Efficacy of brain-targeted rapamycin for treatment of epilepsy in rats / 浙江大学学报·医学版

OBJECTIVE@#To investigate the efficacy of brain-targeted rapamycin (T-Rap) in treatment of epilepsy in rats.@*METHODS@#Rapamycin nanoparticles targeting brain were prepared. The epilepsy model was induced by injection of pilocarpine in rats. The rats with pilocarpine-induced epilepsy were treated with rapamycin (Rap group) or brain-targeted rapamycin (T-Rap group). Seizure activity was observed by electroencephalography; the effect on mTOR signaling pathway was detected by Western blot; neuronal death and moss fiber sprouting were analyzed by Fluoro-Jade B (FJB) and Timm's staining, respectively.@*RESULTS@#Electroencephalography showed that both preparation of rapamycin significantly reduced the frequency of spontaneous seizures in rats, and the effect of T-Rap was stronger than that of conventional rapamycin (<0.05). Western blot showed that the phosphorylation levels of S6K and S6 in T-Rap group were lower than those in Rap group (all <0.05), indicating that T-Rap had a stronger inhibitory effect on mTOR signaling pathway. FJB staining showed that T-Rap significantly decreased neuronal death, but there was no significant difference as compared with Rap group. Timm's staining showed that both preparations of rapamycin significantly reduced the germination of mossy fibers, while the effect of T-Rap was more pronounced than Rap group (<0.05). The inhibition of body weight gain of T-Rap group was less than that of Rap group (<0.05).@*CONCLUSIONS@#T-Rap has a better therapeutic effect on epilepsy than conventional rapamycin with a less adverse effects in rats.

Inhibiting mammalian target of rapamycin signaling pathway improves cognitive function in mice with chronic cerebral ischemia / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of mammalian target of rapamycin(mTOR) inhibitor-rapamycin on cognitive function after chronic cerebral ischemia in mice and its molecular mechanism.</p><p><b>METHODS</b>The chronic cerebral ischemia model was induced by ligation of right common carotid artery (rUCCAO) in 6-week-old ICR mice. The expressions of mTOR, S6K, S6 and corresponding phosphorylated proteins were detected by Western blotting at different time interval (1 h, 3 h, 6 h, 24 h, 3 d, 7 d, 2 w, 4 w, 6 w) after rUCCAO to determine the changes of mTOR signaling pathway. Rapamycin was administrated i.p. at the dose of 3.0 mg/kg 24 h after rUCCAO. Fluoro Jade B staining was used to detect the apoptotic cells. The expressions of Beclin and LC3-Ⅱ were detected by Western blotting to determine the status of autophagy. Morris water maze test and Y maze test were performed to evaluate cognitive functions.</p><p><b>RESULTS</b>The mTOR signaling pathway was abnormally activated from 6 h to 6 w after rUCCAO in mouse cortex. The activation of mTOR signaling pathway induced by rUCCAO was reversed by administration of rapamycin, and the apoptotic cell number was significantly decreased (146.1±16.3 vs 84.5±9.6,<0.05). Meanwhile, the elevation of Beclin and LC3-Ⅱ protein induced by rUCCAO was reversed by rapamycin administration. Furthermore, compared with vehicle-treated mice, the latent period[(11.1±2.3) s vs (8.1±1.8) s,<0.05] and swimming distance[(672.8±128.5) cm vs (558.2±124.9) cm,<0.05] were significantly decreased and the number of crossing the platform quadrant in Morris water maze increased(2.8±0.9 vs 5.2±0.8,<0.05) in rapamycin-treated mice. Correct response rate in the Y maze was also increased significantly in rapamycin-treated mice[(38.5±9.2)% vs (64.9±7.9)%,<0.05].</p><p><b>CONCLUSIONS</b>Inhibiting mTOR pathway by rapamycin reverses the rUCCAO-induced cognitive impairment partly through the suppression of apoptosis and autophagy.</p>