3-Methyl-4-nitrophenol Exposure Deteriorates Oocyte Maturation by Inducing Spindle Instability and Mitochondrial Dysfunction.

3-methyl-4-nitrophenol (PNMC), a well-known constituent of diesel exhaust particles and degradation products of insecticide fenitrothion, is a widely distributed environmental contaminant. PNMC is toxic to the female reproductive system; however, how it affects meiosis progression in oocytes is unknown. In this study, in vitro maturation of mouse oocytes was applied to investigate the deleterious effects of PNMC. We found that exposure to PNMC significantly compromised oocyte maturation. PNMC disturbed the spindle stability; specifically, it decreased the spindle density and increased the spindle length. The weakened spindle pole location of microtubule-severing enzyme Fignl1 may result in a defective spindle apparatus in PNMC-exposed oocytes. PNMC exposure induced significant mitochondrial dysfunction, including mitochondria distribution, ATP production, mitochondrial membrane potential, and ROS accumulation. The mRNA levels of the mitochondria-related genes were also significantly impaired. Finally, the above-mentioned alterations triggered early apoptosis in the oocytes. In conclusion, PNMC exposure affected oocyte maturation and quality through the regulation of spindle stability and mitochondrial function.

The antityrosinase and antioxidant activities of flavonoids dominated by the number and location of phenolic hydroxyl groups.

BACKGROUND: Compounds with the ability to scavenge reactive oxygen species (ROS) and inhibit tyrosinase may be useful for the treatment and prevention from ROS-related diseases. The number and location of phenolic hydroxyl of the flavonoids will significantly influence the inhibition of tyrosinase activity. Phenolic hydroxyl is indispensable to the antioxidant activity of flavonoids. Isoeugenol, shikonin, baicalein, rosmarinic acid, and dihydromyricetin have respectively one, two, three, four, or five phenolic hydroxyls. The different molecular structures with the similar structure to l-3,4-dihydroxyphenylalanine (l-DOPA) were expected to the different antityrosinase and antioxidant activities. METHODS: This investigation tested the antityrosinase activity, the inhibition constant, and inhibition type of isoeugenol, shikonin, baicalein, rosmarinic acid, and dihydromyricetin. Molecular docking was examined by the Discovery Studio 2.5 (CDOCKER Dock, Dassault Systemes BIOVIA, USA). This experiment also examined the antioxidant effects of the five compounds on supercoiled pBR322 plasmid DNA, lipid peroxidation in rat liver mitochondria in vitro, and DPPH, ABTS, hydroxyl, or superoxide free radical scavenging activity in vitro. RESULTS: The compounds exhibited good antityrosinase activities. Molecular docking results implied that the compounds could interact with the amino acid residues in the active site center of antityrosinase. These compounds also exhibited antioxidant effects on DPPH, ABTS, hydroxyl, or superoxide free radical scavenging activity in vitro, lipid peroxidation in rat liver mitochondria induced by Fe2+/vitamin C system in vitro, and supercoiled pBR322 plasmid DNA. The activity order is isoeugenol < shikonin < baicalein < rosmarinic acid < dihydromyricetin. The results showed the compounds with more phenolic hydroxyls have more antioxidant and antityrosinase activities. CONCLUSION: This was the first study of molecular docking for modeling the antityrosinase activity of compounds. This was also the first study of the protective effects of compounds on supercoiled pBR322 plasmid DNA, the lipid peroxidation inhibition activity in liver mitochondria. These results suggest that the compounds exhibited antityrosinase and antioxidant activities may be useful in skin pigmentation and food additives.

Hepatoprotective effects and antioxidant, antityrosinase activities of phloretin and phloretin isonicotinyl hydrazone.

BACKGROUND: Acute liver damage is primarily induced by one of several causes, among them viral exposure, alcohol consumption, and drug and immune system issues. Agents with the ability to inhibit tyrosinase and protect against DNA damage caused by reactive oxygen species (ROS) may be therapeutically useful for the prevention or treatment of ROS-related diseases. METHODS: This investigation examined the hepatoprotective effects of phloretin and phloretin isonicotinyl hydrazone (PIH) on d-galactosamine (D-GalN)-induced acute liver damage in Kunming mice, as well as the possible mechanisms. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl transferase (γ-GT), alkaline phosphatase (ALP), and total bilirubin (TB) as well as the histopathological changes in mouse liver sections were determined. The antioxidant effects of phloretin, quercetin, and PIH on lipid peroxidation in rat liver mitochondria in vitro, 1,1-diphenyl-2-picrylhydrazyl (DPPH) or 2,2-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) free radical scavenging activity in vitro, and supercoiled pBR322 plasmid DNA were confirmed. The experiment also examined the antityrosinase activity, inhibition type, and inhibition constant of phloretin and PIH. RESULTS: Phloretin, quercetin, or PIH significantly prevented the increase in serum ALT, AST, γ-GT, ALP, and TB in acute liver damage induced by D-GalN, and produced a marked reduction in the histopathological hepatic lesions. Phloretin, quercetin, or PIH also exhibited antioxidant effects on lipid peroxidation in rat liver mitochondria in vitro, DPPH or ABTS free radical scavenging activity in vitro, and supercoiled pBR322 plasmid DNA. Phloretin, quercetin, or PIH also exhibited good antityrosinase activity. CONCLUSION: To the best of our knowledge, this was the first study of the hepatoprotective effects of phloretin and PIH on D-GalN-induced acute liver damage in Kunming mice as well as the possible mechanisms. This was also the first study of the lipid peroxidation inhibition activity of phloretin and PIH in liver mitochondria induced by the Fe(2+)/vitamin C (Vc) system in vitro, the protective effects on supercoiled pBR322 plasmid DNA, and the antityrosinase activity of phloretin and PIH.

[Effect of acupuncture of different acupoints on immune function in rats with exhausted swimming].

OBJECTIVE: To observe the effect of acupuncture of "Zusanli" (ST 36) on immune function in progressively exhausted swimming rats so as to reveal its mechanism underlying improvement of strenuous exercise. METHODS: Thirty-two SD rats were randomly allocated into control group, strenuous exercise (model) group, acupuncture-Xuehai (SP 10) group, Acupuncture-Zusanli (ST 36) group (n = 8/group). The rats were forced to have a swimming in a water tank for 15-90 min in the first 8 days (once daily), then, a progressively exhausted load swimming 1 - 3 times everyday from day 9 to 13. Bilateral SP 10 and ST 36 were punctured with filiform needles and stimulated with uniform reinforcing and reducing manipulation, once daily, after termination of the swimming and for 13 days. Serum interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) contents were assayed by using enzyme linked immunosorbent assay. The rat's body weight and the spleen weight were weighted by using an electronic balance for calculating the spleen index (spleen weight /body weight x 100%) after killing the rat under deep anesthesia. RESULTS: Compared with the model group, the time of swimming-induced exhaustion appearing at the first time from day 9 to day 13 in the SP 10 and ST 36 groups was apparently lengthened (P < 0.01). No significant difference was found between SP 10 and ST 36 groups in the time of swimming-induced exhaustion appearing at the first time of the forced swimming. Compared with the control group, the spleen index, serum IFN-gamma contents and IFN-gamma/IL-4 in the model group were decreased significantly (P < 0.01, P < 0.05). In comparison with the model group, the serum IL-4 contents in the SP 10 and ST 36 groups were decreased markedly (P < 0.05, P < 0.01), and serum IFN-gamma content and IFN-gamma/IL-4 in the ST 36 group were increased significantly (P < 0.05, P < 0.01). The IFN-gamma level was significantly higher in the ST 36 group than in the SP 10 group (P < 0.05). No significant differences were found between SP 10 and ST 36 groups in the spleen index, IL-4 and IFN-gamma/IL-4 (P > 0.05). CONCLUSION: Acupuncture at "Zusanli" (ST 36) can lengthen the time of forced swimming-induced exhaustion, and upregulate serum IFN-gamma content and IFN-gamma/IL-4 in exhausted swimming rats, which may contribute to its effect in correcting Th1/Th2 imbalance after strenuous exercise. The effect of acupuncture of ST 36 is superior to that of acupuncture of SP 10.