Effects of Perilla frutescens var. acuta in amyloid ß toxicity and Alzheimer's disease-like pathology in 5XFAD mice.

Although accumulation of amyloid ß (Aß) plaque is a major hallmark of Alzheimer's disease (AD), various pathologies have been suggested therapeutic targets. Therefore, therapies-targeting multiple pathologies would be required for effective managements of AD. Accordingly, natural products, which has multiple active ingredients, have been receiving a lot of attention. In this study, we tested whether standardized ethanol extract of leaves of Perilla frutescens var. acuta (L.) Britt. (Lamiaceae) (ELPF) could modulate various pathologies in AD using 5XFAD mice. ELPF blocked Aß aggregation and disassembled pre-formed Aß aggregates. ELPF blocked Aß aggregates-induced LTP impairment and ELPF-disassembled Aß aggregates failed to impair hippocampal LTP. Systemic administration of ELPF blocked Aß aggregates-induced memory impairment in a passive avoidance test. ELPF-disassembled Aß aggregates failed to impair passive avoidance memory. Prolonged administration of ELPF ameliorated memory impairments in 5XFAD mice. In the hippocampus of 5XFAD mice, ELPF administration significantly reduced Aß deposits and neuroinflammation. These results demonstrate that ELPF could be a promising therapeutic candidate for AD.

Rat pancreatitis produced by 13-week administration of zinc oxide nanoparticles: biopersistence of nanoparticles and possible solutions.

Zinc oxide (ZnO) nanoparticles (NPs) are used in diverse applications ranging from paints and cosmetics to biomedicine and food. Although micron-sized ZnO is a traditional food supplement, ZnO NPs are an unknown public health risk because of their unique physicochemical properties. Herein, we studied the 13-week subchronic toxicity of ZnO NPs administered via the oral route according to Organization for Economic Cooperation and Development (OECD) test guideline 408. Well-dispersed ZnO NPs were administered to Sprague-Dawley (SD) rats (11/sex/group) at doses of 67.1, 134.2, 268.4 or 536.8 mg kg(-1) per body weight over a 13-week period. The mean body weight gain in males given 536.8 mg kg(-1) ZnO NPs was significantly lower than that of control male rats, whereas no significant differences were observed between the other treatment groups and the controls. Male and female rats dosed at 536.8 mg kg(-1) ZnO NPs had significant changes in anemia-related hematologic parameters. Mild to moderate pancreatitis also developed in both sexes dosed at 536.8 mg kg(-1) , whereas no histological changes were observed in the other treatment groups. To evaluate the mechanism of toxicity, we performed a bio-persistence study and evaluated the effects of the ZnO NPs on cell proliferation. The treatment of a human gastric adenocarcinoma cell line with ZnO NPs resulted in a significant inhibition of cellular proliferation. The anti-proliferative effect of ZnO NPs or Zn(2+) was effectively blocked by treatment with chelators. These results indicate that the bio-persistence of ZnO NPs after ingestion is key to their toxicity; the no-observed-adverse effect level (NOAEL) of ZnO NPs was found to be 268.4 mg kg(-1) per day for both sexes.

Transient pulmonary fibrogenic effect induced by intratracheal instillation of ultrafine amorphous silica in A/J mice.

In order to evaluate the degree of pulmonary fibrosis and to identify the fibrogenic mechanisms induced by ultrafine amorphous silica (UFAS), UFAS suspensions ( approximately 50microl) were instilled intratracheally into A/J mice at doses of 0, 2, 10 and 50mg/kg (n=5 per group). Mice were sacrificed at 24h, 1, 4 and 14 weeks after exposure. Gomori's trichrome staining revealed that UFAS induced severe alveolar epithelial thickening and pulmonary fibrosis at 1 week, though animals almost recovered at 4 and 14 weeks. The mRNA and protein levels of cytokines (IL-4, IL-10, IL-13 and IFN-gamma), matrix metalloproteinases (MMP-2, MMP-9 and MMP-10) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in lung tissues were significantly elevated at 24h and 1week post-treatment, though these levels decreased to near the control range at 4 and 14 weeks except IFN-gamma and MMP-2. These results demonstrate that UFAS can induce pulmonary fibrosis in the same way as crystalline silica. However, the degree of fibrosis observed was transient. This study shows that cytokines (IL-4, IL-10, IL-13 and IFN-gamma), MMPs (MMP-2, MMP-9 and MMP-10) and TIMP-1 play important roles in the fibrosis induced by the intratracheal instillation of UFAS.