牛初乳(BC)和鸡蛋含有具有生长因子活性的蛋白质。表皮生长因子(EGF)在BC中提供了许多促修复活性。口服施用的肽生长因子的临床使用受到来自胰腺蛋白酶的消化的阻碍。
我们使用体外和体内模型检查了添加蛋白酶抑制剂[大豆胰蛋白酶抑制剂(SBTI)或卵类粘蛋白]是否单独保护BC±卵或EGF的生物活性以抵抗胰腺消化。
BC,鸡蛋,或单独或与胰蛋白酶抑制剂组合的EGF使用人胃腺癌(AGS)细胞测试增殖(Alamar蓝)活性,在用HCl/胃蛋白酶和胰蛋白酶/胰凝乳蛋白酶孵育之前和之后。使用2因素ANOVA分析数据。八组(n=10)成年雌性Sprague-Dawley大鼠(平均:188.3±0.8g)接受20mg/kg/d的BC蛋,100μg/d的EGF,5毫克/天的卵粘胶,或10.8毫克/天SBTI,单独或组合(在1mL3%NaHCO3中)通过管饲法9d和葡聚糖硫酸钠(DSS;饮用水中5%)进行最后7d。组织学,微观损伤评分,使用单因素方差分析评估和分析髓过氧化物酶(MPO)。
BC的增殖活性,鸡蛋,或EGF通过HCl/胃蛋白酶暴露减少40-57%,而胰凝乳蛋白酶/胰蛋白酶进一步减少14-24%。SBTI或卵类粘蛋白的共同添加将胰凝乳蛋白酶/胰蛋白酶引起的增殖生物活性降低缩短了54-100%(P<0.01)。体内研究表明,单独口服EGF或单独给予蛋白酶抑制剂对减少DSS损伤无效,而带有EGF的SBTI或带有BC+鸡蛋的卵类粘蛋白改善了对体重增加的保护作用,疾病活动评分,结肠MPO,和组织学损伤3-4倍(P<0.01)。
使用AGS的研究,细胞,Sprague-Dawley大鼠显示蛋白酶抑制剂卵类粘蛋白和SBTI保护BC,鸡蛋,和EGF防止由于胰腺酶而导致的生物活性丧失,当给予NaHCO3时,增强了对DSS损伤的结肠保护。
Bovine colostrum (BC) and chicken egg contain proteins possessing growth factor activity. Epidermal growth factor (EGF) provides much of the pro-reparative activity within BC. Clinical use of orally administered peptide growth factors is hampered by digestion from pancreatic proteases.
We examined whether adding a protease inhibitor [soybean trypsin inhibitor (SBTI) or ovomucoid] protected bioactivity of BC ± egg or EGF alone against pancreatic digestion using in vitro and in vivo models.
BC, egg, or EGF alone or in combination with trypsin inhibitors were tested for proliferative (Alamar blue) activity using human gastric adenocarcinoma (AGS) cells, prior to and after incubation with HCl/pepsin and trypsin/chymotrypsin. Data were analyzed using 2-factor ANOVA. Eight groups (n = 10) of adult female Sprague-Dawley rats (mean: 188.3 ± 0.8 g) received 20 mg/kg/d of BC + egg, 100 μg/d of EGF, 5 mg/d ovomucoid, or 10.8 mg/d SBTI, alone or in combination (in 1 mL 3% NaHCO3) by gavage for 9 d and dextran sodium sulfate (DSS; 5% in drinking water) for the final 7 d. Histology, microscopic damage score, and myeloperoxidase (MPO) were assessed and analyzed using 1-factor ANOVA.
Proliferative activities of BC, egg, or EGF were reduced 40-57% by HCl/pepsin exposure and further reduced 14-24% by chymotrypsin/trypsin. Co-addition of SBTI or ovomucoid truncated the decrease in proliferative bioactivity caused by chymotrypsin/trypsin by 54-100% (P < 0.01). In vivo study showed oral EGF alone or protease inhibitors given alone were ineffective in reducing DSS damage, whereas SBTI with EGF or ovomucoid with BC + egg improved protective effects on weight gain, disease activity score, colonic MPO, and histology damage by 3-4-fold (P < 0.01).
Studies using AGS, cells, and Sprague-Dawley rats showed the protease inhibitors ovomucoid and SBTI protected BC, egg, and EGF against loss of bioactivity due to pancreatic enzymes and, when given with NaHCO3, enhanced colonic protection against DSS damage.