Anti-Epileptic Effects Of Ghrelin And Its Possible Mechanisms

Objective:The relationship between Ghrelin and seizures was investigated in epileptic patients.The possible mechanism of Ghrelin's anti-epileptic effect and dose-dependent anti-oxidation effect was explored in terms of behavioral,inmmunohistochemistry and histopathology in PTZ-induced generalized tonic-clonic seizure rats.The results will provide important evidence and potential biomarker for epilepsy's diagnosis and treatment.Methods:Part ?: 20 patients with epileptic seizures(including comprehensive seizures and partial seizures)within 24 hours were selected as epilepsy group,and 20 healthy subjects were selected as normal control group.Serum Ghrelin levels were measured by enzyme-linked immunosorbent assay(ELISA);clinical data were collected.General clinical characteristics included age?gender and etc.and statistically compared with the normal control group.Part ?: 75 Wistar rats(weighting 180-200g)were randomly divided into 6 groups: 1.normal control group: 1 ml saline i.p.30 min before 1 ml saline i.p.;2.PTZ group: 1 ml saline i.p.30 min before PTZ(60mg/kg)i.p.;3.low-dose Ghrelin group: 30?g/kg Ghrelin i.p.30 min before PTZ(60mg/kg)i.p.;4.medium-dose Ghrelin group: 50?g/kg Ghrelin i.p.30 min before PTZ(60mg/kg)i.p.;5.high-dose Ghrelin group: 80?g/kg Ghrelin i.p.30 min before PTZ(60mg/kg)i.p.;6.very high-dose Ghrelin group: 100?g/kg Ghrelin i.p.30 min before PTZ(60mg/kg)i.p..The severity of seizures and seizure duration in rats were observed and recorded.The survival of neurons in hippocampal CA1 area and serum oxidative stress levels(including CAT,GSH,MDA,T-AOC)were measured.Results:1.PTZ group observed epilepsy after a single injection of PTZ at a dose of 60mg/kg,including hyperactivity,convulsions,excessive limb extension and general rigidity-clonic convulsions.All PTZ-induced epilepsy model of generalized tonic-clonic seizures in Wistar rats was successfully established.2.Intervention with different doses of Ghrelin(30,50,80,and 100?g/kg)30 minutes prior to PTZ injection significantly prolonged the seizure onset(ST1),tail extension(ST3),and reduced the incidence of general tonic-clonics(p<0.05).3.The middle,high,and very high Ghrelin group(50,80,and 100?g/kg)significantly prolonged the generalized tonic-clonic seizure time(ST4)(p<0.05);the low dose Ghrelin group(30?g/kg)extended ST4 was not statistically significant(p>0.05).4.Serum MDA levels were elevated in PTZ-induced epilepsy rats compared with normal controls,and Ghrelin at doses of 30 to 100?g/kg significantly down-regulated these increases(p< 0.05).5.The serum levels of CAT and GSH were significantly decreased in PTZ-induced seizure rats(p<0.05),and serum anti-oxidation levels were increased in a dose-dependent manner after prior intervention with different doses of Ghrelin(CAT: r=0.575,p<0.01;GSH: r=0.509,p<0.01).6.Serum MDA levels were elevated in PTZ-induced seizure rats(p<0.05)and strongly negatively correlated with dose-dependent Ghrelin treatment(MDA: r =-0.620,p< 0.01).7.Serum T-AOC level was significantly lower in the PTZ group compared with the control group,and Ghrelin prior intervention up-regulated PTZ-induced reduction of total serum antioxidant capacity(p<0.05);A weak correlation was observed between total antioxidant capacity and dose-dependent Ghrelin interventions(T-AOC: r=0.335,p<0.01).8.Compared with the control group,the low-dose Ghrelin group(30?g/kg)decreased levels of MDA and CAT,but there was no statistical difference(p>0.05).9.Compared with the normal control group,the serum Ghrelin level in the epilepsy group was slightly decreased,but there was no statistical difference(p>0.05).10.Nissl staining: In the normal control group,the neurons in the hippocampal CA1 area of are layered tightly and neatly arranged,the nucleus is round or elliptical,the cytoplasm is uniform,the Nissl bodies in the cytoplasm are abundant,and the cell morphology is clear and complete.In the PTZ group,the neurons were scattered,nuclear pyknosis,deep cytoplasmic staining,partial nuclear membrane damage,unclear cell contour.In Ghrelin pre-treatment group,the neurons was neatly arranged,and the degenerated and dead neurons were reduced,compared to the PTZ group.Conclusions:1.Ghrelin has anti-epileptic effect in PTZ-induced generalized tonic-clonic epilepic rat models.2.Ghrelin has a protective effect on PTZ-induced oxidative stress.3.Ghrelin may present its anti-epileptic effect by increasing the level of anti-oxidation and reducing lipid peroxidation,and this anti-oxidation effect has a dose-dependent effect.4.Ghrelin has a neuroprotective effect on hippocampal CA1 neurons in PTZ-induced epilepic rats.