ABSTRACT
Polymer-drug conjugates (PDCs) have been extensively studied as nanocarriers for anti-tumor drugs delivery due to excellent stability in circulation and high drug loading ability. Stimuli-responsive PDCs(SRPDCs) could release the loading drug in response to various intra-or extracellular biological stimulis (eg, acidic pH, altered redox potential, and upregulated enzyme), as well as external artificial stimulis (eg, magnetic feld, light, temperature, and ultrasound), which are considered as "smart" nanocarriers for delivery of anti-tumor drugs. In this article, recent progresses in the development of SRPDCs for cancer therapy are reviewed, covering the design, smart linkages as well as responsive drug release property, so as to provide reference for the development of related drug delivery systems. In order to improve the successful translation of stimuli-responsive PDCs, drawbacks and limitations of current researches are discussed, besides, future perspectives and research strategies are also provided.
ABSTRACT
<p><b>OBJECTIVE</b>To determine the effects of Jiji decoction (Traditional Chinese Medicine) on the cognitive function and oxidative stress in mice with vascular dementia (VD) induced by cerebral ischemia/reperfusion.</p><p><b>METHODS</b>Thirty-two mice were randomly divided into nonnal group (n = 8), sham group (operation, but no cerebral ischemia/reperfusi6n, n = 8), model group (vascular dementia model induced by cerebral ischemia/reperfusion, n = 8), and Jiji decoction-treated group (vascular dementia model plus treatment with Jiji decoction, n = 8). Fourteen days of treatment after operation, the cognitive behavior was measured in step-through test, spatial probe test and platform test. Afterwards, to assess the levels of oxidative stress, the activity of superoxide dismutase(SOD) and content of malonaldehyde (MDA) in brain of these mice were measured.</p><p><b>RESULTS</b>Data from step-through test indicated that the escaping latency of Jiji decoction-treated group was prolonged and the error counts were decreased significantly ( P <0.01) compared with those of model group. Data from spatial probe test indicated that the time of entering darkroom, the time of climbing height and the time of entering bright room in Jiji decoction-treated group were shortened and the counts of climbing height were increased (P < 0.05-0.01) significantly compared with those of model group. Data from platform test showed that the escaping latency of Jiji decoction-treated group was prolonged significantly (P < 0.01) compared with that of model group. Compared with normal and sham group, the activity of SOD was decreased and the content of MDA was increased in model group significantly (P < 0.01). Compared with those of model group, the levels of SOD and MDA in Jiji decoction-treated group were improved significantly (P < 0.01).</p><p><b>CONCLUSION</b>Jiji decoction could improve cognitive function of VD mice. Its mechanism might be related with the inhibition of oxidative stiess in the brain.</p>