Aim: To investigate the effect of tanshinone (Tan) on the neuropathological changes induced by amyloid beta-peptide1-40 (Abeta1-40) injection in hippocampus in rats.
Methods: Abeta1-40 10 microg was injected bilaterally into the dorsal blade of the dentate gyrus in the hippocampus. The level of acetylcholinesterase (AChE) in hippocampus was evaluated by histochemistry. The expressions of neuronal nitric oxide synthase (nNOS) and inducible form of NOS (iNOS) were detected by immunohistochemistry and Western blot. Abeta1-40-injected rats were treated ig with Tan, the major active ingredient from Salvia miltiorrhiza of Chinese herb extract.
Results: The level of AChE positive fibers of each subfield in Abeta1-40-injected hippocampus decreased significantly compared with those of control (P<0.01). The expression of nNOS was down-regulated whereas the iNOS was up-regulated. After treatment with Tan (50 mg/kg, ig), the changes mentioned above were significantly improved. Moreover, the correlation analysis revealed a significant negative correlation between the area percentage of AChE positive fibers and the number of iNOS positive neural cells in CA1, CA2 to CA3 (CA2-3), and dentate gyrus (DG) subfields (P<0.01).
Conclusion: Tan can protect the neuropathological changes induced by Abeta1-40 injection in hippocampus.