Experimental research on “the external-internal relationship between heart and small intestine in TCM”^*

ZHOU Mei-Qi¹ , ZHOU Yi-Ping² , XU Guan-Sun² and GAO Xin-Zhu¹


Abstract
AIM To verify the external-internal relationship between the heart and the small intestine in TCM.
METHODS Thirty rabbits were randomly allocated into 3 group: partly ligated small intestine group; partly ligated rectum group and control group. EKG, pathomorphology and histopathology were studied.
RESULTS As compared with control group and partly ligated rectum group, the partly ligated small intestine group manifested modest or moderate hyperemia and slight dilatation of cardiac chambers in some rabbits by gross inspection. Moreover, blood stasis in the interstitium, degeneration of myocardial fibers and focal necrosis were seen under light microscopy with statistical significances (P<0.005 and P<0.001). EKG showed T wave changes and arrhythmia.
CONCLUSON The theory of external-internal relationship between the heart and the small intestine is not an assumption, it has a valid scientific basis.INTRODUCTION
The external-internal relationship is one of the important parts of visceral manifestation therapy and the meridian doctrine in traditional Chinese medicine^[1] . It includes the external-internal relationship between the Zang (solid) and Fu (hollow) organs and the interconnection between Yin and Yang channels (Yin and Yang, a general term for two opposite aspects of matters in nature). The purpose of this paper is to explore the external-internal relationship between the heart and the small intestine by observing the changes of electrocardiagram, pathomorphology and histopathology of the hearts of the rabbits with partly ligated small intestine.

MATERIALS AND METHODS
Animals
Healthy rabbits, weighing 2?kg-2.5?kg, regardless of male and female, were supplied by the Centre of Experimental Animals in our college.

Methods
Thirty rabbits were randomly allocated into three groups. Before the experiment, all rabbits were fasted for 12 hours, and were anesthetized with ethyl carbamate (1?g/?kg) and operation performed. The rabbits in control group received sham-operation, the ileum and the rectum were taken out and then put back; in partly ligated small intestine group the ligature was set at the junction of ileum and cecum; and in partly ligated rectum group the ligature was set at the rectum 2?cm-3?cm from the anus.
Each experiment lasted three days and EKG was recorded twice a day after operation. All rabbits were killed three days afterwards. The heart was grossly inspected, then fixed in 20% formaldehyde solution, dehydrated, paraffin embedded, sectioned, stained with hematoxylin and examined under microscopy.

Statistical analysis
Statistical analysis was made by using H test and difference between two groups was by t test. P<0.05 was considered statistically significant.
RESULTS
Main features of EKG in rabbits
After partial ligation of small intestine, the rabbits＇ heart rate increased from 201min±14min to 263min±16min, T waves reduced in height or flattened or even inverted. Some showed prolongation of Q-T interval, atrial and ventricular premature beats, one of them showed ventricular fibrillation at 72 hours. In partly ligated rectum group and normal control group, there were no obvious changes except some T wave changes.

Changes in cardiac pathomorphology
Partly ligated small intestine could lead to cardiac pathomorphologic changes (H=18.13,P<0.005), which was markedly significant as compared with the partly ligated rectum group and normal control group, P<0.001. No changes were seen in the latter two groups (P>0.5) (Tables 1-3). In addition, in the former group, there were 7 rabbits showing slight dilatation of cardiac chambers.


Table 1 Changes in cardiac pathomorphology

Table 2 Changes of cardiac pathomorphology

Table 3 Comparison of the two groups on changes of cardiac pathomorphology