性别对L-精氨酸诱发的昆明小鼠慢性胰腺炎的影响

摘要

目的:通过比较雌雄小鼠L-精氨酸诱发的慢性胰腺炎(CP)程度的差异,探讨性别对CP模型形成的影响.方法:健康昆明小鼠雌雄各42只,分为雌性对照组、雌性CP组、雄性对照组和雄性CP组(对照组n=18,每时点6只;CP组n=24,每时点8只).CP模型组小鼠腹腔注射20% L-精氨酸(3 g/kg,每周1次,每次2轮,间隔1 h)诱发CP.分别于造模后第2、4、6周处死动物,取小鼠胰腺组织,HE及Masson染色检测各组小鼠胰腺形态学改变及纤维化程度;免疫组织化学观察胰腺组织F4/80的阳性染色率;real-time PCR检测胰腺组织白细胞介素6 (interleukin-6,IL-6)、α-平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)及纤维连接蛋白(fibronectin,FN)的mRNA表达;Western blot检测胰腺组织α-SMA及FN蛋白的表达.结果:20%L-精氨酸腹腔注射后的第2、4和6周,HE及Masson染色显示雌雄CP组胰腺组织均可见病理损伤,但是同一时点雌雄小鼠胰腺损伤程度存在明显差异,雄性小鼠胰腺病变程度明显较重;胰腺F4/80染色显示雄性小鼠胰腺F4/80的表达水平在造模后各时点均明显高于同一时点的雌性小鼠;造模后第2和4周胰腺IL-6的mRNA表达在雌雄CP组均有所升高,但是雄性组表达水平明显高于雌性组(P<0.05).造模后α-SMA和FN在mRNA水平和蛋白质水平均可见高表达,但雄性小鼠表达时点更早,水平更高(P<0.05).结论:采用腹腔注射20%L-精氨酸可成功复制小鼠CP模型,但复制的模型在雌雄小鼠存在病变程度差异.L-精氨酸诱导的CP模型在雄性小鼠成模更早、纤维化程度更明显,其原因可能与雄性小鼠对L-精氨酸更敏感,引发的炎症反应程度更明显有关.雄性小鼠更适合于复制CP动物模型.%AIM:To explore the effect of sex on the formation of chronic pancreatitis(CP)by comparing the differences in L-arginine-induced CP model between male and female mice.METHODS:Male(n=42)and female(n=42)Kunming mice were randomly divided into 4 groups:female control group, female CP group, male control group and male CP group(n=18 in each control group, n =6 at each time point; n=24 in each CP group, n=8 at each time point).The mice in CP groups were intraperitoneally injected with 20%L-arginine(3 g/kg,twice/d,1 d/week).After modeling for 2 weeks,4 weeks and 6 weeks,the mice were anesthetized and sacrificed.The morphological changes and the degree of fibrosis in the pancreas were observed by HE and Masson staining.The positive expression rate of F4/80 in the pancreatic tissues was observed by the method of immunohistochemistry.The mRNA expression of interleukin-6(IL-6), α-smooth muscle actin(α-SMA)and fibronectin(FN)in the pancreas were detected by real-time PCR.The protein of pancreas was extracted to detect the expression of α-SMA and FN by Western blot.RESULTS:At 2 weeks,4 weeks and 6 weeks after intraperitoneal injection of L-arginine, the pancreatic tissues were obviously injured and exhibited different degrees of fibrosis in female and male CP groups.At the same time,there were significant differences in the degree of pan-creatic injury between male and female mice,and the degree of pancreatic lesion in the male mice was significantly more severe.The positive rate of F4/80 in the pancreas of male CP mice was significantly higher than that in female CP group at the same time point after modeling.At every time point, the mRNA expression of IL-6 in the pancreas was increased in both female and male CP groups,but that in male CP group was higher(P<0.05).The fibrosis indexes,α-SMA and FN, were both highly expressed at mRNA and protein levels after modeling, but compared with the female group, the time of positive expression in male mice was earlier and the expression level was higher(P<0.05).CONCLUSION: The CP model is successfully established by intraperitoneal injection of 20%L-arginine,and a difference in the degree of pathologic alteration in pancreas between male and female mice exists.CP is more effectively induced by L-arginine in male mice,and the degree of fibrosis is more pronounced.The reason may be related to the sensitivity of male mice to L-arginine,causing more serious inflammatory response.Therefore,male mice are more suitable for establishing CP animal model.