Experimental Study Of Chitosan Electrospun Membrane On Preventing Cerebrospinal Fluid Leakage

[Objective]1.To study the immediate prevention result of cerebrospinal fluid leakage by usingself-developed chitosan electrospun membrane.2. To study the long-term prevention effect ofcerebrospinal fluid leakage by using self-developed chitosan electrospun membranes.3. To studythe difference of normal dura mater and newly grown dura mater after complete repair of duraldefects with chitosan electrospun membrane.[Methods][1]. Took5healthy adult New Zealand rabbits, via midline incision of head, madecircular bone window, about1.2cm in diameter, in the bilateral parietal skull symmetrically. Cut0.8mm X0.8mm cerebral dura mater, put suitably sized chitosan electrospun membrane into theexperimental side of dural defect area; simultaneously, on the other side, only cut and not repairedcerebral dura mater as control group. Drill a small hole in the midline of skull, put a transparenttube through the hole into the subdural, saw cerebrospinal fluid reflux from the tube, and injectedmethylene blue solution slowly. Repeat for5times.[2]. Methods: Took40healthy adult NewZealand rabbits, via midline incision of head, made circular bone window, about1.2cm in diameter,in the bilateral parietal skull symmetrically. Cut0.8mmX0.8mm cerebral dura mater, put suitablysized chitosan electrospun membrane into the experimental side of dural defect area;simultaneously, on the other side, only cut and not repaired cerebral dura mater as control group.Sutured skin and subcutaneous, then feed the rabbits. Since t the second week, killed2of themevery week, observe the general situation surrounding bone window and chitosan membranes’absorption;postoperative3weeks,6weeks, killed5of them, observed gross around bone windows,histologic changes of wound, expression of vascular endothelial growth factor and basic fibroblastgrowth factor under microscope.[3]. Round bone windows (diameter=1.2cm) were operated onsixteen healthy adult New Zealand rabbits on bilateral sides symmetrically near the medial line. Thedura mater was removed0.8mm by0.8mm, where the chitosan electrospun membrane was placedin test group and the removed dura mater was sutured back in control group. Eight weeks (when thedura mater was considered reconstructed) after surgery, observation, histology test and electronmicroscopy were run to find the difference between the two groups.[Results]1.chitosan electrospun membrane adheres well to the wound and sealed the woundseffectively. After injecting methylene blue solution, no effusion happened on the experimental side, even there gathered a large number of methylene blue under the membrane, no solution exposedfrom the edge of film, while on the other side, the control group had methylene blue oozed all thetime.2.(1)、no inflammatory reaction like swelling、exudation、maturation appeared during skin andsubcutaneous after the operation; chitosan electrospun membrane was tightly wrapped; Cutwrapping tissue open from the midline incision, there was no adhesion around the member, and it’sgotten out easily; new fiber membrane formed under the member; no cerebrospinal fluid leakagehappened when closed the brain tissue tightly; no adhesions happened between new fibermembrane and brain tissue.(2)、HE stain showed less inflammatory cell infiltration in experimentalgroup compared with control group; Statistics show that three weeks and six weeks in theexperimental group were significantly different from the control group. capillary and granulationtissue hyperplasia was more than control group; large collagen fiber hyperplasia happened early inexperimental group, and tissue repair appeared earlier than control group.(3)、MASSON stainshowed there was large amount of fiber in experimental group, collagen fiber hyperplasia andarranged neatly, chitosan electrospun membrane and the surrounding collagen fibers have clearboundaries; While in control group there was less fiber, collagen fibers disordered with noregularity.(4)、immunohistochemical study showed there were high expression of bFGF and EGF,which means fibroblasts and endothelial cells were active, and low expression of bFGF and EGF.3.Postoperative observation showed no swelling, no bleeding, and no fester; and the chitosanmembrane was tightly wrapped with no adhesion and leakage. HE staining showed the new grownfiber membrane was mature with no bFGF nor EGF expression. Electron microscopy find that thereare plenty of collagen fibers and fibroblasts in the arranged in neat rows, the nucleus are mature, thenew fiber membrane is high similarity with the normal dura mater.[Conclusion]1.Chitosan membrane group was superior to the controls, the plugging effect oncerebrospinal fluid leakage can be determined.2. Chitosan membrane group was superior to thecontrol group, the long-term prevention effect on cerebrospinal fluid leakage can be determined.3.Chitosan membrane is effective in repairing dura mater, and the new fiber membrane ishistologically close normal meninges.