Purpose: Our previous studies demonstrated that qijudihuangtang, a compound of traditional Chinese medicine, protects from MNU (N-methy-N-nitrosourea)-induced rat retina photoreceptor injury. The current study was aimed to investigate protective effect of qijudihuangtang on the gene expression of retina in the same model.
Methods: Thirty 46-day-old female Sprague-Dawley rats were randomly divided into three groups (each group, n=10). The rats received a daily intragastric administration of qijudihuangtang in drug group, and 0.9% NaCl in model and normal groups for 4 days. On the fifth day, the rats in model and drug groups received a single intraperitoneal injection of 40 mg/kg body weight of N-methy-N-nitrosourea (MNU). Equivalent volume of 0.9% NaCl was injected to the rats of normal group. After 12 h of injection, all animals were sacrificed. Fresh retinas were used to extract total RNA, which was assayed by microarray and real time RT-PCR. The differentially expressed genes were also analyzed for the functional annotation and signal network mapping.
Results: There were 75 and 118 genes differently expressed (ratio > or = 2.0) in model group versus normal group and model group versus drug group, respectively. The former mainly included genes upregulated and the latter included most genes downregulated. These genes were mainly assigned to the categories binding transcription factor, signaling molecular, receptor, nucleic binding and extracellular matrix, and involved biological processes including signal transduction, development, immune and defense, apoptosis. The differential expressed genes contributed to MAPK signaling pathways, Toll-like receptor signaling pathway and apoptosis pathway.
Conclusion: The gene expression in the early stage of MNU-induced rat retinal degeneration can be regulated significantly by the administration of qijudihuangtang. These changed genes were associated with specific functional groups.