Insulin-like growth factor-1 improves postoperative cognitive dysfunction following splenectomy in aged rats

Figures

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  Figure 1. Neurocognitive tests were performed using the Morris water maze. The results revealed that (A) Swimming distance and (B) Escape latency increased in the S, S + NS and S + IGF-1 groups compared with the C and I groups at days 1, 3 and 7 post-surgery. #P<0.05 vs. C and &P<0.05 vs. I. *P<0.05 vs. S and $P<0.05 vs. S + NS. C, control; I, isoflurane; S, splenectomy; NS, normal saline; IGF-1, insulin-like growth factor-1.

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  Figure 2. Hippocampal levels of APP, BACE-1 and Aβ after splenectomy at different timepoints. (A) IGF reduces the levels of (B) APP, (C) BACE-1 and (D) Aβ in the hippocampus of aged rats at days 1, 3 and 7 post-surgery. #P<0.05 vs. C and &P<0.05 vs. I. *P<0.05 vs. S and $P<0.05 vs. S + NS. IGF-1, insulin-like growth factor-1; APP, amyloid precursor protein; BACE-1, β-site APP-cleaving enzyme-1; Aβ, amyloid-β; C, control; I, isoflurane; S, splenectomy; NS, normal saline.

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  Figure 3. Hippocampal levels of caspase-3, Bax and Bcl-2 after splenectomy at different timepoints. (A) IGF reduces the expression amounts of (B) caspase-3, (C) Bax and (D) Bcl-2 in the hippocampal samples of aged rats at days 1, 3 and 7 post-surgery. #P<0.05 vs. C and &P<0.05 vs. I. *P<0.05 vs. S and $P<0.05 vs. S + NS. IGF-1, insulin-like growth factor-1; C, control; I, isoflurane; S, splenectomy; NS, normal saline.

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  Figure 4. TUNEL staining results of the hippocampal CA1 region of rats. The numbers of neurons were reduced in the C and I groups. Markedly increased numbers of apoptotic neurons and neuron shrinking were observed in S and S + NS groups. The number of apoptotic neurons markedly decreased in the S + IGF-1 group compared with the S and S + NS groups. Black arrows indicate apoptotic neurons. Scale bar, 50 µm. C, control; I, isoflurane; S, splenectomy; NS, normal saline; IGF-1, insulin-like growth factor-1.