities of GSH-Px and SOD. PM2.5 exposure inhibited Bcl-2 expression and up-regulated caspase-3 and Bax expression in the myocardium of rats. The anti-apoptosis-related index p-Akt/Akt was reduced. Moreover, pretreatment with PC could attenuate these PM2.5-induced changes. However, remarkable differences in the protective effect of different PC doses did not exist. CONCLUSIONS: The results indicated that PC supplementation could effectively attenuate the oxidative stress and apoptosis induced by PM2.5 in rat myocardial tissue.

Novel Donor-Acceptor Conjugated Polymer-Based Nanomicelles for Photothermal Therapy in the NIR Window.

In this study, a novel donor-acceptor conjugated polymer PDPPDTP was designed and synthesized by D-A polymerization using 2,6-di(trimethyltin)-N-dithieno[3,2-b:20,30-d]pyrrole as the electron-donating (D) unit and 3,6-bis(5-bromothiophen-2-yl)-2,5-dihexadecylpyrrolo[3,4-c]pyrrole-1,4-dione as the electron-accepting (A) unit. The prepared polymer has strong absorption in the near-infrared (NIR) range of 700-900 nm. Moreover, it shows excellent photothermal performance under irradiation at 808 nm. Next, the biodegradable amphiphilic polymer polyethylene glycol-polycaprolactone was used to encapsulate the new conjugated polymer into nanomicelles by the microemulsion method. The obtained PDPPDTP-loaded micelles exhibited a regular spherical structure, and their hydrodynamic diameter was about 78 nm, characterized by transmission electron microscopy and dynamic light scattering. Notably, the micelles exhibited good stability, and the encapsulation efficiency of the conjugated polymer in the micelles was ∼80%. In vitro cell experiments demonstrated that the nanomicelles not only showed good biocompatibility and low toxicity but also could effectively inhibit the proliferation of breast cancer cells 4T1 under the NIR light irradiation of 808 nm. Furthermore, in vivo studies of photothermal therapy (PTT) efficacy showed that the PDPPDTP-loaded micelles exhibited a remarkable tumor growth inhibition in a syngeneic murine tumor model, indicating that the nanomicelles loaded with this novel conjugated polymer could be further explored as a new type of theranostic agent and applied in the PTT of tumors.