| Objective: Benign prostatic hyperplasia (BPH) is one of the most common diseases in aged male. Its incidence has been going up with advancing age. Two groups of clinical symptoms are caused by BPH— bladder irritative symptoms, obstructive symptoms . The bladder irritative symptoms include urinary frequency, urgency, nycturia and urgent incontinence. Detrusor instability (DI) is the major reason which causes the bladder irritative symptoms. The obstructive symptoms include urinary hesitancy, straining, decreased force of urination, dribbling, urinary retention and urinary retention with overflow incontinence. And the damage of contractile function of detrusor muscle is the major reason of these symptoms. Now there are many investigations to approve that the growth factors playing important roles in the proceeding of BPH. But what we know is very poor about the relationship between the growth factors and the changes of detrusor muscle after BPH. Epidermal growth factor (EGF) can promote many kinds of cell's proliferation significantly. Basic fibroblast growth factor (bFGF) is important to the growth and development of human bladder and can promote cell proliferation. Increased levels of bFGF have been reported in the bladder tissues of obstructed animal bladders where there is accompanying denervation. Our present study aims at investigating the changes of EGF and bFGF in human bladder smooth muscle in BOO due to BPH and their implication by detect the expression of EGF and bFGF in the levels of protein and mRNA.Materials and Methods: Our study included 15 cases of bladder cancer and 54 patients with BPH. All patients were divided into three groups according to his conclusionof urodynamic investigation, a control group, an obstructive detrusor stability group and an obstructive detrusor instability group. The control group contained 15 aged male patients of bladder cancer without BOO and DI by urodynamic investigation. The obstructive detrusor stability group contained 33 patients of BPH. There were 21 cases of BPH in the obstructive instability group. There were no significant differences among the mean ages of the three groups. According to the recommendations of the International Consensus Committee on BPH (ICCBPH), patients with BPH performed basic initial evaluations (history, physical examination, digital rectal examination, urinalysis, serum PSA and renal function assessment) and recommended diagnostic tests (uroflowmetry, residual volume, ultrasonography and urodynamic study). All patients had undergone an opening surgery of bladder and during the operation 2 small pieces of detrusor muscle were cut from the edge of the incision on the anterior bladder wall. One sample each was frozen in liquid nitrogen and used for a RT-PCR and the other for an immunohistochemical study.1 .RT-PCR: The total cellular RNA was extracted from bladder detrusor tissues. The electrophoresis of formaldehyde gel was done for each sample to ensure the integrity of RNA. A reverse transcription polymerase chain reaction (RT-PCR) was performed to examine EGFmRNA and bFGFmRNA. The aliquots of the amplified DNA by polymerase chain reaction were electrophoresed on 1.5% agarose gel and visualized by ethidium-bromide fluorescence. Observed and took photo under xeno-viovet transmission apparatus. A reverse transcription polymerase chain reaction (RT-PCR) for (3-actin was also done. The signals were quantified by using Scientific Imaging Systems.2.1mmunohistochemical study: The immunohistochemical analysis for EGF and bFGF were performed by using streptavidin biotin horseradish peroxidase staining in the control group, the obstructive detrusor stability group and the obstructive detrusor instability group. Replacing the primary antibody with PBS made the negative contrast.The statistical analyses were performed using the software of SPSS 12.0 statistical package. P value less than 0.05 was regarded as significant and P value less than 0.01 was regarded as very significant.Results: 1. The RT-PCR study indicated that EGF mRNA and bFGFmRNA were expressed in bladder detrusor of three groups of patients. The bFGF -mRNA expressionlevel of bladder smooth muscle cells in the control group was significant different to those in the obstructive detrusor stability group and the obstructive instability group, but there were no significant difference between the bFGFmRNA expression level in the obstructive detrusor stability group and that in the obstructive instability group.The expression levels of EGFmRNA were 0.5208±0.1692 in the control group, 0.5711±0.2842 in the obstructive detrusor stability group and 0.6323±0.2837 in the obstructive instability group. There were no significant differences among the three groups(P>0.05) .2. The immunohistochemical study indicated that bFGF and EGF were expressed in cytoplasm of bladder smooth muscle cells. The expression levels of bFGF in the obstructive detrusor stability group and in the obstructive instability group were significantly increased compared with that in the control group, the difference reached statistical significance (P< 0.01). And there was no significant difference between the obstructive detrusor stability group and the obstructive instability group (P>0.05). And there was no significant difference among the EGF expression levels in three groups. (P > 0.05)Conclusion:1. The expression levels of bFGF and bFGFmRNA in bladder detrusor were elevated in BOO due to BPH. The increased bFGF level of bladder smooth muscle cells was correlated with the alterations of bladder detrusor due to BOO, but there may be no correlation between the increased expression of bFGF and DI.2. There were no significant changes in the expression levels of EGF and EGFmRNA in bladder detrusor in BOO due to BPH.3. This study investigated potential mechanisms of the changes of bladder detrusor associated with BOO due to BPH. It will provide a new idea for clinical treatment and researching new drugs. |
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