[Effect of Tanshinone IIA on phosphorylated NMDA receptor 1 expression and intracellular free calcium concentration in neonatal SD rats with hypoxic ischemic brain damage].
OBJECTIVE
To determine the effect of Tanshinone IIA (TanIIA) on the phosphory-lated NMDA receptor 1 at Serine 897 site (phospho-NR1 S897) and intracellular free calcium concentration ([Ca(2+)](i)) in neonatal SD rats with hypoxic ischemic brain damage (HIBD), and to explore the neuroprotective mechanism of TanIIA in HIBD.


METHODS
Neonatal SD rats were randomly divided into a normal control, and an HIBD and TanIIA+HIBD group. Rice-Vannucci method was used for HIBD animal model. Time points were: 3, 6, 12, and 24 h after HIBD (n=10 in each group at each time point). TanIIA was intraperitoneally given at 1 μg/g every 12 h. Fura-2AM was used to mark the fluorescent calcium probe and [Ca(2+)](i) was measured by a Hitachi F-4500 Fluorescence Spectrophometer. Fluorescent immunohisotichemical study was used for the expression of phospho-NR1 S897.


RESULTS
(1) Compared with the normal control group, both the [Ca(2+)](i) absolute number and ipsi-/contra-lateral ratio were increased at each time point with statistical significance (P<0.05). Compared with the HIBD group, the [Ca(2+)](i) in the HIBD+ TanIIA group was decreased at each time point. At 24 h after HIBD, the ipsi-/contra-lateral ratio of HIBD+ TanIIA group was 24.9% less than that of HIBD group with statistical significance (P<0.05). (2) In the normal control group, abundant phospho-NR1 S897 positive cells were nicely distributed in the cortex. Compared with the normal control group, at each time point, both the absolute number of phospho-NR1 S897 positive cells and the fluorescent intensity of phospho-NR1 S897 in the ipsilateral cortex of the HIBD group were decreased with statistical significance (P<0.05). Compared with the HIBD group, both the absolute number of phospho-NR1 S897 positive cells and the fluorescent intensity of phospho-NR1 S897 in the ipsilateral cortex of HIBD+ TanIIA were increased. There was significant difference at 3 and 12 h after the HIBD (P<0.05).


CONCLUSIONS
TanIIA reduced the HIBD-caused down-regulation of phospho-NR1 S897 and the HIBD-caused [Ca(2+)](i) elevation in the cortex. The neuroprotective effect of TanIIA may be related to influencing NMDA receptor expression and decreasing intracellular free calcium aggregation.
Hei
Mingyan
M
Department of Pediatrics, Third Xiangya Hospital, Central South University, Changsha, China. heiming_yan@yahoo.com.cn
Liu
Furong
F
Luo
Yali
Y
D045784:Abietanes / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism*; D005260:Female; D020925:Hypoxia-Ischemia, Brain / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D010766:Phosphorylation; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism*
D045784:Abietanes; D002118:Calcium; D018696:Neuroprotective Agents; D016194:Receptors, N-Methyl-D-Aspartate; C021751:tanshinone