Fraction Of Smooth Muscle Research Articles

Human umbilical cord mesenchymal stem cells reconstruct the vaginal wall of ovariectomized Sprague-Dawley rats: implications for pelvic floor reconstruction.

Vaginal structural defects are involved in pelvic organ prolapse (POP). We tested whether mesenchymal stem cell (MSC) therapy can repair the weakened vaginal wall of POP patients as a novel POP treatment. Ninety-six ovariectomized rats were divided into 4 groups (n = 24/group): saline (sal), collagen (col), sal + MSC, and col + MSC groups. Two weeks after ovariectomy, rats received subepithelial injection of 0.3ml saline, 0.3ml collagen I gel, and 0.3ml saline: 3 × 106 human umbilical cord mesenchymal stem cells (HUMSCs), or 0.3ml collagen I gel: 3 × 106 HUMSCs into the anterior vaginal wall. Eight additional rats underwent in vivo bioluminescence imaging (BLI) to evaluate in vivo cell viability. The BLI signal disappeared within 1week after MSC injection, and no in vivo MSC differentiation was found. Collagen I content was significantly lower at 4 and 12weeks in the two MSC groups than in the sal and col groups, while collagen III was significantly higher (P < 0.001). The fraction of smooth muscle in the nonvascular muscularis increased significantly in the two MSC groups at 12weeks (P < 0.001). ACTA2 mRNA in the col + MSC group was significantly higher than that in the sal group at 2 and 4weeks (P = 0.042 and P = 0.040). mRNA levels of angiogenic factors (bFGF or VEGF) in the two MSC groups were significantly higher than those in the sal and col groups at different time points. HUMSCs normalized the fibromuscular structures of the vaginal wall of ovariectomized rats potentially through a paracrine effect.

Mesenchymal stem cell transplantation for vaginal repair in an ovariectomized rhesus macaque model

BackgroundCurrent surgical therapies for pelvic organ prolapse (POP) do not repair weak vaginal tissue and just provide support; these therapies may trigger severe complications. Stem cell-based regenerative therapy, due to its ability to reconstruct damaged tissue, may be a promising therapeutic strategy for POP. The objective of this study is to evaluate whether mesenchymal stem cell (MSC) therapy can repair weak vaginal tissue in an ovariectomized rhesus macaque model.MethodsA bilateral ovariectomy model was established in rhesus macaques to induce menopause-related vaginal injury. Ten bilaterally ovariectomized rhesus macaques were divided into two groups (n=5/group): the saline group and the MSC group. Three months after ovariectomy, saline or MSCs were injected in situ into the injured vaginal wall. The vaginal tissue was harvested 12 weeks after injection for histological and biochemical analyses to evaluate changes of extracellular matrix, microvascular density, and smooth muscle in the vaginal tissue. Biomechanical properties of the vaginal tissue were assessed by uniaxial tensile testing. Data analysis was performed with unpaired Student’s t test or Mann-Whitney.ResultsTwelve weeks after MSC transplantation, histological and biochemical analyses revealed that the content of collagen I, elastin, and microvascular density in the lamina propria of the vagina increased significantly in the MSC group compared with the saline group. And the fraction of smooth muscle in the muscularis of vagina increased significantly in the MSC group. In addition, MSC transplantation improved the biomechanical properties of the vagina by enhancing the elastic modulus.ConclusionVaginal MSC transplantation could repair the weak vaginal tissue by promoting extracellular matrix ingrowth, neovascularization, and smooth muscle formation and improve the biomechanical properties of the vagina, providing a new prospective treatment for POP.

Tissue Composition and Biomechanical Property Changes in the Vaginal Wall of Ovariectomized Young Rats.

Ideal animal models are needed to reflect the changes in the biochemical and biomechanical properties of the vagina that occur in pelvic organ prolapse (POP). In this study, we aimed to demonstrate the short and long-term effect of menopause on the biochemical and biomechanical properties of rat anterior vaginas. Here, Sprague-Dawley rats were bilaterally ovariectomized to induce menopause. Rats without ovariectomy served as the normal control group (n=12). The histology changes and the expression of collagen I, III, and a-SMA were assessed to indicate the biochemical changes in the vagina 2 weeks, 4 weeks, and 16 weeks after ovariectomy (n=6 for 2 and 4 weeks, n=12 for 16 weeks). Uniaxial biomechanical testing was conducted in the control group and ovariectomized rats 16 weeks after ovariectomy. Compared with the control group, the ovariectomy group showed a significant increase in the expression of collagen I 2 weeks after ovariectomy, while collagen III showed a declining trend. Two weeks after ovariectomy, the smooth muscle bundles began to become disorganized, and the fraction of smooth muscle in the nonvascular muscularis of the proximal vagina was significantly decreased (P<0.001). However, there was no difference in the expression of a-SMA in the distal vagina. Compared with the control group, the ovariectomy group had stiffer vaginas with a declining trend in the ultimate load 16 weeks after ovariectomy. In conclusion, surgically induced menopause had a significant short- and long-term impact on tissue composition and biomechanical properties of the rat vagina, which may lead to increased susceptibility to POP development.

A Cell Culture Model of Resistance Arteries.

The myoendothelial junction (MEJ), a unique signaling microdomain in small diameter resistance arteries, exhibits localization of specific proteins and signaling processes that can control vascular tone and blood pressure. As it is a projection from either the endothelial or smooth muscle cell, and due to its small size (on average, an area of ~1 µm2), the MEJ is difficult to study in isolation. However, we have developed a cell culture model called the vascular cell co-culture (VCCC) that allows for in vitro MEJ formation, endothelial cell polarization, and dissection of signaling proteins and processes in the vascular wall of resistance arteries. The VCCC has a multitude of applications and can be adapted to suit different cell types. The model consists of two cell types grown on opposite sides of a filter with 0.4 µm pores in which the in vitro MEJs can form. Here we describe how to create the VCCC via plating of cells and isolation of endothelial, MEJ, and smooth muscle fractions, which can then be used for protein isolation or activity assays. The filter with intact cell layers can be fixed, embedded, and sectioned for immunofluorescent analysis. Importantly, many of the discoveries from this model have been confirmed using intact resistance arteries, underscoring its physiological relevance.

Uterosacral Ligament Smooth Muscle Cell Apoptosis Is Increased in Women With Uterine Prolapse

The purpose of this study was to compare the smooth muscle content and apoptosis of the uterosacral ligament in women with and without uterine prolapse. Uterosacral ligaments were sampled in women with (n = 9) or without (n = 9) uterine prolapse undergoing hysterectomy. Smooth muscle of the uterosacral ligament was identified by immunohistochemistry. Digital image analysis was used to determine the fractional area of smooth muscle in the histologic cross sections. Apoptosis was assessed by terminal deoxynucelotidyl-transferase-mediated dUTP nick-end-labeling method. The fractional area of nonvascular smooth muscle in the uterosacral ligament of women with uterine prolapse was significantly decreased compared to women without prolapse (0.32 +/- 0.12 vs. 0.42 +/- 0.03, P = .02) and the apoptotic index was significantly higher compared to women without prolapse (0.20 +/- 0.06 vs. 0.08 +/- 0.04, P < .01). The fraction of smooth muscle in the uterosacral ligaments is significantly decreased, and the rate of apoptosis is higher in women with uterine prolapse compared to women without prolapse.

Vaginal smooth muscle cell apoptosis is increased in women with pelvic organ prolapse

To compare the smooth muscle content and apoptosis of the vagina in women with and without anterior vaginal wall prolapse. Vaginal tissues were sampled in women with (n = 6) or without (n = 6) anterior vaginal wall prolapse undergoing hysterectomy. Smooth muscle of the vagina was studied by immunohistochemistry. Digital image analysis was used to determine the fractional area of smooth muscle in the histologic cross-sections. Apoptosis was assessed by TUNEL assay. The fractional area of non-vascular smooth muscle in the vagina of women with anterior vaginal wall prolapse was significantly decreased compared to women without prolapse (0.36 +/- 0.12 vs. 0.16 +/- 0.12 P = 0.021) and the apoptotic index was significantly higher compared to women without prolapse (0.04 +/- 0.01 vs. 0.02 +/- 0.03, P = 0.041). The fraction of smooth muscle in the vagina is significantly decreased and the rate of apoptosis is higher in women with anterior vaginal wall prolapse compared to women without prolapse.

The effects of cyclical oestrogen on bladder and urethral structure and function

To determine the effects of cycling oestrogen in rabbits, as oestrogen is essential for physiological maintenance and integrity of the female urogenital tract. Changes in circulating oestrogen have marked effects on the bladder of experimental animals, with ovariectomy (Ovx) inducing smooth muscle (SM) and mucosal atrophy, increasing collagen synthesis and deposition, decreasing contractile function, mucosal and SM blood flow; oestrogen reverses these effects and increases bladder mass and SM density, primarily by stimulating angiogenesis and increasing blood flow. Twenty adult female New Zealand White rabbits were divided into five equal groups; group 1 served as the control group, and groups 2-5 had a bilateral Ovx. Group 2 received no oestradiol and was assessed 2 weeks after Ovx; groups 3-5 received 17-beta oestradiol from a subcutaneous slow-release tablet 2 weeks after Ovx, which remained in place for a subsequent 2-week period. Group 3 was then assessed after the 2 weeks on oestradiol. Groups 4 and 5 then had their oestradiol tablets removed for 2 weeks and group 4 was assessed after this period off oestradiol. Group 5 then received a new oestradiol tablet that was left in place for an additional 2 weeks. Both groups receiving oestrogen (3 and 5) had a statistically significantly greater bladder weight than both the control group and group 2. The volume fraction of SM paralleled the bladder weight, showing that oestrogen increased the volume fraction of SM whereas Ovx and low oestrogen decreased the SM fraction. The cross-sections of the urethra from groups 3 and 5 were significantly wider than those of either the control or group 1, also being consistent with the structural effects of oestrogen. Intra-arterial phenylephrine increased urethral pressure to a similar level in all groups. The urethral pressure response to intra-arterial acetylcholine shifted from contraction in the control to relaxation in the oestrogen-treated groups. Ovx resulted in a lower vascular density, whereas oestrogen resulted in a significant increase in vascular density (angiogenesis). Cyclical oestrogen had pronounced structural and pharmacological effects. Low oestrogen decreased the volume fraction of SM, increased collagen, and decreased vasculature, whereas oestrogen mediated a marked hypertrophy of the SM components, decreased the collagen component, and stimulated angiogenesis. Cyclical oestrogen also had marked effects on the responses to intra-arterial acetylcholine, shifting the response from contraction to relaxation.

Long-term effects of treatment with enalapril on the structure of mesenteric resistance arteries in New Zealand genetically hypertensive rats.

1. New Zealand genetically hypertensive (GH) rats were treated with enalapril (20 mg/kg per day in drinking fluids) from age 4-10 weeks; one group (GHex-enal) was then taken off enalapril and followed for 6 more weeks to see if the drug-induced changes in blood pressure (BP) and structure of mesenteric resistance arteries (MRA) were long lasting once the enalapril was withdrawn. Control groups consisted of untreated GH and their normotensive (N) control strain. 2. Tail-cuff BP in GH treated rats fell significantly to N BP levels during treatment. On cessation of treatment BP rose rapidly. At age 16 weeks BP, although at a hypertensive level (mean +/- s.e.m., GHex-enal, 210.8 +/- 4.7 mmHg), was still significantly below the GH controls (230 +/- 6.9, P < 0.05), but above the N control group (137 +/- 3, P < 0.001). 3. Left ventricular (LV) mass in GH rats was reduced by enalapril to that in N rats; at the end of the subsequent period without treatment it was still significantly lower than the GH control group, but also significantly above the N group (GHex-enal, 255 +/- 6; GH 306 +/- 11; N 179 +/- 3, mg/100 g bodyweight). 4. The large changes in media, lumen and media/lumen ratio seen after 6 weeks of treatment were not sustained over the subsequent non-treatment period. However, values in the GHex-enal group at 16 weeks were closer to those in the N16 control group. 5. The persisting effects on smooth muscle (SM) cell density and SM fraction of the media contributed to an increase in SM cell volume which was significantly greater than the N16 group (P < 0.01). The number of layers of SM in the media was less than in the GH16 control group and not different from the N16 controls. 6. In GH rats the effect of ACEI on PB, LV mass and MRA structure is relatively longlasting once treatment is withdrawn.

REMODELLING OF RESISTANCE ARTERIES BY TREATMENT WITH ENALAPRIL IN THE NEW ZEALAND GENETICALLY HYPERTENSIVE RAT

1. New Zealand genetically hypertensive (GH) rats were treated with enalapril from the age of 4 to 10 weeks and the effects of treatment on the structure of mesenteric resistance arteries (MRA) was measured by use of stereological analysis of stained sections and by myograph techniques. 2. Tail-cuff blood pressure (BP) was measured weekly and intra-arterial BP recorded just before MRA were either fixed by perfusion or mounted on a myograph. 3. Stereological techniques (Cavalieri and optical dissector) were used to determine media and lumen volume, fraction of smooth muscle (SM) within the media and SM cell density. For MRA mounted on the myograph, lumen diameter, media thickness, active tension and active pressure were recorded. 4. BP was significantly (P < 0.0001) lowered by enalapril throughout the experiment. Intraarterial BP and left ventricular (LV) mass were also significantly lower in the enalapril treated GH rats (P < 0.0001). 5. Stereological measurements showed that enalapril treatment significantly (P < 0.0001) reduced media volume by 50%, doubled lumen volume (P < 0.0001), reduced the fraction of SM in the media (P < 0.04), and had no effect on the number of SM cell layers or on SM cell density. 6. Myograph measurements showed a decrease in the ratio media thickness/lumen diameter which was accompanied by a decrease in maximum active tension and pressure development. 7. In the GH rat early treatment with enalapril causes a true loss of medial tissue that is not simply due to rearrangement of existing media around an enlarged lumen.(ABSTRACT TRUNCATED AT 250 WORDS)