[Prevention of central pontine myelinolysis in rats by early treatment with dexamethasone].
To explore the effect and mechanism of dexamethasone (DEX) in the prevention of central pontine myelinolysis (CPM) in rats.



Hyponatremia was induced in rat by subcutaneous injection of Vasopressin Tannate and intraperitoneal injection of 2.5% dextrose in water for 3 d, the rats of Group A received a bolus of 1 mol/L NaCl (2 ml/kg) and DEX (5 mg/kg) simultaneously at the 4th day; the rats of Group B were treated with DEX after 24 h of the injection of 1 mol/L NaCl; the rats in Group C received a bolus of 1 mol/L NaCl and saline simultaneously; Group D was the control group. The demyelinative lesions were evaluated by myelin staining. The Evans blue (EB) contents of brain were detected to evaluate the blood-brain-barrier permeability after rapid correction of hyponatremia. The expression of inducible nitric oxide synthase (iNOS) in brains was evaluated by Western blotting.



CPM was induced successfully in rats. The EB contents of Group A, B and C had no significant difference at 0 h after injection of hypertonic saline compared with Group D. The EB contents of Group C began to increase significantly at 6 h after injection of hypertonic saline, peaked at 24 h; the expression of iNOS in brains began to increase after 3 h after the rapid correction of hyponatremia. The rate of morbidity in Group C was 66.7%. The demyelinative lesions were rarely seen in Group A, the EB contents of brain decreased significantly compared with Group C at the same time point (P<0.05), the iNOS expression was also inhibited. DEX could not prevent the attack of CPM at Group B, the rate of morbidity (75%) had no significant difference compared with Group C (P>0.05).



Early treatment with DEX can protect blood-brain-barrier and inhibit the expression of iNOS to prevent the attack of CPM.
Ke
Qing-hong
QH
Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.
Chen
Jian-hua
JH
Zheng
Shu-shen
SS
Yu
Jun
J
Liang
Ting-bo
TB
D000818:Animals; D001127:Arginine Vasopressin; D001812:Blood-Brain Barrier / Q000187:drug effects* / Q000503:physiopathology; D003907:Dexamethasone / Q000627:therapeutic use*; D005938:Glucocorticoids / Q000627:therapeutic use; D005947:Glucose; D008297:Male; D017590:Myelinolysis, Central Pontine / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014667:Vasopressins
D005938:Glucocorticoids; C016671:pitressin tannate; D014667:Vasopressins; D001127:Arginine Vasopressin; D003907:Dexamethasone; D052247:Nitric Oxide Synthase Type II; D005947:Glucose