Effects of danshen and basic fibroblast growth factor on mRNA expression of inducible nitricoxide synthase mRNA in the brain of rats after repeated +Gz exposure

Hongjin LIU; Qing CAI; Jiandong JIANG; Zhi ZHAN; Meicai ZHU

ABSTRACT

BACKGROUND:

+Gz-induced acute dysencephalia and its protection is one of the significant topics in Aero-medical researches. Its pathological mechanism, however, is still unclear and protective measures should be developed further.

OBJECTIVE:

To observe the expression of inducible nitricoxide synthase (iNOS) in brain tissue after +Gz exposure and to analyze the protective effects of danshen and basic fibroblast growth factor (bFGF) on repeated +Gz exposure-induced brain injury.

DESIGN:

Randomized controlled animal study.

SETTING:

Researching Center of Molecular Biology, Air-force General Hospital of Chinese PLA.MATERIALS The experiment was carried out at the Researching Center of Molecular Biology, Air-force General Hospital of Chinese PLA from April to August 2000. A total of 20 healthy SD rats of clean grade were divided into 5 groups according to randomly digital table, including control group, +Gz exposure group, bFGF group, danshen group and saline group with 4 in each group.

METHODS:

All rats were fixed on rotatory arm of centrifugal apparatus,and their heads were towards core of the apparatus. Except the rats in control group, the value of +Gz exposure was +14 Gz, and the growth rate was 1.5 G/s. The exposure at peak value lasted for 45 s. +Gz exposure was done for three times, and the interval was 30 minutes. Rats in the control group were also treated with the same +Gz exposing procedure, but the G value was +1 Gz. Rats in bFGF group and danshen group were intraperitoneally injected with 100 μg/kg of bFGF and/or 15 g/kg of danshen solution, respectively, at 30 minutes before centrifugation and immediateness after centrifugation; moreover, rats in saline group were injected with the same volume of saline. Six hours after exposure, rats were cut off their heads to obtain the brains which were maintained in liquid nitrogen for RNA extraction. The expression of iNOS mRNA in brain tissues of the rats in each group was detected with semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and calculated on the basis of ratio between iNOS and glyceraldehyde-3-phosphate dehydrognase.MAIN OUTCOME

MEASURES:

Expressed level of iNOS mRNA in brain tissue of rats.

RESULTS:

Expression of iNOS mRNA in brain tissue was higher in repeated +Gz exposure group than that in control group (0.452 ±0.014,0.065±0.008, P ＜ 0.01); however, that was lower in bFGF group and dan-shen group than that in +Gz exposure group (0.196±0.010, 0.183±0.011,0.452±0.014, P ＜ 0.01).

CONCLUSION:

Repeated +Gz exposure can increase the expression of iNOS mRNA, this plays an important role in cerebral injury induced by repeated +Gz exposure. Moreover, bFGF and danshen have protective effects on cerebral injury induced by +Gz exposure.