Effects of astragalan on neurotransmitters and expression of c-fos mRNA in hippocampus after ischemic brain injury in rats

AIM: To explore the effects of astragalan (AG) on the neurotransmitters,acetylcholine (ACh), norepinephrine (NE) and 5-hydroxytryptamine (5-HT), and the expression of c-fos mRNA in hippocampus after ischemic brain injury in rats. METHODS: Male Wistar rats (180~220 g) were randomly divided into 10 groups (n=10): sham-operated group (SOG), 3 model groups (MG 1 d, 3 d, 7 d) and 3 low- or high-dose AG treatment groups (L/H-AGTG 1 d, 3 d, 7 d), respectively. The middle cerebral artery of the rats in MG group and AGTG group were blocked by operation to induced brain injury. The cerebral blood vessels of the animals were blocked on day 1, day 2 and day 7, respectively, after the L/H-AGTG were treated with AG (5 mg/kg and 15 mg/kg, ip). The content of ACh,5-HT and NE was determined using their respective ELISA kits, and the expression of c-fos mRNA in the hippocampus homogenate was semiquantitative analyzed by RT-PCR after neurologic impairment (NIP) was scored. RESULTS: AG attenuated the injury in hippocampus by cerebral ischemia in a dose-dependent manner. The content of ACh, 5-HT and NE in L-AGTG 7 d,H-AGTG 3 d and 7 d groups was significantly higher than that in MG group, but was lower in SOG group (P<0.05 or P<0.01). The mRNA expression of c-fos in SOG group was lower than that in MG group (P<0.05 or P<0.01), indicating that reinforcement expression of c-fos mRNA by cerebral ischemia and the expression of downstream genes may be beneficial for protecting the neurons. The mRNA expression of c-fos in H-AGTG 3 d/7 d groups was higher than that in MG group (P<0.05). CONCLUSION: AG attenuates the damage of neurons and improves the functions of hippocampus under the condition of cerebral ischemia/reperfusion by increasing the content of ACh, NA and 5-HT, and the mRNA expression of c-fos in hippocampus.