Experimental Study On The Gene Expression Of RANKL,OPG Of Alveolar Bone Of Diabetes Mellitus Rats

Objective: To investigate the mechanism of alveolar bone resorption of thosesuffering Diabetes mellitus(DM) and then clarify the relationship between DM andalveolar bone resorption through comparison of the level of Receptor activator ofnuclear factor-κB ligand (RANKL)mRNA and Osteoprotegerin (OPG)mRNAbetween normal rats, rats suffering DM and DM rats under cure by Isulin as well ashistology examination.Methods: Selected 18 male SD rats at 8 weeks old and divided them into 3groups at random which were NM group, DM group and INS group with 6 in eachgroup. As to DM group and INS group, DM model was established by injectingStreptozocin through caudal vein; then, injected hypodermically 6 U/(kg·d) Insulinof INS group and injected hypodermically saline with same quantity to DM groupand NM group. All rats were executed after 8 weeks. The alveolar bone of molarregion of the left jaw were choosen and apply the method of Reverse transcription-polymerase Chain raction (RT-PCR) to find out the expression of RANKL and OPGmRNA and compared difference of the ratio of RANKL to OPG of alveolar bonebetween 3 groups; The tissues of molar region of the right jaw were choosen andobserve the condition of periodontium by means of histology and count the quantityof Osteoclast. Record the concentration of blood glucose and the weight of each ratsbefore established DM model, after established DM model and before executedduring the experiment.Results:1. Conditions of blood glucose and weigh: Before established DM model, thedifference of the concentration of blood glucose and the weight between the threegroups were no statistically significant(P＞0.05); After established DM model,weigh of DM group is relative lower than that of NM group, there was asignificant difference between 2 groups(P＜0.05). The concentration of bloodglucose of DM group is relative higher than that of NM group, the difference hadobvious statistic significance(P＜0.01). Weigh of INS group is relative lower thanthat of NM group, there was a significant difference between 2 groups(P＜0.05).The concentration of blood glucose of INS group is relative higher than that of NMgroup, the difference had obvious statistic significance(P＜0.01).There were nostatistically significant between DM group and INS group on concentration of bloodglucose and weight. Before executed, weigh of DM group is lower than that of INSgroup, The concentration of blood glucose of DM group is higher than that of INSgroup, the difference had obvious statistic significance(P＜0.01), weigh of INSgroup is lower than that of NM group, The concentration of blood glucose of INS group is higher than that of NM group, the difference had obvious statisticsignificance(P＜0.01), weigh of DM group is lower than that of NM group, Theconcentration of blood glucose of DM group is higher than that of NM group, thedifference had obvious statistic significance(P＜0.01).2. Expression of RANKL and OPG mRNA of alveolar bone: Not all of theexpression of RANKL and OPG of alveolar bone among the three groups are of thesame. OPG of DM group is lower than that of INS group and NM group, thedifference had obvious statistic significance(P＜0.01). While the difference betweenOPG of INS with that of NM has no statistically significant(P＞0.05). RANKL ofDM group is higher than that of INS group and NM group and the difference hadobvious statistic significance(P＜0.01). While the difference between RANKL ofINS with that of NM has no statistically significant(P＞0.05).As to difference ofRANKL/OPG ratio, that of DM is higher than that of INS and NM and has obviousstatistic significance(P＜0.01).The ratio of RANKL/OPG of INS group is higherthan that of NM group, the difference had statistic significance(P＜0.05).3. Histological examination: Fracture of collagenous fiber of periodontalligament, inflammatory cells infiltrated,a great number of Osteoclast and boneresorption lacunae of alveolar bone were observed in DM group,only a fewinflammatory cells infiltrated and no active bone resorption were observed in INSgroup; no nflammatory cells infiltrated and no active bone resorption were observedin NM group.4. Osteoclast number: Not all of the Osteoclast number of the surface ofalveolar bone among the three groups are of the same. The quantity of osteoclast ofDM group is relative higher than that of INS group and NM group and thedifference had obvious statistic significance(P＜0.01). While the difference betweenINS group with that of NM has no statistically significant(P＞0.05).Conclusion:1. Rat DM model can be established by injecting Streptozocin throughcaudal vein.2. Suffer of DM would lower the expression of OPG mRNA and higher theexpression of RANKL mRNA of alveolar bone and increase the RANKL/OPGvalue, which increases the Osteoclast number of alveolar bone and enhance theabsorption risk of alveolar bone.3. It can reverse the change of expression of OPG mRNA and RANKL mRNAand make Osteoclast number of alveolar bone become normal during suffer of DMby decrease of blood sugar through injecting Insulin hypodermically. Thereby, it canrestrict absorption of alveolar bone when suffering DM.4. It is more sensitive to the change of RANKL/OPG value than the change the expression of OPG or RANKL respectively when suffering DM.5. There are close relations between DM and alveolar bone resorption.