雌激素对大鼠下颌髁突软骨、软骨下骨退行性变影响的研究

The effects of estrogen on the degenerative changes of rat condylar cartilage and subchondral bone

目的:探究雌激素对大鼠下颌髁突软骨、软骨下骨退行性变转归的影响。方法:6周龄雌性SD大鼠造单侧前牙反(UAC)模型,腹腔注射外源性17β-雌二醇80μg。4周后处死、取材。HE、番红-O-固绿、免疫组化、TUNEL、TRAP染色及microCT观察髁突软骨、软骨下骨的退变情况。结果:UAC模型造成了明显的软骨厚度降低,细胞外基质丢失,软骨细胞凋亡,软骨下骨吸收以及破骨细胞活动增强;而雌激素注射则加重了软骨的破坏但明显抑制了软骨下骨的吸收以及破骨细胞的活动。结论:在大鼠UAC致TMJOA模型中,外源性雌激素能逆转髁突软骨下骨的退行性变,但加重髁突软骨的退行性变。

Objective:To study the effects of estrogen on the degenerative changes of condylar cartilage and subchondral bone in rats. Methods:18female SD rats aged6weeks were divided into control(C),unilateral anterior cross-bite(UAC)and UAC treated with estrogen(UAC+E)groups(n=6).UAC metal prosthesis was cemented to the left incisors of maxilla and mandible of the rats in group UAC and UAC+E.Rats in UAC+E group were given pexitoneal injection of80μg17β-estradiol per day.The rats in group C were untreated.Animal were sacrificed at the4th weeks.The micro-structure of subchondral bone was observed by Micro-CT scanning.HE staining,Safranin O staining,immunohistochemieal staining,TUNEL staining and TRAP staining for the observation of pathological changes of histomorphology,extracellular matrix,chondrocyte apoptosis in condylar cartilage,and osteoclasts number in subchondral bone.Results:UAC and UAC+E group showed evident osteoarthritis(OA)-like lesions.Compare with UAC group,there was a significant decrease in the expression of proteoglycan(P<0.05),typeⅡcollagen(P<0.01),and a significant increase in the number of apoptotic chondrocytes(P<0.01)in UAC+E group.As for subchondral bone,the BV/TV,Tb.Th parameters in C and UAC+E groups were significant higher than in UAC group(P<0.01),while the BS/BV,Tb.N,Tb.Sp parameters and the osteoclasts number in C and UAC+E groups were significant fewer than in UAC groups(P<0.01).There was no significant difference in bone ultra-parameters and osteoclasts number between C and UAC+E groups(P>0.05).Conclusion:In the model of rat TMJOA induced by unilateral anterior crossbite prosthesis,supra-physiological level of estrogen can reverse bone loss in subchondral bone,but accelerate the degradation of condylar cartilage.