Preparation Of Thermosensitive Keratin Gel And Its Treatment Of Intracerebral Hemorrhage Postoperative Iron Overload

In the previous study,it was found that the(kerateine,KTN)gel of the iron-loaded chelating agent was injected in situ to remove iron ions from the damaged area and reduce brain damage.However,the injectability of KTN gel is unsatisfactory,which affects the use and therapeutic effects of intracerebral hemorrhage.In this paper,the thermosensitive keratin gel(TKG)was synthesized by thiol click reaction to improve the injectability of the gel,the convenience of use and the compliance of patients.Meanwhile,TKG has better adaptability to irregular hematoma cavity filling due to sol-gel transformation,which is expected to improve the adsorption effect of iron ions,further reduce the secondary brain injury after intracerebral hemorrhage,and improve its surgical prognosis.The specific research content of this paper is as follows:(1)TKG was synthesized by a thiol click reaction.Four different grafting rates of TKG(TKG1,TKG2,TKG3 and TKG4)were synthesized by adjusting the ratio of KTN and monomeric N-isopropylacrylamide(NIPAm).The results of FT-IR and HNMR showed that KTN was grafted successfully with PNIPAm.The gelation study and DSC results showed that the gel had temperature sensitivity and the phase transition temperature was about 31°C.Meanwhile,the gelation and differential scanning calorimeter(DSC)results showed that the gel had temperature sensitivity,and the phase transition temperature was about 31oC.Meanwhile,rheological studies showed that the viscoelasticity of TKG with different graft rates was different,and the elastic modulus of TKG3 was about 450 Pa,which was similar to the mechanical properties of brain tissue.In addition,scanning electron microscope(SEM)shows that the synthesized TKG shows an interconnected three-dimensional porous structure,and the irregular cavity filling experiment shows that TKG has better cavity filling adaptability compared with KTN gel.(2)The effects of TKG with different grafting rates on iron ion removal and drug release in vitro were studied.The results show that TKG has good adsorption properties for iron ions in artificial cerebrospinal fluid.Within the first 10 min,TKG3 showed a better iron ion adsorption effect,the adsorption rate reached 7.43 ± 0.37 mg/g,and the iron ion concentration in artificial cerebrospinal fluid decreased to 52.59 ± 2.61 g/mL,and the clearance rate reached 52.19 ± 2.37%.Between 10 min and 210 min,the adsorption rate of the gel becomes slow and almost reaches the maximum value at 210 min,and then the iron ion adsorption basically reaches equilibrium.In vitro drug release showed that TKG had a favorable drug release effect,and deferoxamine mesylate(DFO)had a release rate of about 85% within 24 h.(3)The intracerebral hemorrhage model of rats was established by injecting autologous blood to induce hemorrhage,and the effect of dfo-loaded TKG in the treatment of iron overload was evaluated by investigating iron deposition,reactive oxygen species(ROS)content,cerebral edema and other indicators.The results showed that iron deposition and non-heme iron content increased after intracerebral hemorrhage,and the iron ion deposition was reduced by intraperitoneal injection and TKG drug in situ injection.Meanwhile,the in situ drug-loaded gel group showed a stronger iron overload elimination effect,and the in-situ drug delivery group used less,which is expected to reduce the toxic side effects of drugs.By measuring the ROS fluorescence intensity and brain water content in brain tissue,it was found that the in-situ gel group could better reduce the ROS and brain edema content in brain tissue.(4)The biocompatibility and biodegradability of TKG gel were investigated by injecting TKG gel into the brain of Sprague-Dawley(SD)rats.The results showed that the degradation rate of TKG reached 85% after 4 weeks of implantation in the brain.No acute toxicity was found after TKG was implanted into the brain during the experimental period,and the level of inflammatory factors did not increase significantly.However,no obvious pathological changes were observed by tissue section staining,indicating that TKG has good degradability and biocompatibility in the brainIn summary,compared with KTN gel,TKG has stronger injectability,iron ion scavenging effect,irregular cavity adaptability,good in vivo degradation and biocompatibility,which is expected to further improve the prognosis of intracerebral hemorrhage surgery.