Syndecan-1 As a Potential Messenger of Remote Postconditioning Effects in Experiments with Brain Ischemia

The mechanisms of cerebral ischemia–reperfusion injury (IRI)limitation by remote ischemic postconditioning (RPC) are of interestbecause the latter may positively influence functional recovery aftercerebral ischemia. The study was aimed to assess the role of plasmaproteins syndecan-1 (SDC-1) and annexin-5 (ANXA-5) in limiting cerebralIRI by RPC in a middle cerebral artery occlusion (MCAO) model inmale Wistar rats. The animals were randomized into three groups:(1) control sham-operated rats (SO group), (2) rats with 30-minMCAO-induced ischemia (MCAO group), (3) rats with 30-min MCAO-inducedischemia followed by RPC (MCAO + RPC group). SDC-1 plasma levels,as assessed by ELISA, in MCAO (41.4 ± 1.3 ng/mL) and MCAO + RPC(67.8 ± 5.8 ng/mL) rats were, respectively, by 30% (p < 0.05) and 112% (p < 0.01) higher than in SO control(31.9 ± 1.1 ng/mL). No intergroup differences in ANXA-5 plasma levelswere detected. Cerebral infarct volume in MCAO and MCAO + RPC ratsaccounted for 32.0 ± 2.5 and 13.6 ± 1.3% of the total brain volume,respectively (p < 0.05).Cerebral edema volume in MCAO and MCAO + RPC rats were 47.0 ± 3.3and 16.0 ± 2.1%, respectively (p <0.05). In MCAO + RPC animals, correlation analysis revealed a highdirect correlation between infarct size and right forelimb muscularstrength (grip strength test, 3.9 ± 0.8 H, p >0.5; KK = 0.72, p < 0.05) and a very high inversecorrelation between infarct size and right hindlimb capillary blood flow(Doppler flowmetry, r = –0.98, p < 0.01). Animals’ neurologicdeficits were assessed by the Garcia scoring scale, while theirlocomotor coordination was assessed in the Rotarod test. It is assumedthat SDC-1 plasma protein may serve as a potential regulator ofthe infarct size-limiting effect of remote ischemic postconditioning,which is determinative for functional recovery.