Objective:To investigate the laxative effect of Puerarin on constipation in mice, and to explore the involved mechanism. Methods: Constipation model was established by diphenoxylate. After the constipation model were treated with Puerarin, several factors were observed after Puerarin treated constipation model, including the first defecation time. And the effects of Puerarin on water contents of large intestine and activity of isolated large intestinal smooth muscle were studied by weighing the intestine and Powerlab signal processing system respectively. Results: ① Compared with the model group, Puerarin could shorten the first defecation time and enhance two other factors such as the amount of feces within 12 hours, the weight of feces ( P0. 05). ② Compared with model group, low and medium dose of Puerarin could significantly increase the water content in large intestine ( P0. 05). And the above factor in high dose Puerarin group is higher than the control and model group ( P0.05). ③ Puerarin could further enhance the inhibitory effect of diphenoxylate on the scope , frequency and curve of activities of intestine smooth muscle contraction. Conclusion:Puerarin can defecate feces excretion, whose possible mechanism is that the stimulatory effect by increasing water in intestine is stronger than the direct inhibitory effect on the intestinal activities.

According to the advantages and disadvantages of the clinical medical educa-tion of the ordinary specialized subject-to-undergraduate,the traditional teaching method has been improved in two aspects:choosing case and teaching process.It can be conformed that teaching method of case-based learning is very suitable for physiological teaching.It can improve the effective interaction of teachers and students,and enchance the students' abilities of self-study and theory with practice.

Objective To investigate whether γH2AX is a sensitive,rapid and simple technique in detecting formaldehyde induced DNA damage.Methods After V79 lung cells were treated with formaldehyde,γH2AX foci formation was detected by immune-fluorescent microscopy.Single cell gel electrophoresis was employed to detect DNA damage.Results Increase of the formation of γH2AX foci could be induced by treating V79 lung cells in 20 μmol/L formaldehyde for 10 min,however,the increase of comet tail length would increase only 2 h later.When the cells were treated with 1 μmol/L formaldehyde for 8 h,the mean value of foci per cell and the percentage of γH2AX foci cells increased significantly compared with the control(P0.05),however,this dosage could not increase comet tail length at any time duration.Conclusions γH2AX could detect formaldehyde induced DNA damage at early stage,moreover,DNA damage induced by low concentration formaldehyde could also be detected.It is more sensitive than single cell gel electrophoresis.

AIM To determine the exact roles of prolactin (PRL) in the pathogenesis of rheumatoid arthritis (RA) and supply experimental basis for clinical treatment of RA, and to investigate the expression of matrix metalloproteinase-9 (MMP-9) in the synovium of adjuvant arthritis rats. METHODS Forty rats were divided into four groups (n = 10): (1) Normal control group (group A); (2) Adjuvant arthritis control group (group B); (3) Hyperprolactinemic adjuvant arthritis group (group C); (4) Hypoprolactinemic adjuvant arthritis group (group D). The content of PRL in the serum was detected by radio-immunoassay method. The activity of MMP-9 was analyzed by gelatin zymography. The alteration of MMP-9 immunoreactivity were investigated by means of immunohistochemistry in the synovium of all groups. The expressions of MMP-9 were investigated by Western blot in the synovium of all groups. RESULTS Compared with group A, the activity and expression of MMP-9 of group B in the synovium were highly increased. The activity and expression of MMP-9 in the synovium were the most distinctive in group C. Compared with group B, the activity and expression of MMP-9 in the synovium were decreased in group D, but still higher than group A. CONCLUSION The present results indicated that PRL might involved in the pathogenesis of RA by regulating the secretion of MMP-9 in the synovium.