alpha-chymotrypsin and Reperfusion-Injury

Functional as well as structural reorganization of brain tissues takes place in the surrounding and remotes brain areas after focal ischemic lesions. In particular, reactive or regenerative processes have been described to occur in the infarction areas and the contralateral hemisphere. Experiments were performed on 63 rats, divided into 3 groups (each consisted of 21 animals): sham operated, short-term occlusion of the right middle cerebral artery (MCAO) group, and long-term MCAO group. We have studied changes in proteasome proteolysis during transient occlusion of the middle cerebral artery using method of Koizumi J., duration 2 and 60 min and made the comparison between changes in different types of proteasome activity and severity of ischemic injury and showed three types of decrease inproteolytic activity (trypsin-, chymotrypsin-like, peptidylglutamyl peptide-hydrolyzing) in the brain tissues. Chymotrypsin-like activity of ischemic areas of the brain for short-term MCAO decreased 4.1 times compared with controls (P > 0.05), for long-term MCAO decreased 5.8 times compared with controls (P < 0.05). Trypsin-like activity of ischemic areas of brain for short-term MCAO decreased 7.1 times compared with controls (P > 0.05), for long-term MCAO decreased 12.5 times compared with controls (P < 0.05). PGPH activity of ischemic areas for short-term MCAO decreased 8 times compared with controls (P > 0.05), for long-term MCAO decreased 2.8 times compared with controls (P < 0.05). The similar dynamics was observed also in the penumbra and the core zone of the brain at 6 h of reperfusion, in the long run there is no significant difference between the core and contralateral zones. Our results suggest that proteasome activity may play also a role in contralateral cortical plasticity occurring after focal cerebral ischemia.

Topics: Animals; Brain; Brain Chemistry; Brain Ischemia; Cerebral Arteries; Chymotrypsin; Endopeptidases; Male; Proteasome Endopeptidase Complex; Proteolysis; Rats; Rats, Wistar; Reperfusion Injury; Stroke; Trypsin

To evaluate the protective effects of bortezomib (Velcade) on ischemia-reperfusion (IR) injury in the rat retina.. The rats were randomized to receive treatment with saline, low-dose bortezomib (0.05 mg/kg), or high-dose bortezomib (0.2 mg/kg) before the induction of IR injury. Electroretinography (ERG) was used to assess functional changes in the retina. The expression of inflammatory mediators (iNOS, ICAM-1, MCP-1, TNF-α), anti-oxidant proteins (heme oxygenase, thioredoxin, peroxiredoxin), and pro-apoptotic proteins (p53, bax) were quantified by PCR and western blot analysis. An immunofluorescence study was performed to detect the expression of iNOS, oxidative markers (nitrotyrosine, 8-OHdG, acrolein), NF-κB p65, and CD 68. Apoptosis of retinal cells was labeled with in situ TUNEL staining. Neu-N staining was performed in the flat-mounted retina to evaluate the density of retinal ganglion cells.. ERG showed a decreased b-wave after IR injury, and pretreatment with bortezomib, especially the high dosage, reduced the functional impairment. Bortezomib successfully reduced the elevation of inflammatory mediators, anti-oxidant proteins, pro-apoptotic proteins and oxidative markers after IR insult in a dose-dependent manner. In a similar fashion, NF-κB p65- and CD 68-positive cells were decreased by bortezomib treatment. Retinal cell apoptosis in each layer was attenuated by bortezomib. The retinal ganglion cell density was markedly decreased in the saline and low-dose bortezomib groups but was not significantly changed in the high-dose bortezomib group.. Bortezomib had a neuro-protective effect in retinal IR injury, possibly by inhibiting the activation of NF-κB related to IR insult and reducing the inflammatory signals and oxidative stress in the retina.

Topics: Animals; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Apoptosis; Apoptosis Regulatory Proteins; Biomarkers; Boronic Acids; Bortezomib; Cell Count; Chymotrypsin; Gene Expression Regulation; Inflammation Mediators; Male; NF-kappa B; Nitric Oxide Synthase Type II; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Pyrazines; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Retina; Retinal Ganglion Cells; RNA, Messenger

In this study we investigate the changes in intestinal motor responsiveness after mild mesenteric ischemia/reperfusion in anaesthetized rats. Motor responsiveness to pharmacological/electrical stimulation was studied in isolated ileum excised from sham-operated rats or animals which underwent occlusion of superior mesenteric artery (1 h) plus interruption of collateral blood flow and reperfusion for 0, 24, 72 h. Only 24 h reperfusion resulted in a significant suppression in acetylcholine induced contractile response and in indomethacin induced relaxation. In the presence of adrenergic and cholinergic blockade a greater relaxant response to field stimulation (trains 10 s every min, 120 mA, 1 ms and 10 Hz) was unmasked in all groups except 24 h reperfused rats. Such effect was sensitive to N(G)-Nitro-L-arginine methyl ester (NOS unselective inhibitor) and the proteolytic enzyme alpha-chymotrypsin but resistant to aminoguanidine (iNOS selective inhibitor). In conclusion, in this rat model, intestinal mild ischemia/24 h reperfusion induces reversible changes in enteric motility attributable to a decrease in eicosanoids, nitric oxide and neuropeptides availability.

Topics: Acetylcholine; Animals; Chymotrypsin; Disease Models, Animal; Dose-Response Relationship, Drug; Electric Stimulation; Gastrointestinal Motility; Ileum; In Vitro Techniques; Indomethacin; Intestinal Mucosa; Male; Mesenteric Arteries; Mesenteric Vascular Occlusion; Muscle Contraction; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase; Nitric Oxide Synthase Type III; Rats; Rats, Wistar; Reperfusion Injury