| ObjectiveThe aim of this study was to explore the effects of TGN-020(2-(Nicotinamide)-1,3,4-thiadiazole)as a specific inhibitor of aquaporin 4(AQP4)on secondary edema,astrocyte proliferation,glial scar formation and axonal regeneration after spinal cord injury(SCI)in rats and to provide a important basis for the study of the relationship between edema and astrocyte proliferation,as well as the clinical treatment of SCI.Methods105 adult female SD rats(180-220g)were randomly chosen and divided into three groups(n=35)respectively,sham operation group(sham group),spinal cord injury group(SCI group),TGN-020 intervention group(TGN-020group).We used the modified compressive device with a sterile solid metal impounder with weight of 35 g and diameter of 2mm squeezing T10 Spinal Cord vertically to establish the moderate SCI model,the sham group underwent lamnectomy without injurying the spinal cord.TGN-020 group received TGN-020(100mg/kg,ip),0.1% DMSO(Dimethyl Sulfoxid)which was the same volume with the TGN-020 group was injected to the SCI group and the sham group via intraperitoneal injection postoperatively.Neurological function was evaluated using the Basso-Beattie-Bresnahan open-field locomotor scale at 1,3,7,14,21,and 28 days after SCI.The degree of edema was assessed via determination of the precise spinal cord water content 3 days after SCI.Expression levels of AQP4,glial fibrillary acidic protein(GFAP),proliferating cellnuclear antigen(PCNA),and growth-associated protein-43(GAP-43)were determined via western blotting and immunofluorescence staining 3 days after SCI and 4 weeks after SCI.Numbers of surviving neurons and glial scar sizes were determined using Nissl and hematoxylin-eosin(HE)staining 4 weeks after SCI,respectively.ResultsBBB scores in the TGN-020-treated group were significantly higher than those of the SCI group from day 3 to day 28 after SCI(p<0.01 for day 7;p<0.05 for days 3,14,21,and 28).At day 3,the water content in the injured area of spinal cord in SCI group and TGN-020 group was significantly higher than the sham group(p<0.01),and that water content in TGN-020 group was significiantly lower than the SCI group(p<0.05).Compared with the sham group,AQP4 expression was significantly increased 3 days after compression injury in the SCI group(p<0.01)and in the TGN-020 group(p<0.05),in the TGN-020 group,AQP4 expression was significantly lower than it was in the SCI group(p<0.05);Compared with the sham group there were significant increases in the expression of GFAP and PCNA in the SCI group and the TGN-020 group(p<0.01),GFAP and PCNA expression were significantly lower in the TGN-020 group than they were in the SCI group(p<0.05)3 days after SCI.At 4 week,compared with the sham group,GAP-43 expression was significantly upregulated in the SCI group(p<0.01),in the TGN-020 group,GAP-43 expression was greater than it was in the SCI group(p<0.05).HE staining showed that the size of glial scar in TGN-020 group was significantly smaller than that in SCI group(p<0.01).and nissl staining showed that the number of surviving neurons in TGN-020 group was significantly higher than that in SCI group(p<0.01)at 4 weeks after SCI.ConclusionsTGN-020 can alleviate the degree of edema after spinal cord injury,inhibitastrocyte proliferation and glial scar formation,promote the survival of neurons and regeneration of axons,further to promote the recovery of motor function after SCI in rats. |
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