[Protective effects of baicalin pretreatment on hypoxic-ischemic brain damage in neonatal rats].
OBJECTIVE
Previous research suggests that dexamethasone (Dex) pretreatment protects neonatal rats against hypoxic-ischemic brain damage (HIBD). Some of the pharmacological effects of baicalin (a traditional Chinese medicine extracted from Scutellaria baicalensis Georgi) are similar to Dex. This study was designed to explore the effect of baicalin on the neuronal apoptosis following HIBD in neonatal rats.


METHODS
Six-day-old Sprague-Dawley rats were randomly assigned into Control (without HI), HIBD, Dex-pretreatment and post-treatment, Baicalin-pretreatment and -post-treatment groups. HIBD was induced by ligating the left common carotid artery, followed by exposure to hypoxia. In the pretreatment groups either baicalin (16 mg/kg) or Dex (0.1 mg/kg) was administered to the rats 24 hrs before HIBD; in the post-treatment groups baicalin or Dex was given 30 minutes after HIBD. The rat pups were sacrificed on postnatal day 10, and brain tissues were harvested. Brain water content was determined, morphological changes were observed under a light microscope, and neuronal apoptosis was measured by terminal deoxynucleotidyl transferase mediated dUTP biotin nick end labeling (TUNEL) staining.


RESULTS
The brain water content and the number of apoptotic cells were significantly higher in the HIBD group than those of the Control group (P < 0.05). Both baicalin and Dex pretreatment decreased the brain water content from 88.9 +/- 1.7 % (HIBD group) to 87.4 +/- 0.7% (baicalin) or 87.3 +/- 0.6% (Dex) (P < 0.05) and the number of apoptotic cells were reduced from 251 +/- 28 (HIBD group) to 102 +/- 47 (baicalin) or 75 +/- 26 (Dex) (P < 0.05). Baicalin and Dex post-treatment had no effects on the brain water content and the number of apoptotic cells. Loss and degeneration of neurons could be observed in the HIBD group. Baicalin and Dex pretreatment significantly alleviated neuronal injury, but post-treatment did not.


CONCLUSIONS
Pretreatment with baicalin, as with Dex, has a protective effect against HIBD in neonatal rats, but baicalin or Dex post-treatment do not reverse the neuronal injuries.
Lin
Xiao-Juan
XJ
Department of Pediatrics, People's Hospital of Hunan Province, Changsha 410008, China.
Yang
Yu-Jia
YJ
Qi
Bo-Xiang
BX
Wang
Xia
X
Song
Jian-Hui
JH
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001834:Body Water / Q000378:metabolism; D001921:Brain / Q000378:metabolism / Q000473:pathology; D005260:Female; D005419:Flavonoids / Q000627:therapeutic use*; D020925:Hypoxia-Ischemia, Brain / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D020287:In Situ Nick-End Labeling; D008297:Male; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley
D005419:Flavonoids; D018696:Neuroprotective Agents; C038044:baicalin