Mechanical properties of the sciatic nerve following combined transplantation of analytically extracted acellular allogeneic nerve and adipose-derived mesenchymal stem cells

Purpose To investigate the effects of Chemically Extracted Acellular Nerves (CEANs) when combined with Adipose-Derived mesenchymal Stem Cell (ADSC) transplantation on the repair of sciatic nerve defects in rabbits. Methods A total of 71 six-month-old Japanese rabbit were used in this study. Twenty rabbits served as sciatic nerve donors, while the other 51 rabbits were randomly divided into Autologous Nerve Transplantation Group (ANT, n=17), CEAN group (n=17) and CEAN-ADSCs group (n=17). In all these groups, the rabbits left sciatic nerves were injured before the experiment, and the uninjured sciatic nerves on their right side were used as the control (CON). Electrophysiological tests were carried out and sciatic nerves were prepared for histomorphology and stretch testing at 24 weeks post-transplant. Results There were significant differences between ANT and Con groups in amplitude (AMP): P=0.031; motor nerve conduction velocity (MNCV): P=0.029; Maximum stress: P=0.029; and Maximum strain P=0.027. There were also differences between the CEAN and CEAN+ADSCs groups in AMP: P=0.026, MNCV: P=0.024; Maximum stress: P=0.025 and Maximum strain: P=0.030. No significant differences in these parameters were observed when comparing the ANT and CEAN+SACN groups (MNCV: P=0.071) or the CEAN and ANT groups (Maximum stress: P=0.069; Maximum strain P=0.077). Conclusion Addition of ADSCs has a significant impact on the recovery of nerve function, morphology, and tensile mechanical properties following sciatic nerve injury.(AU)

Relaxation incisions and tensile strength in the abdominal wall of pigs

Purpose: To analyze the resistance to medial traction of abdominal wall muscles, before and after performing relaxing incisions. Methods: Seventeen live pigs were used. After a median laparotomy, the handles were made in the rectus abdominis muscles (RAM) to fit the dynamometer. Step 1 (control phase): tensile strength measured without performing relaxant incisions. Step 2: A curvilinear relaxant incision was made on the anterior blade of the right RAM sheath and then the tensile strength was measured by the edge of the wound. The same procedure was adopted after incision of the left posterior blade. Step 3: Relaxing incisions were made in the right posterior and left anterior blade, so that both sides were left with a relaxing incision on both blades. Measurements of resistance were performed. Results: There was no statistically significant difference between the sides. On the right and left side, all treatments reduced the tensile strength when compared to each other and to the control. There was a reduction of 12% and 9.8% after incision of the anterior and posterior blade, respectively. Conclusion: Relaxing incisions reduced tensile strength in the ventral abdominal wall.(AU)

Effect of vitamin K1 supplementation on left colon healing in rats with extrahepatic biliary obstruction

PURPOSE: To evaluate the effects of vitamin K1 on wound healing in the left colon of rats with experimental biliary obstruction. METHODS: Sixteen male rats, divided into four groups of four animals each (L, M, LK, and MK), underwent colostomy followed by bowel suture in the left colon. Seven days before, animals in the L and LK groups had undergone common bile duct ligation. The animals in groups MK and LK received vitamin K1 supplementation. On day 7 after bowel suture, repeat laparotomy was performed for evaluation of colonic healing by burst pressure measurement and collection of samples for histopathological analysis. Changes in body weight were evaluated in the four groups. RESULTS: Weight loss was lower in animals supplemented with vitamin K. No significant differences were observed in burst pressure among the four groups (p>0.05). Histological analysis showed more hemorrhage and congestion in the biliary obstruction groups. Supplemented animals exhibited increased collagen formation and less edema and abscess formation. CONCLUSION: Vitamin K supplementation attenuated weight loss and improved colonic wound healing in rats.(AU)

Alloxan diabetes alters the tensile strength, morphological and morphometric parameters of abdominal wall healing in rats

To investigate the effects of alloxan diabetes on the abdominal wall healing of rats undergoing laparotomy. METHODS: Ninety-six male Wistar rats weighing between 200 and 300 grams, divided into two groups: non-diabetic group (G1) and another with untreated diabetes (G2). Three months after diabetes induction, the animals underwent a 5cm-long- laparotomy and 5.0 nylon monofilament suture. After the surgery, 12 animals from each group were euthanized on days 4, 14, 21 and 30 corresponding to the moments M1, M2, M3 and M4. In each moment a fragment of the abdominal wall containing the scar was removed for tensile strength measurement, histological and morphometric study. Clinical and biochemical parameters were also analyzed. RESULTS: G2 animals showed parameters compatible with severe diabetes and decreased plasma levels of insulin. The tensile strength in G2 was significantly smaller in M2 and M4, with a tendency to fall in the other two. Through light microscope, diabetic animals showed more difficulty to increase collagen density and contraction. G2 animals showed high cellularity of fibroblasts in later healing moments, with collagen thinning in M2 and M4. CONCLUSION: The abdominal wound healing in untreated diabetic animals was altered and led to a higher incidence of dehiscence and infections.(AU)

Does acute alcohol intoxication interfere with colonic anastomosis wound healing? a rat model of nondestructive colon trauma

PURPOSE: To evaluate the effects of acute alcohol intoxication on healing of colonic anastomosis. METHODS: Thirty-six rats were allocated into two groups. Animals in the alcohol (A) were given 2 mL of ethanol diluted in 0.9% saline solution to a concentration of 40% by gavage immediately before anesthesia, whereas control (C) animals received 2 mL of 0.9% saline solution via the same route. A colonic anastomosis was then performed in all animals. On postoperative days 1, 3, and 7, anastomotic breaking strength was assessed and histopathological examination was performed. Change in body weight and mortality were also evaluated. RESULTS: The median of anastomotic tensile strength on the postoperative day 1 was 0.09 Newtons for group A and 0.13 for group C. (p>0.05). The median of anastomotic tensile strength on the postoperative day 3 was 0.13 Newtons for group A and 0.17 for group C. (p>0.05). The median of anastomotic tensile strength on the postoperative day 7 was 0.30 Newtons for group A and 0.35 for group C. (p>0.05). There was no significant difference between the groups A and C, in the first, third or seventh POD (p>0.05), in any of the analyzed parameters. There were no statistical differences between groups in the weight. Three animals died, all from the group A. CONCLUSION: Acute alcohol intoxication did not interfere with wound healing of colonic anastomoses, although it caused early postoperative mortality.(AU)

Correlation between bursting pressure and breaking strength in colonic anastomosis

PURPOSE: To investigate the correlation between bursting pressure and breaking strength on the 7th postoperative day following left colonic anastomosis in rats. METHODS: Seventy rats were randomly divided into seven groups of ten animals each. All of the animals underwent segmental resection of the left colon and end-to-end anastomosis. The animals in groups I to VI underwent surgical laparoscopies with pneumoperitoneums using carbon dioxide or helium at pressures of 5, 12 or 20 mmHg. In Group VII, open laparotomy was performed. The animals were reoperated on postoperative day 7 to measure the bursting pressure and the breaking strength of the anastomosis. RESULTS: The anastomosis bursting pressure in 70 animals was 193.10±55.56 mmHg. There was no significant difference between the groups (p=0.786). The breaking strength of the anastomosis was 0.26±0.12 N. There was no significant difference between the groups (p=0.356). Pearson's correlation test showed a low correlation (r=0.231) lacking statistical significance (p=0.054). CONCLUSION: There was no correlation between the bursting pressure and breaking strength of left colonic anastomoses in rats on the 7th postoperative day.(AU)

Evaluation of the effects of carbon dioxide pneumoperitoneum on abdominal wall wound healing in rats undergoing segmental resection and anastomosis of the left colon / Avaliação dos efeitos do pneumoperitônio com dióxido de carbono na cicatrização da parede abdominal de ratos submetidos à ressecção segmentar e anastomose no cólon esquerdo

PURPOSE: To evaluate the influence of carbon dioxide pneumoperitoneum on abdominal wall wound healing in rats. METHODS: Eighty rats underwent laparotomy, segmental left colon resection, and anastomosis. The animals were divided into three experimental groups and one control group: EI = pneumoperitoneum for 30 minutes before laparotomy (n=20); EII = pneumoperitoneum for 30 minutes after abdominal closure (n=20); EIII = pneumoperitoneum for 30 minutes before laparotomy and 30 minutes after abdominal closure (n=20); C = control group, without pneumoperitoneum (n=20). In each group, 10 animals were killed 7 days and 10 animals 14 days postoperatively. A segment of the abdominal wall was resected and subjected to tensile strength testing. Another segment of abdominal muscle was used for histopathological analysis; the specimens were fixed in formalin and stained with hematoxylin and eosin. RESULTS: There were no differences in histopathology and tensile strength values among animals in the experimental and control groups 7 or 14 days after surgery. CONCLUSION: Under the present experimental conditions, carbon dioxide pneumoperitoneum did not interfere with abdominal wall wound healing.(AU)

OBJETIVO: Avaliar a influência do pneumoperitônio com dióxido de carbono na cicatrização da ferida operatória na parede abdominal de ratos. MÉTODOS: Oitenta ratos foram submetidos à laparotomia, ressecção de segmento do cólon esquerdo e anastomose. Os animais foram distribuídos em quatro grupos de 20 ratos, três experimentais e um controle: Grupo EI = pneumoperitônio por 30 minutos antes da laparotomia. Grupo EII = pneumoperitônio por 30 minutos após a laparorrafia. Grupo EIII = pneumoperitônio por 30 minutos antes da laparotomia e 30 após a laparorrafia. Grupo C = controle, sem pneumoperitônio. Realizou-se, em cada grupo, a eutanásia de 10 animais no 7º e no 14º dia pós-operatório. Um segmento da parede abdominal foi ressecado e submetido à medida da resistência. Outro segmento muscular abdominal foi destinado à análise histopatológica, as peças foram fixadas em formol e as lâminas coradas com hematoxilina e eosina. RESULTADOS: Não houve diferença, à histopatologia e na força de ruptura, entre os animais dos grupos experimentais e do controle no 7º ou 14º dia pós-operatório. CONCLUSÃO: Nas condições em que o experimento foi realizado, o pneumoperitônio com dióxido de carbono não interferiu na cicatrização da parede abdominal.(AU)

Effects of chitosan on healing and strength of colonic anastomosis in rats / Efeitos de quitosana na cicatrização e resistência de anastomose colônica em ratos

PURPOSE: To investigate whether chitosan application over colonic anastomosis line, provide reinforcement, and subsequently improve anastomotic healing. METHODS: Forty eight Wistar albino female rats were used and were randomly divided into four groups, 12 rats in each: The control groups (1 and 3) received no further treatment. The experimental groups (2 and 4) received chitosan application over the colonic anastomosis. After sacrifying rats at the end of the experiment (either on day three or on day seven, depending on the group), colonic bursting pressure, a hihydroxyproline level and histopathologic characteristics of the perianastomotic tissue were examined. RESULTS: At three days, chitosan and control groups had similar values for histopathologically. On day seven, chitosan group had significantly higher mean score of collagenization (p=0.007) and a significantly higher bursting pressure (p=0.038). CONCLUSION: Our study emphasizes the positive effect of chitosan in the process of collagenation in colonic anastomosis healing.(AU)

OBJETIVO: Investigar se a aplicação de quitosana em anastomose colônica promove resistência à tração e consequentemente a melhora na cicatrização. MÉTODOS: Foram utilizados 48 ratos Wistar fêmeas distribuídos em quatro grupos, 12 ratos em cada. Grupos controle (1 e 3) não receberam tratamento. Grupos experimento (2 e 4) receberam aplicação de quitosana na anastomose colônica. Após eutanásia após 3º ou 7º dias foram examinadas a tensão, o nível de hidroxiprolina e aspectos histopatológicos da anastomose. RESULTADOS: Após três dias os grupos controle e quitosana não apresentaram alterações histopatológicas. No sétimo dia o grupo quitosana apresentou significante elevação do escore de colagenização (p=0,007) e da tensão de ruptura (p=0,038). CONCLUSÃO: A quitosana apresentou bons resultados nos processos de colagenização e cicatrização de anastomose colônica.(AU)

Estudo comparativo entre as telas de poliéster com colágeno e politetrafluoretileno no reparo de defeitos produzidos na parede abdominal de ratos / Comparative study between meshes of polyester with collagen and polytetrafluoroethylene in the repair of defects produced in abdominal wall of rats

PURPOSE: To study the intraperitoneal use of polyester with collagen and polytetrafluoroethylene meshes in the correction of total ventral wall defects in rats. METHODS: Thirty two rats were evaluated and divided randomly into four groups and underwent laparotomy and preparation of total defects of the abdominal wall. Next, the correction of the defect with the intraperitoneal placement of the chosen mesh was performed. The rats were submitted to euthanasia at 30 and 90 days after surgery. Were analyzed the macroscopic adhesions and microscopic aspects, and applied stress rupture test RESULTS: All animals showed intraperitoneal adhesions in varying degrees, with no statistical significance difference. There was no difference also between groups in the evaluation of stress rupture tests. On the microscopic aspect, the A30 group had less inflammatory reaction and less formation of granulomas and foreign body reaction that the B30 group, with significant difference. CONCLUSIONS: There was no difference in intraperitoneal adhesion and tensile rupture strength among groups. Group B30 presented granulomatous inflammatory reaction at the site of mesh attachment to the wall significantly higher than the A30.(AU)

OBJETIVO: Estudar comparativamente o uso intraperitoneal das telas de poliéster com colágeno e politetrafluoretileno na correção de defeitos totais da parede ventral em ratos. MÉTODOS: Foram avaliados 32 ratos distribuídos em quatro grupos aleatórios e submetidos à laparotomia e confecção de defeitos totais da parede abdominal. Em seguida, foi realizada a correção do defeito com a colocação intraperitoneal das telas. A eutanásia ocorreu aos 30 e 90 dias do pós-operatório. Foram analisadas as aderências macroscópicas, aspectos microscópicos e aplicado teste de tensão de ruptura. RESULTADOS: Todos os animais apresentaram aderências abdominais intraperitoneais em vários graus, sem significância estatística. Não houve diferença entre os grupos na avaliação dos testes de tensão de ruptura. Na análise microscópica o grupo A30 teve menor reação inflamatória e formação de granulomas, e menor reação do tipo corpo estranho quando comparado ao grupo B30, com resultados significativos. CONCLUSÕES: Não houve diferença significativa entre os grupos tanto em relação à formação de aderências intraperitoneais quanto à tensão de ruptura. O grupo B30 apresentou reação inflamatória e formação granulomatosa no local de fixação na parede significativamente maior que o grupo A30.(AU)

Effects of abdominal sepsis in the healing of abdominal wall: experimental study in rats / Efeitos da sepse abdominal na cicatrização de parede abdominal: estudo experimental em ratos

PURPOSE: To evaluate the influence of sepsis in the process of wound healing in the abdominal wall. METHODS: 40 rats divided into two groups of twenty animals: group of study (E) - septic, and the control group (C) - not septic. The two groups were divided into subgroups of 10 to be killed on the third day (n = 10) or seventh (n = 10) postoperative. Sepsis was induced by ligation and puncture of the cecum. We performed also the section and anastomosis in left colon. The synthesis of the abdominal wall was made with 3-0 silk thread. On the day of re-laparotomy, the abdominal wall was removed for analysis of the breaking strength and histopathological analysis. RESULTS: The mean breaking strength was at third day: E group (1.44 ± 1.22) and C group (0.35 ± 0.46). At seventh day the mean breaking strength was: E group (13.01 ± 7.09) and C group (11.66 ± 7.38). There was statistical difference in tensile strength. E group at third day with control group (p = 0.019). CONCLUSION: The induction of peritoneal sepsis reduced the breaking strength of the abdominal wall on the third day after surgery.(AU)

OBJETIVO: Avaliar a influência da sepse no processo de cicatrização de feridas na parede abdominal. MÉTODOS: 40 ratos divididos em dois grupos de vinte animais: grupo de estudo (E) - séptico, e grupo controle (C) - não séptico. Os dois grupos foram divididos em subgrupos de 10 sendo os animais mortos no terceiro (n = 10) ou sétimo dia (n = 10) pós-operatório. A sepse foi induzida por ligadura e punção do ceco. Foi realizada também a secção e anastomose em cólon esquerdo. A síntese da parede abdominal foi feita com fio de seda 3-0. No dia da re-laparotomia, a parede abdominal foi retirado para análise da força de ruptura e análise histopatológica. RESULTADOS: A força média de ruptura foi: no terceiro dia, grupo E (1,44 ± 1,22) e grupo C (0,35 ± 0,46); no sétimo dia, grupo E (13,01 ± 7,09) e grupo C (11,66 ± 7,38). Houve diferença estatística na resistência à tração do grupo E do terceiro dia quando comparado ao grupo controle (p = 0,019). CONCLUSÃO: A indução de sepse peritoneal reduziu a resistência à ruptura da parede abdominal no terceiro dia após a cirurgia.(AU)