Potent protection of Danshensu (β-3, 4-dihydroxyphenyl-lactic acid) against excitotoxic effects of maternal intragastric administration of monosodium glutamate at a late stage of pregnancy on developing mouse fetal brain

Recent studies have demonstrated that ferulic acid[3-（4-hydroxy-3-methoxyphenyl）-2-propenoic acid]and sodium ferulate produce protective effects against glutamate-induced neurotoxicity in adult mice.Danshensu（β-3,4-dihydroxyphenyl-lactic acid）has a similar molecular structure and pharmacological action to caffeic acid.This study aimed to validate the protection conferred by Danshensu against excitotoxic effects of maternal intragastric administration of monosodium glutamate at late stages of pregnancy in the developing mouse fetal brain.Behavioral tests,as well as histopathological and immunohistochemical examination of hippocampi were performed in filial mice.Results revealed that maternal intragastric administration of excessive monosodium glutamate（1.0,2.0,4.0 g/kg body weight）at a late stage of pregnancy resulted in a series of behavioral disorders（hyperactivity,lesions of learning and memory,and disturbance in cooperation of movement ability under high-altitude stress）,histopathological impairment（neuronal edema,degeneration,necrosis,and hyperplasia）and molecular cellular biological changes（upregulated expression of N-methyI-D-aspartate receptor type 1 and neuropeptide Y in the hippocampal region of the brain of the filial mice from mothers treated with monosodium glutamate）.Simultaneous administration of sodium Danshensu partially reversed the effects of monosodium glutamate on the above mentioned phenomena.These findings indicate that sodium Danshensu exhibits obvious protective effects on the excitotoxicity of monosodium glutamate.

Morphological changes and variations in Na+/K+-ATPase activity in the gills of juvenile large yellow croaker (Larimichthys crocea) at low salinity

Gill morphological changes and physiological responses in juvenile large yellow croaker(Larimichthys crocea)were examined upon exposure to low salinity after indoor culture of the fish at salinities of 2,4,6,8,and 24‰(control group).The thickness of the lamellae was significantly higher in the low-salinity groups than in the control group;in contrast,the interlamellar space was significantly lower in the low-salinity groups than in the control group.Additionally,a significant negative correlation was found between the thickness of lamellae and interlamellar spaces(P<0.01).Mitochondria-rich cells(MRCs)were mainly found in the filament at 24‰salinity and proliferated in the lamellae at lower salinities,suggesting that filament and lamellar MRCs are responsible for ion secretion and absorption,respectively.Meanwhile,the activity of Na+/K+-ATPase(NKA)was significantly elevated with the decrease in salinity from 24‰to 4‰(P<0.05),which was consistent with MRCs proliferation.Finally,the activity of NKA declined at 2‰salinity(P<0.05),indicating the limit of osmoregulation,which was consistent with the degeneration and necrosis of the lamellae.Additionally,different levels of gill histopathological lesions,including pavement cell(PVC)exfoliation,lamellar epithelial lifting,edema,fusion,aneurism,and necrosis,were observed from salinities of 24 to 4‰,likely reducing the respiratory efficiency and compromising the health of juvenile fish.In conclusion,large yellow croaker juveniles could improve the osmoregulatory capacity by increasing lamellar MRCs and NKA activity with the decrease in salinity from 24 to 4‰.However,the associated histopathological lesions are likely to negatively influence the fish by affecting respiration and osmoregulation,especially when the salinity is below 4‰.