Carbon Nanodots Attenuate Lipid Peroxidation in the LDL Receptor Knockout Mouse Brain.

Abnormal cholesterol metabolism can lead to oxidative stress in the brain. Low-density lipoprotein receptor (LDLr) knockout mice are models for studying altered cholesterol metabolism and oxidative stress onset in the brain. Carbon nanodots are a new class of carbon nanomaterials that possess antioxidant properties. The goal of our study was to evaluate the effectiveness of carbon nanodots in preventing brain lipid peroxidation. LDLr knockout mice and wild-type C57BL/6J mice were treated with saline or 2.5 mg/kg bw of carbon nanodots for a 16-week period. Brains were removed and dissected into the cortex, midbrain, and striatum. We measured lipid peroxidation in the mouse brain tissues using the Thiobarbituric Acid Reactive Substances Assay and iron and copper concentrations using Graphite Furnace Atomic Absorption Spectroscopy. We focused on iron and copper due to their association with oxidative stress. Iron concentrations were significantly elevated in the midbrain and striatum of the LDLr knockout mice compared to the C57BL/6J mice, whereas lipid peroxidation was greatest in the midbrain and cortex of the LDLr knockout mice. Treatment with carbon nanodots in the LDLr knockout mice attenuated both the rise in iron and lipid peroxidation, but they had no negative effect in the C57BL/6J mice, indicating the anti-oxidative stress properties of carbon nanodots. We also assessed locomotor and anxiety-like behaviors as functional indicators of lipid peroxidation and found that treatment with carbon nanodots prevented the anxiety-like behaviors displayed by the LDLr knockout mice. Overall, our results show that carbon nanodots are safe and may be an effective nanomaterial for combating the harmful effects caused by lipid peroxidation.

Method for Removing Thawed Human Milk From a Plastic Storage Bag Impacts Fat Retention.

OBJECTIVES: Determine how thaw stage and bag manipulation (folding and squeezing) influence the retention of fat and number of aerobic bacteria colony-forming units when decanting human milk (HM) from plastic storage bags. METHODS: Lactating women (n = 40) in the Greensboro, North Carolina area were recruited to provide fresh HM. Samples were equally divided and frozen in storage bags for 2 months. Two thaw stages (ice/liquid) and the use of bag manipulation (yes/no) were assessed. Fat was measured using ether extraction and bacteria were measured using plate enumeration. Paired t tests were used to compare the effects of thaw stage and bag manipulation on post-thaw fat content. Repeated measures analysis of variance was used to compare the effect of bag manipulation on pre- and post-thaw bacteria. RESULTS: Fat retention was not significantly different when thawing to liquid versus ice (mean difference = 0.10 g/dL; n = 17 paired samples; P = 0.07). Decanting with bag manipulation retained more fat than decanting without manipulation, but only when HM was thawed to liquid (mean difference = 0.13 g/dL; n = 11 paired samples; P = 0.005), not when HM was thawed to ice (P = 0.47). Bag manipulation did not increase total aerobic bacteria for either thaw stage (P = 0.49). CONCLUSIONS: Fat retention is influenced by the method of removing previously frozen HM from plastic storage bags. Folding and squeezing the storage bag when decanting HM thawed to a liquid state increases fat recovery without increasing bacterial contamination.