n-(n-(3-5-difluorophenacetyl)alanyl)phenylglycine-tert-butyl-ester and Body-Weight

We studied the effects of minocycline (an inhibitor of microglial activation) on the expression and activity of Notch-1 receptor, and explored the therapeutic efficacy of minocycline combined with Notch inhibitor DAPT in the treatment of diabetic neuropathic pain (DNP). Diabetic rat model was established by intraperitoneal injection (ip) of Streptozotocin (STZ). Expression and activity of Notch-1 and expression of macrophage/microglia marker Iba-1 were detected by WB. Diabetes induction significantly attenuated sciatic nerve conduction velocity, and dramatically augmented the expression and the activity of Notch-1 in the lumbar enlargement of the spinal cord. Minocycline treatment, however, accelerated the decreased conduction velocity of sciatic nerve and suppressed Notch-1expression and activity in diabetic rats. Similar to DAPT treatment, minocycline administration also prolonged thermal withdrawal latency (TWL) and increase mechanical withdrawal threshold (MWT) in diabetic rats in response to heat or mechanical stimulation via inhibition the expression and the activity of Notch-1 in spinal cord. Combination of DAPT and minocycline further inhibited Notch-1 receptor signaling and reduce neuropathic pain exhibited as improved TWL and MWT. Our study revealed a novel mechanism of Notch-1 receptor inhibition in spinal cord induced by minocycline administration, and suggested that the combination of minocycline and DAPT has the potential to treat DNP.

Topics: Animals; Body Weight; Diabetic Neuropathies; Dipeptides; Glucose; Minocycline; Neural Conduction; Rats, Sprague-Dawley; Receptors, Notch; Signal Transduction; Spinal Cord; Sural Nerve

To investigate the effect of γ-secretase inhibitor (N-[N-(3,5-difluorophenacetyl)-l -alanyl]-S-phenylglycine t-butyl ester, DAPT) on hyperoxia-induced brain white matter injury in mice.. Three-day-old C57BL/10J mouse pups were divided into air control (C) group, control+DAPT (10 mg/kg, injected intraperitoneally) group, hyperoxia group (exposed to 80% oxygen for 48 h), and hyperoxia+DAPT group. The brain and body weights of the mice were measured at postnatal days 3, 5, 12, and 28. Real-time PCR was used to detect Notch intracellular domain (NICD) mRNA expression in the brain after modeling, and the expressions of NG2 and myelin basic protein (MBP) were detected by double-labeled immunofluorescence assay to verify the oligdendrocycle type at postnatal day 12. The mice in each group were bred until postnatal day 28 for Morris water maze test.. The brain and body weights were significantly decreased in mice in hyperoxia group compared to the control mice, but increased significantly after DAPT treatment (P<0.05). Real-time PCR showed that a 48-hour hyperoxia exposure significantly increased NICD mRNA expression in the brain (P<0.05), which was decreased by co-treatment by DAPT (P<0.05). Hyperoxia also resulted in enhanced NG2 expression and lowered MBP expression in the brain (P<0.05). Compared with the control mice, the mice exposed to hyperoxia showed prolonged escape latency (P<0.05) and spent less time in the target quadrant with a lowered number of passing through the virtual platform (P<0.05). All these parameters were significantly improved by co-treatment with DAPT.. Specific inhibition of Notch signaling pathway activation in the brain by the γ-secretase inhibitor DAPT can ameliorate white matter injury and learning and memory impairment in newborn mice with hyperoxia exposure.

Topics: Amyloid Precursor Protein Secretases; Animals; Body Weight; Brain; Dipeptides; Hyperoxia; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Organ Size; Receptors, Notch; Signal Transduction; White Matter