Bone Marrow And None-bone Marrow Toll-like Receptor4Regulates Diabetic Retinopathy

Objective This study was to investigate the expression of bone marrow andnone-bone marrow derivted Toll-like receptor4(TLR4) in the diabetic retino and therole of them in diabetic retinopathy（DR）.Methods We used TLR4wild-type (C3H/HeN; WT) and mutant mice (C3H/HeJ;Mut) of12weeks of age, and established bone marrow transplanted chimeric mice inthe following donor/recipient groups: WT/Mut, Mut/WT, WT/WT and Mut/Mut, onemonth later, we duplicated DR model with STZ(200mg/Kg) injection. The normalmice was used to be control group：N. After the model establishment of one,two,fourmonth,we took samples.The retinal microvascular ultra-structure was observed undertransmission electron microscope；the expression of Intercellular adhesion molecule1(ICAM-1) was detected by immunohistochemistry；the expressions of TLR4andMacrophage inflammatory protein2(MIP-2)in the retina were detected by RT-PCR；the tumor necrosis factor a(TNF-a) and MIP-2in the blood serum were detected byELISA and the malonaldehyde（MDA）in the blood serum was also detected.Results After one month of the successfully establishment of the DR model, therewere obvious pathologic changes of the ganglionic and neurofibrous layer: pyknosisof nucleolus, edema of endochylema, and two month after the DR model created,there were damages in capillary endothelial cell: swelling and deformity ofmitochondria, shortening and disappearance of crista，between groups, the WT/WTwas the most severe, the Mut/Mut was the least severe, and the WT/Mut was moresevere than Mut/WT; Immunohistochemistry showed the expression of ICAM-1wasyellow in one month groups and brown in two month groups, the Mut/Mut groupexpressed weaker than the WT/WT group and the Mut/WT group expressed weaker than the WT/Mut group；RT-PCR showed that，the expression of MIP-2and TLR4inthe retina was up-regulated in the model groups with the course of DR，betweengroups, the order from high to low was: WT/WT, WT/Mut, Mut/WT and Mut/Mut（P<0.05）. ELISAshowed that the MIP-2、TNF-a and MDA in blood serum were toascend in the model groups with the course of DR, the order of the groups from highto low was: WT/WT, WT/Mut, Mut/WT, Mut/Mut（P<0.05）.Conclusion The retinal neuron damage is earlier than microvessel damage.；Themutation of TLR4reduce the pathologic damage of DR；Both bone marrow andnon-bone marrow TLR4have effects on DR；TLR4on bone marrow derived cells ismore important than non-bone marrow derived cells in the process of DR and themechanism is that the up-regluation of TLR4lead to the ascend of inflammatoryfactor.