The Expression And Significance Of MAPK In Benign Prostatic Hyperplasia Tissues

ObjectiveBenign prostatic hyperplasia (BPH) is a common disease involved in aged men, which dose great harm to their health. Up till now, we know little about the pathogenesis of this disease that occurs in aged men with functional testes and have no effective drugs that can prevent the development of BPH completely. Therefore, its necessary to do further investigation in the molecular mechanisms of BPH in order to provide theoretic foundation on which more effective therapeutic drugs can be developed.Mitogen - activated protein kinases (MAPK) are a series of signal transferors mainly consisting of extracellular signal - regulated kinase ( ERK1/2 ) , stress - activated protein kinase ( SAPK.) /c - Jun N - terminal kinase ( JNK) and P38. MAPK play very important role in integrating physiological and pathological courses such as cellular growth, development, differentiation and apopto-sis. ERK are mainly engaged in cell proliferation and differentiation, while SAPK/JNK and P38 are implicated in stress - induced response and apoptosis. Abnormal MAPK signal - tranduction pathways can result in a proliferative - ap-optotic imbalance, which can cause cell excessive hyperplasia. This may play role in the pathogenesis of BPH.We examined the expression of ERK (1/2) , SAPK/JNK and P38 in BPH and normal prostatic tissues by immunohistochemical techniques (S - P) to investigate whether there were anomalies of MAPK activities and the effects in the pathogenesis of BPH.Materials and Methods1. Experimental objectsThere were 28 cases of BPH specimens obtained by suprapubic prostatectomy. The patients aged from 57 to 78. They had never received any hormonal treatment before operation. Normal prostates were obtained at autopsy ( within 8 hours after death) from 8 men aged 24 to 35. All specimens were approved by two pathologists.2. Mathods(1) Embedding and routine continuous section for tissue samples with 6 m thickness;(2) HE staining;(3) Immunohistochemical techniques ( S - P ) were used to detect the expression of ERK JNK and p38 ;(4) Results determinationActive MAPK mainly located in the nucleus, so in immunohisto - chemistry (S -P) , cells with brown nucleuses were regarded as positive. The proportion of positive cells was counted respectively in 200 epithelial and basal cells in five high - power visual fields selected randomly.3. Statistical analysisSPSS statistical software was used for statistical analysis. The comparison between mean values was performed by t - test.Results1. In immunohistochemistry of ERK, the percentages of positive cells in epithelial and stromal were higher in BPH tissues (72. 95 1. 84% and 78. 88 1.39% respectively) than that in normal prostatic tissues (0. 19 0. 13% and 46.38 3.14%)(P<0.01).2. For JNK, the proportions of positive cells of epithelial were 26. 84 2. 55% and 23. 63 卤2. 66% in BPH and normal tissues respectively, While thevalues were 18.52 1. 49% and 20. 63 2. 47% in stromal cells. There were no significant differences in either group (P>0.05).3. As to P38, the proportions of positive cells of epithelial were 28.63 1. 62% and 31. 94 3. 02% in BPH and normal tissues respectively, While the values were 24.75 1. 68% and 27. 00 3. 12% in stromal cells. There were no significant differences in either group (P >0.05).Conclusion1. The expression of ERK1/2 increased in BPH tissue and the expressions of SAPK/JNK and P38 have no significant changes.2. The increasing of the proliferation mediated by the over expression of ERK and the unchanged apoptosis mediated by SAPK/JNK and P38 may result in a proliferative - apoptotic imbalance, which may lead to the development of BPH.