Experimental Study On The Effect Of Estrogen Levels Change On The Structure Of Rats’ Condyle

[Objective]:Idiopathic condylar resorption(ICR)is a kind of rare bone resorption disease,showing a progressive development,which often occurs in the adolescent females.Female patients with the disease can exclude various diseases that can cause ICR,but the estrogen level in the body is lower.Further examination often shows that the female patients suffer from the premature ovarian failure or a long-time administration of oral contraceptive,Therefore,we hypothesized that estrogen may have a close relationship with ICR.To explore the specific association between estrogen and ICR;To provide reliable clinical basis for the diagnosis and treatment of ICR,This study intends to establish the ICR animal model.And then the estrogen was supplemented,the changes in condylar before and after treatment were observed and measured.To explore the feasibility of estrogen for ICR treatment [Methods]:40 unmated female SD rats with 6-week-old、in SPF-level、normal estrous cycle,randomly divided into three groups: Group A and B(n=15)(the rats might die after intraperitoneal injection of cisplatin,so 10 surviving rats were randomly selected into the result analysis)and Group C(n=10)for experiment.The group is divided as follows:Group A: cisplatin group(ICR group): 1 times weekly intraperitoneal injection of cisplatin(6.0mg/kg),injected for 2 weeks.Destroy the normal secretion of estrogen in the ovary,resulting in lower estrogen levels in the body and establish ICR animal model;Group B: cisplatin + estradiol group(estrogen treatment group): 1 times weekly intraperitoneal injection of cisplatin(6.0mg/kg),injected for 2 weeks.Destroy the normal secretion of estrogen in the ovary,resulting in lower estrogen levels in the body and establish ICR animal model.At 30 d,the estradiol valerate(0.105mg/kg)was administrated via gastrointestinal tract every day,lasts 30 days;Group C: blank control group: free diet without any treatment.Serum estradiol concentration was detected before the experiment,at 7d,30 d and 60 d of experiment.Five rats were executed at 28 d and 60 d of experiment,respectively.The condylar process was made into the section,followed by HE staining and observation of condylar cartilage morphology.[Results]:(1)Serum E2 concentration measurement:I: At 7d and 28 d of experiment,the serum E2 concentration in cisplatin group and cisplatin + estradiol group was significantly decreased compared with that in control group,and the difference was statistically significant(P<0.05).II: At 60 d,the serum E2 concentration in cisplatin + estradiol group was significantly increased compared with that in cisplatin group,and the difference was statistically significant(P<0.05).(2)HE-staining of condylar cartilage:I: Compared with that in control group,the condylar cartilage structure of cisplatin group and cisplatin + estradiol group was changed,showing the degenerative change,the cartilage thickness was decreased,the cell arrangement was disordered,the number of trabecular bone was reduced and the structure was loose.II: Compared with that in cisplatin group,the thickness of condylar cartilage of cisplatin + estradiol group was increased,the number of trabecular bone increases,showing the reparative change.[conclusion]:Under the environmental conditions of this experiment1: Intraperitoneal injection of cisplatin can disrupt the normal secretion of estrogen in the ovary,the serum E2 concentration in rats was obviously decreased,cause ICR,the condylar cartilage thickness,cell structure disorder,degenerative changes.2: the administration of estradiol valerate via gastrointestinal tract can increase the serum E2 concentration in rats and thickness of condylar cartilage with reparative changes.Thus,the degenerative changes of the condyle can be improved and the progression of ICR can be slowed down.