CAJ | 학술논문

为了研究仔猪出生至断奶后肠道形态和相关免疫蛋白基因表达的变化,本试验于仔猪出生7、14和21 d以及断奶后14 d(出生35 d)分别从6窝中每窝挑选1头健康仔猪(共24头)屠宰获得十二指肠和空肠组织。利用苏木精-伊红染色检测小肠形态和淋巴细胞、杯状细胞计数,酶联免疫吸附法( ELISA)测定空肠组织中的分泌型免疫球蛋白A( sIgA)浓度,实时荧光定量PCR检测空肠组织中防御素基因的表达水平。结果表明：仔猪出生7~21 d,出生14和21 d的十二指肠和空肠的绒毛高度显著低于出生7 d(P<0.05),同时十二指肠的隐窝深度随着日龄的增加有逐渐降低的趋势,但肠上皮杯状细胞和淋巴细胞数目无显著变化(P>0.05)；断奶后14 d空肠绒毛高度较出生7 d显著降低(P<0.05),隐窝增生明显,隐窝深度较出生7~21 d显著增加(P<0.05),同时十二指肠和空肠上皮淋巴细胞数目均显著增多(P<0.05)。另外,较出生21 d,断奶后仔猪空肠分泌更多的sIgA(P=0.001)和表达更多的防御素基因(P<0.05)以保护肠黏膜。由此可知,断奶前,仔猪健康状况下肠道屏障完整,sIgA和防御素表达的水平相对较低,断奶破坏了肠道完整性,使得肠道绒毛萎缩,隐窝增生,肠道上皮屏障受到损伤,大量的淋巴细胞趋化至肠道上皮,同时断奶时微生物入侵刺激了肠上皮免疫球蛋白和防御素的分泌。
위료연구자저출생지단내후장도형태화상관면역단백기인표체적변화,본시험우자저출생7、14화21 d이급단내후14 d(출생35 d)분별종6와중매와도선1두건강자저(공24두)도재획득십이지장화공장조직。이용소목정-이홍염색검측소장형태화림파세포、배상세포계수,매련면역흡부법( ELISA)측정공장조직중적분비형면역구단백A( sIgA)농도,실시형광정량PCR검측공장조직중방어소기인적표체수평。결과표명：자저출생7~21 d,출생14화21 d적십이지장화공장적융모고도현저저우출생7 d(P<0.05),동시십이지장적은와심도수착일령적증가유축점강저적추세,단장상피배상세포화림파세포수목무현저변화(P>0.05)；단내후14 d공장융모고도교출생7 d현저강저(P<0.05),은와증생명현,은와심도교출생7~21 d현저증가(P<0.05),동시십이지장화공장상피림파세포수목균현저증다(P<0.05)。령외,교출생21 d,단내후자저공장분비경다적sIgA(P=0.001)화표체경다적방어소기인(P<0.05)이보호장점막。유차가지,단내전,자저건강상황하장도병장완정,sIgA화방어소표체적수평상대교저,단내파배료장도완정성,사득장도융모위축,은와증생,장도상피병장수도손상,대량적림파세포추화지장도상피,동시단내시미생물입침자격료장상피면역구단백화방어소적분비。
This study was conducted to investigate the changes of intestinal morphology and immune-related protein gene expressions in piglets before and after weaning. A total of 24 healthy piglets from 6 litters with 1 piglet per litter were slaughtered at 7, 14, 21 and 35 days of age (weaned at 21 days of age), then duodenum and jejunum were collected. The intestinal morphology, intra-epithelial lymphocytes number and goblet cells number, jejunal secretory immunoglobulin A ( sIgA) concentration and defensin gene expressions were tested using haematoxylin and eosin staining, ELISA or real time quantitative PCR, respectively. The results showed as follows:during 7 d to 21 d after born, we found that the villous height of duodenum and jejunum was shor-ter in 14 and 21 d compared with 7 d ( P<0 . 05 ) , meanwhile the crypt depth in duodenum tended to be gradu-ally decreased following age, but the intestinal epithelial goblet cells number and intra-epithelial lymphocytes number were not significantly changed (P>0. 05). After weaning (35 d after born), in jejunum, the villous height was significantly decreased compared with 7 d ( P <0 . 05 ) and the crypt depth was significantly in-creased compared with that before weaning (during 7 d to 21 d after born) (P<0. 05). Compared with that before weaning, the intra-epithelial lymphocytes number of duodenum and jejunum was significantly increased after weaning ( P<0 . 05 ) . The sIgA concentration ( P=0 . 001 ) and defensin gene expressions in jejunum of weaned piglets were significantly higher than those of before-weaning piglets ( P <0 . 05 ) . From the results, we can find that piglets have a healthy intestinal barrier and low-expression levels of sIgA and defensins before weaning. After weaning, the weaning stress disturbances the intestinal mucosal integrity because of the atrophy of the villi and the proliferation of crypt, and intestinal barrier is destroyed, meanwhile, the number of intra-epithelial lymphocytes is increased. The infection of bacteria stimulates the expressions of immunoglobulin and defensins after weaning.