| Background: Erectile Dysfunction(ED) is one of the most common disorders in the practice of urology, of which aging is a putative risk.Sildernafil, a type V phosphodiesterase inhibitor that inhibits the degradation of cGMP, has been used prevalently to treat ED world-widely. However, most physicians and patients feel so satisfied with temporary amelioration of erectile dysfunction that they trend to neglect further investigation on the etiological factors and prevention as well as treatment of ED. Some scholars hold that most patients previously classified as psychogenic ED are of organic origin. We can expect that a lot of patients with ED will fail to respond to sildenafil in the future. Alterations such as severe tissue fibrosis of penis in these patients will beirreversible. Up to date, the underlying mechanism of organic changes in ED is still obscure. The number of smooth muscle cells in ED penis decreases, which is caused by smooth muscle cell conversion to fibroblast just as been suggested by some scholars. But injection of antisense TGF β ,a inhibitor for fibrosis of smooth muscle, got poor results. We postulate that more important cause of smooth muscle decrease lies in accelerated cell senescence of smooth muscle, while slower cell senescence of fibroblast leads to accumulation of collagen.Objective: To explore the effects of aging on NO-cGMP way, telomerase and component of penile tissue and the effects of Tankyrasel , hTERT transfection on smooth muscle musclesMethods: We had made some study with different month age (2,8,16,24month ) rats and cultured smooth muscle cells , as follows::(1): The NO, NOS activity, cGMP contents , the distribution of NOS , the structure of penile tissue and telomerase activity were detected, the telomerase activity of SMC anfd penile tissue between rat and human were compared;(2)Primary cultures of smooth muscle cells of rat CorpusCavernosum were carried out by tissue piece method, the eukaryotic expression vectors for sense Tankyrasel was constructed and then transfected the smooth muscle cells , the biological alterations of transfected cells were determined;(3) Primary cultures of smooth muscle cells of human Corpus Cavernosum were carried out by tissue piece method, the eukaryotic expression vectors for sense hTERT was constructed and then transfected the smooth muscle cells , the biological alterations of transfected cells were determined.Results: 1. The NO content and NOS activity of penile tissue firstly rose ( month 8, the highest) then dropped ( month 24 , the lowest) .The positive staining of NOS existed mainly in smooth muscle cell and decreased significantly with aging ,month 2 was the most abundant and month 24 was the lest, the cGMP contents decreased markedly. The Masson staining showed that: smooth fibers decreased while collagen fibers increased. The five tissues and cultured SMC of rat had telomerase activity, and the level of telomerase activity in testicle was the highest, the month 2 was the highes in penile tissue. No telomerase activity in human penile tissue and a lilltle in primary cultures of smooth muscle cells of human Corpus Cavernosum.2. Primary cultures of smooth muscle cells of rat Corpus Cavernosum were carried out successfully, the eukaryotic expression vectors for sense Tankyrasel was constructed and then transfected the smooth muscle cells also successfully, the telomerase activity of transfected cells was similar, the OD value and cell devision index of TNKS-transfected cell were significantly higher than that of the non-transfected cells, apoptosis was lower in TNKS-transfected cell.3. Primary cultures of smooth muscle cells of human Corpus Cavernosum were carried out successfully, the fluorescent eukaryotic expression vectors for sense hTERT was constructed and then transfected the smooth muscle cells also successfully, the telomerase activity, the OD value and cell devision index of hTERT -transfected cell were significantly higher than that of the non-transfected cells, apoptosis was lower in hTERT -transfected cell.Conclusions: 1. The effects of aging on NO-cGMP way, telomerase and component of penile tissue are significantly, which indicated that aging is correlated to ED tightly.2. Telomerase activity existed in rat penile tissue and no in human penile tissue, which indicated that rat can be used the animal model about cell senescence and ED.3. The success of primary cultures of smooth muscle cells of rat and human Corpus Cavernosum can help study the mechanism of ED.4. The eukaryotic expression vectors for sense Tankyrasel was firstly transfected the smooth muscle cells of rat, which can enhance cell proliferation and decrease cell apoptosis.5. The fluorescent eukaryotic expression vectors for sense hTERT was firstly transfected the smooth muscle cells of human, which can increase telomerase activity and decrease cell apoptosis.6. The results of this study indicated that the combination transfection of hTERT and Tankyrasel probably can prolong the life of smooth muscle cell and prevent organic ED. |
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