Objective To investigate the pathological changes of cardiac collagen in the elderly patients with hypertensive left ventricular hypertrophy(LVH)and the difference of collagen among the groups of essential hypertension(EH),diabetes (T2DM) under the condition of the same stage,providing pathological foundation of clinical treatment for curing diseases and the early heart protection.Methods A retrospective study was performed in 140 cases over 65 years old of EH and normal cases as control out of 3520 consecutive autopsied cases from 1954 to 2001 in Chinese People's Liberation Army (PLA) General Hospital.The pathological changes of collagen were studied with hematoxylin and eosion(HE) staining,Sirius Red F3B (SR)and immunohistochemistry staining.Myocardial interstital collagen deposition was observed with light microscope and polarization technique.Quantitative measurements on the myocardial collagen volume fraction (CVF),CVFS of type Ⅰ and type Ⅲ,and the rate of collagen type Ⅰ to type Ⅲ (Ⅰ/Ⅲ) were determined with videodensitometry.Results The CVF(6.32％ ± 0.92％) and CVF Ⅰ (5.93％ ± 0.94％)were increased significantly in EH LVH Ⅰ group (P ＜0.01) ; but,CVF Ⅲ (2.23％ ±0.38％) and Ⅰ/Ⅲ (2.69 ±0.42) did not change significantly in EH Ⅰ group compared with the control group; The changes in the aforementioned four items were increased significantly in EH LVH Ⅱ and EH LVH Ⅲ groups (P ＜0.01)compared with the control group.The CVF and CVF-Ⅰ were decreased significantly(P ＜ 0.01) ; but CVF-Ⅲ and Ⅰ/Ⅲ did not change significantly in DM LVH-I group compared with the EH LVH-I group; the CVF(4.23％ ± 0.69％) and CVF-Ⅰ (3.92％ ±0.40％) were decreased significantly(P ＜0.01); but CVF-Ⅲ(1.79％ ±0.21％) and Ⅰ/Ⅲ (2.20 ±0.20) did not change significantly in DM LVH-Ⅰ group compared with the EH LVH-Ⅰ group.Conclusions (1)The myocardial stiffness and the reduction of cardiac diastolic function deteriorated most with the development of LVH.(2)Under the condition of the same stage,the myocardial stiffness and the reduction of cardiac diastolic function deteriorated seriously in EH groups,diabetes patients,myocardial stiffness and the reduction of cardiac diastolic function deteriorated slightly.