目的　研究内皮型一氧化氮合成酶 (Endothelialnitricoxidesynthase ,eNOS)及其mRNA在慢性乙型肝炎 (ChronichepatitisB ,CHB)肝组织中的表达及与肝组织病变的关系和临床意义。方法　采用免疫组化及核酸原位杂交等技术对 48例CHB肝组织中eNOS的表达进行了观察和分析 ,同时研究了eNOS对CHB肝组织中转化生长因子 β受体Ⅰ (Transforminggrowthfactor βreceptorⅠ ,TGF βRⅠ )的表达的影响。结果　eNOS主要表达于肝细胞、窦内皮细胞及血管内皮细胞 ,以肝细胞为主。连续切片观察 ,eNOSmRNA的表达与其酶蛋白的表达在阳性细胞数量及分布上基本一致。随CHB肝组织炎症程度和纤维化程度的加重 ,eNOS表达增强 (r =0 6 85 5 ,P <0 0 5 ;r =0 482 8,P <0 0 5 )。随eNOS表达上调 ,患者PA及血清ALB下降 (F =3 410 1,P <0 0 5 ;F =9 1714,P <0 0 1)。CHB肝组织内eNOS的表达与TGF βRⅠ的表达呈明显正相关 (r =0 7781,P <0 0 5 )。 结论　eNOS可能通过影响TGF βRⅠ在肝组织中的表达 ,参与CHB肝组织病理损伤过程 Objective To study the relationship between the expression of endothelial nitric oxide synthase (eNOS) and its mRNA in the liver of Chronic Hepatitis B (CHB) and its relationship with the pathological changes of liver and its clinical significance. Methods The expression of eNOS in 48 CHB liver tissues was observed and analyzed by immunohistochemistry and in situ hybridization. Meanwhile, the effect of eNOS on the expression of transforming growth factor β receptor Ⅰ (TGFβR Ⅰ) ) Expression. Results eNOS was mainly expressed in hepatocytes, sinus endothelial cells and vascular endothelial cells, mainly hepatocytes. Serial sections were observed, eNOSmRNA expression and enzyme protein expression in the number and distribution of positive cells are basically the same. With the severity of CHB liver inflammation and fibrosis, eNOS expression was enhanced (r = 0 6 85 5, P <0 05; r = 0 482 8, P 0 05). As eNOS expression increased, PA and serum ALB decreased (P = 4101, P <0.05; F = 91714, P <0.01). The expression of eNOS in CHB liver tissue was positively correlated with the expression of TGFβRⅠ (r = 0 7781, P <0 05). Conclusion eNOS may be involved in the pathogenesis of CHB by affecting the expression of TGFβRⅠ in liver tissue