Anti-inflammatory and Antioxidant Effects of the Microalga Pediastrum boryanum in Carrageenan-Induced Rat Paw Edema

Abstract The potential use of microalgae in health has been the aim of different studies in the last years. This study investigated anti-inflammatory and antioxidant properties of three different extracts of green microalga Pediastrum boryanum in an acute inflammation model in rats. Rats were treated intraperitoneally with lyophilized biomass, the phenolic compounds and the extracellular extracts of P. boryanum before the induction of paw edema by the intraplantar injection of carrageenan. The edema and the levels of interleukin-1β and tumor necrosis factor-α were determined in the hind paw. Oxidative stress markers were analyzed in the liver and hepatic toxicity and genetic damage was evaluated in the blood. The results demonstrated that the three extracts of P. boryanum exhibited pronounced anti-oedematous property and decreased the levels of cytokines. The best results were provided by the phenolic compounds extract, that contains gallic, chlorogenic, protocathecuic and vanillic acid. A reduction in lipid peroxidation was observed after the treatment with lyophilized biomass and the extracellular extract improved the total antioxidant capacity of the liver. Moreover, no DNA damage and hepatic toxicity were observed after administration of P. boryanum extracts. In conclusion, these results suggest that P. boryanum can be an important source of anti-inflammatory compounds.

Coumestrol/hydroxypropyl-ß-cyclodextrin association incorporated in hydroxypropyl methylcellulose hydrogel exhibits wound healing effect: in vitro and in vivo study.

Several beneficial effects on the skin have been reported for coumestrol (COU), such as protection against photoaging and improvement of skin elasticity and thickness in postmenopausal women. However no reports on the effect of COU on wound healing were found. Nevertheless, COU has low aqueous solubility, which is a crucial limitation for biological tests. The present study was designed as a two-step experiment to evaluate the wound healing effect of COU. First, we used fibroblasts and the experimental in vitro artificial wound model, scratch assay, to compare the effects of COU free, dissolved in dimethyl sulfoxide (DMSO) or Dulbecco's modified Eagle's medium (DMEM), or associated with hydroxypropyl-ß-cyclodextrin (HPßCD). The 50 µM (66.1%) and 10 µM (56.3%) COU/HPßCD association induced cell proliferation and migration in inflicted wounds. Subsequently, the in vivo wound healing experimental model (Wistar rats) revealed that COU/HPßCD incorporated into hypromellose (HPMC) hydrogel had similar efficacy in wound healing in comparison to the positive control (Dersani®), with the advantage that 50% wound healing was achieved within a shorter period. In summary, the results successfully demonstrated, for the first time, the wound healing effect of COU/HPßCD incorporated into HPMC hydrogel and describe the feasibility of the biological tests with the use of HPßCD instead DMSO.

Sciatic nerve transection modulates oxidative parameters in spinal and supraspinal regions.

Neuropathic pain is a very common dysfunction caused by several types of nerve injury. This condition leads to a variety of pathological changes in central nervous system regions related to pain transmission. It has been demonstrated that nociception is modulated by reactive oxidative species and treatments with antioxidant compounds produce antinociceptive effects. Thus, the aim of the present study was to investigate oxidative parameters in spinal and supraspinal regions following sciatic nerve transection (SNT). In behavioral assessments, animals showed mechanical allodynia and a significant functional impairment following SNT, measured by von Frey hairs test and sciatic functional index, respectively. Superoxide dismutase activity was increased 3 and 7 days following SNT in cerebral cortex and brainstem. Catalase activity was also increased in cerebral cortex 3 days after SNT. Ascorbic acid levels were decreased 7 days in the spinal cord only in SNT group. We also showed an increase in lipid peroxidation in cerebral cortex and brainstem 3 days after surgery in SNT and sham groups. These results showed that supraspinal regions also exhibit changes in antioxidant activity after SNT and demonstrate an intricate relationship among antioxidant defenses in different regions of the neuro axis related to pain transmission.

Neuropathic pain modifies antioxidant activity in rat spinal cord.

Oxidative stress is an important pathophysiological mechanism of many neurological diseases. Reactive oxygen and nitrogen species have been cited as molecules involved in the nociceptive process. In this study, rats were submitted to sciatic nerve transection (SNT) for induction of neuropathic pain, and enzyme activities of SOD and catalase as well as lipid peroxidation (LPO) were measured in the lumbosacral spinal cord. The results show that LPO was not changed after SNT. SOD activity was reduced 7 days after SNT, while the change in catalase activity occurred on the third and seventh days in both sham and SNT animals. Hyperalgesia in SNT group was detected at the same points in time. These results suggest that SNT was not a strong enough stimulus to deplete all antioxidant content in the spinal cord, since increase in LPO was not detected. However, the role of oxidative stress in nociception can not be excluded.