Department of Physiology, CUCS, University of Guadalajara, Guadalajara, Jalisco 44340, México.
World J Gastroenterol. 2011 Sep 7;17(33):3830-5. doi: 10.3748/wjg.v17.i33.3830.
To demonstrate that CD14⁺ cells are an important source of the growth factor YKL-40 in acute and chronic liver damage.
Rats were inoculated with one dose of CCl(4) to induce acute damage. Liver biopsies were obtained at 0, 6, 12, 24, 48 and 72 h. For chronic damage, CCl(4) was administered three days per week for 6 or 8 wk. Tissue samples were collected, and cellular populations were isolated by liver digestion and purified by cell sorting. YKL-40 mRNA and protein expression were evaluated by real-time polymerase chain reaction and western blot.
Acute liver damage induced a rapid increase of YKL-40 mRNA beginning at 12 h. Expression peaked at 24 h, with a 26-fold increase over basal levels. By 72 h however, YKL-40 expression levels had nearly returned to control levels. On the other hand, chronic damage induced a sustained increase in YKL-40 expression, with 7- and 9-fold higher levels at 6 and 8 wk, respectively. The pattern of YKL-40 expression in different subpopulations showed that CD14⁺ cells, which include Kupffer cells, are a source of YKL-40 after acute damage at 72 h [0.09 relative expression units (REU)] as well as after chronic injury at 6 wk (0.11 REU). Hepatocytes, in turn, accounted for 0.06 and 0.01 REU after 72 h (acute) or 6 wk (chronic), respectively. The rest of the CD14⁻ cells (including T lymphocytes, B lymphocytes, natural killer and natural killer T cells) yielded 0.07 and 0.15 REU at 72 h and 6 wk, respectively. YKL-40 protein expression in liver was detected at 72 h as well as 6 and 8 wk, with the highest expression relative to controls (11-fold; P ≤ 0.05) seen at 6 wk. Macrophages were stimulated by lipopolysaccharide. We demonstrate that under these conditions, these cells showed maximum expression of YKL-40 at 12 h, with P < 0.05 compared with controls.
Hepatic CD14⁺ cells are an YKL-40 mRNA and protein source in acute and chronic liver injury, with expression patterns similar to growth factors implicated in inflammation-fibrogenesis.
证明 CD14⁺细胞是急性和慢性肝损伤中生长因子 YKL-40 的重要来源。
用 CCl(4) 单次注射诱导急性损伤，分别于 0、6、12、24、48 和 72 h 取肝活检。慢性损伤时，CCl(4)每周 3 天给药，共 6 或 8 周。采集组织样本，通过肝消化分离细胞群，并用细胞分选进行纯化。用实时聚合酶链反应和蛋白质印迹法评估 YKL-40 mRNA 和蛋白表达。
急性肝损伤 12 h 内迅速诱导 YKL-40 mRNA 增加，24 h 达高峰，较基础水平增加 26 倍。然而，72 h 时 YKL-40 表达水平几乎恢复到对照水平。另一方面，慢性损伤诱导 YKL-40 持续表达增加，6 周和 8 周时分别增加 7 倍和 9 倍。不同亚群中 YKL-40 表达模式表明，CD14⁺细胞（包括库普弗细胞）是急性损伤后 72 h （0.09 相对表达单位 [REU]）和慢性损伤后 6 周（0.11 REU）YKL-40 的来源。相反，肝细胞在 72 h （急性）或 6 周（慢性）时分别占 0.06 和 0.01 REU。其余 CD14⁻细胞（包括 T 淋巴细胞、B 淋巴细胞、自然杀伤细胞和自然杀伤 T 细胞）在 72 h 和 6 周时分别产生 0.07 和 0.15 REU。肝内也检测到 YKL-40 蛋白表达，72 h 以及 6 周和 8 周时均高于对照组（11 倍；P ≤ 0.05），6 周时最高。用脂多糖刺激巨噬细胞，我们证明在这些条件下，这些细胞在 12 h 时表现出 YKL-40 的最大表达，与对照组相比 P < 0.05。
肝 CD14⁺细胞是急性和慢性肝损伤中 YKL-40 mRNA 和蛋白的来源，其表达模式与参与炎症纤维化的生长因子相似。
