Effects of photobiomodulation with blue Light Emitting Diode (LED) on the healing of skin burns.

The management of skin burns is still challenging. Among the therapeutic methods used, there are topical treatments with pharmacological and herbal agents, low-intensity therapeutic ultrasound, use of biomaterials, reconstructive techniques and photobiomodulation therapy. The aim of this study was to evaluate the effects of photobiomodulation with blue Light Emitting Diode (LED) on burn healing. Fifty Wistar rats were divided into control (CTRL) (n = 25) and blue LED (LED) (n = 25), with subgroups (n = 5) for each time of euthanasia (7, 14, 21, 28 and 32 days). Treated animals were daily irradiated (470 nm, 1W, 0.44 W/cm2, 50 J/cm2). Clinical evaluations were performed and the Wound Retraction Index (WRI) was determined. Histological sections were submitted to hematoxylin-eosin, toluidine blue and the immunohistochemical technique, with anti-α-SMA and anti-TGF-ß1 antibodies. All data were directly collected by previously calibrated evaluators in a blind manner. The values were included in a statistical program. For all statistical tests used, 5% significance level (p < 0.05) was considered. No statistically significant differences in WRI between groups were observed (p > 0.05). Re-epithelialization was higher using LED at 7 and 14 days (p < 0.05) and greater amount of inflammatory cells was observed at 7 days (p = 0.01). With LED at 21 and 32 days, greater number of mast cells were observed (p < 0.05), as well as smaller number of myofibroblasts at 14, 21, 28 and 32 days (p < 0.05) and lower percentage of TGF-ß1 positive cells in the conjunctiva at 7, 14 and 21 days (p < 0.05). Negative correlations were observed in LED between the percentage of TGF-ß1 in the epithelium and the mean number of inflammatory cells and number of myofibroblasts (p < 0.05). The results suggest that, depending on the period, blue LED can modulate the healing processes of third-degree skin burns, such as re-epithelialization, inflammatory response, mast cell concentration, myofibroblast differentiation and TGF-ß1 immunoexpression. Despite these effects, this therapy does not seem to have significant influence on the retraction of these wounds. Future studies, using different protocols, should be carried out to expand the knowledge about the photobiomodulatory mechanisms of this type of light in the healing process.

Pentoxifylline/Chitosan Films on Wound Healing: In Vitro/In Vivo Evaluation.

This study aimed to develop films of chitosan (CSF) associated with pentoxifylline (PTX) for healing cutaneous wounds. These films were prepared at two concentrations, F1 (2.0 mg/mL) and F2 (4.0 mg/mL), and the interactions between the materials, structural characteristics, in vitro release, and morphometric aspects of skin wounds in vivo were evaluated. The formation of the CSF film with acetic acid modifies the polymeric structure, and the PTX demonstrates interaction with the CSF, in a semi-crystalline structure, for all concentrations. The release for all films was proportional to the concentration, with two phases: a fast one of ≤2 h and a slow one of >2 h, releasing 82.72 and 88.46% of the drug after 72 h, being governed by the Fickian diffusion mechanism. The wounds of the mice demonstrate a reduction of up to 60% in the area on day 2 for F2 when compared to CSF, F1, and positive control, and this characteristic of faster healing speed for F2 continues until the ninth day with wound reduction of 85%, 82%, and 90% for CSF, F1, and F2, respectively. Therefore, the combination of CSF and PTX is effective in their formation and incorporation, demonstrating that a higher concentration of PTX accelerates skin-wound reduction.

Morphological, biochemical and histological effects of aqueous extracts of peanut (Arachis hypogaea) on swiss mice in different diets.

PURPOSE: To evaluate the morphological, biochemical, and histological effects of aqueous extracts of peanut (skinless and added to 1% skin) in Swiss mice submitted to a high-fat diet. METHODS: Forty male Swiss mice were divided into four groups (n=10 per group): GI) normocaloric diet; GII) high-fat diet; GIII) high-fat diet + 0.5 mL of peanut extract; GIV) high-fat diet + 0.5 mL of peanut extract + 1% peanut skin. The animals were weighed weekly and euthanized after 12 weeks for histopathological and biochemical analyses. The study was approved by the Animal Use Ethics Committee. RESULTS: The animals in the GIV group had higher body weight when compared to the other ones. Increase in total cholesterol in GIII, increase in blood glucose in groups GII, GIII and GIV, decrease in serum low-density lipoprotein (LDL) concentration in groups GI and GIV and increase in serum concentration of C-reactive protein in GII were seen. The presence of vacuolar fat deposits was found in animal livers from GII. CONCLUSIONS: The extracts improved the plasma concentrations of animals that received a high-fat diet, including preventing morphological damage to liver tissue. These benefits were enhanced by the association of peanut shells with the extract.

Chondroprotective effect of melatonin and strontium ranelate in animal model of osteoarthritis.

PURPOSE: To analyze the action of strontium ranelate (SR) and melatonin in isolation or in association in knees, liver and kidneys of rats Wistar with induced osteoarthritis (OA). METHODS: Thirty male rats were induced to OA through an anterior cruciate ligament transection (ACLT), and treated with melatonin and SR in isolation or in association. Morphological, histopathological, histochemical and morphometric analysis were realized of the structure of the articular capsule, as well as histopathological analysis of liver and kidneys from the animals. RESULTS: The experimental model was successful. The association of the drugs presented chondroprotective pharmacodynamics. However, more successful results were identified from analysis of animals in which received melatonin in isolation, regarding biochemical parameters of glutamic oxalacetic transaminase. The prepared slide samples of liver and kidneys from groups submitted to the isolated use of SR and melatonin or the association of these drugs presented no differences, when compared to the control group. DISCUSSION: The administration of the drugs presented chondroprotective effect and prevented from the aggravation of articulate damages, and was not capable of modifying the histology of liver or kidneys. This finding suggests a safe association for the treatment of OA, however it requires further investigation in order to expand therapeutic perspectives regarding improvements of the quality of life of individuals in our society.

Morphological, biochemical and histological effects of aqueous extracts of peanut (Arachis hypogaea) on swiss mice in different diets

ABSTRACT Purpose: To evaluate the morphological, biochemical, and histological effects of aqueous extracts of peanut (skinless and added to 1% skin) in Swiss mice submitted to a high-fat diet. Methods: Forty male Swiss mice were divided into four groups (n=10 per group): GI) normocaloric diet; GII) high-fat diet; GIII) high-fat diet + 0.5 mL of peanut extract; GIV) high-fat diet + 0.5 mL of peanut extract + 1% peanut skin. The animals were weighed weekly and euthanized after 12 weeks for histopathological and biochemical analyses. The study was approved by the Animal Use Ethics Committee. Results: The animals in the GIV group had higher body weight when compared to the other ones. Increase in total cholesterol in GIII, increase in blood glucose in groups GII, GIII and GIV, decrease in serum low-density lipoprotein (LDL) concentration in groups GI and GIV and increase in serum concentration of C-reactive protein in GII were seen. The presence of vacuolar fat deposits was found in animal livers from GII. Conclusions: The extracts improved the plasma concentrations of animals that received a high-fat diet, including preventing morphological damage to liver tissue. These benefits were enhanced by the association of peanut shells with the extract.

Bicontinuous microemulsions containing Melaleuca alternifolia essential oil as a therapeutic agent for cutaneous wound healing.

The Melaleuca alternifolia essential oil (MEO) has been widely used due to its healing and antimicrobial action. Its incorporation into drug delivery systems is a reality, and numerous studies have already been developed for this purpose. In this regard, the aim of this work was to develop, characterize, and evaluate the in vivo pharmacological activity of bicontinuous microemulsions (BME) containing MEO. Through diagram construction, a formulation consisting of Kolliphor® HS 15 (31.05%), Span® 80 (3.45%), isopropyl myristate (34.5%), and distilled water (31%) was selected and MEO was incorporated in the proportion of 3.45% (v/v). Morphological analysis characterization confirms that the system studied herein is a BME. The evaluated formulation showed physicochemical characteristics that allow its topical use. Rheologically, samples were characterized as pseudo-plastic non-Newtonian thixotropic fluids. The chromatographic method developed is in accordance with the current recommendations. The extraction method used assured a 100% recovery of the pharmacological marker (terpinen-4-ol). In vivo studies suggest that BME loaded with MEO may contribute to the healing process of skin wounds. In addition, it demonstrated antibacterial activity for Gram-positive and Gram-negative bacteria. Therefore, the BME system loaded with MEO is promising as a healing and antimicrobial agent for skin wounds.Graphical abstract.

Photobiomodulation of red and green lights in the repair process of third-degree skin burns.

The aim of this study was to evaluate the photobiomodulation of red and green lights in the repair process of third-degree skin burns in rats through clinicopathological and immunohistochemical parameters. Sixty male Wistar rats were divided into three groups: control (CTRL) (n = 20), red LED (RED) (n = 20), and green LED (GREEN) (n = 20), with subgroups (n = 5) for each time of euthanasia (7, 14, 21, and 28 days). Daily applications in RED (λ630 ± 10 nm, 300 mW) and GREEN groups (λ520 ± 30 nm, 180 mW) were performed at four points of the wound (total 36 J/cm2 in RED and 240 J/cm2 in GREEN). After euthanasia, the wound retraction index (WRI) was evaluated. In histological sections, the re-epithelialization degree, the angiogenic index (AI), and the amount of myofibroblasts in wounds were analyzed. At 14 and 21 days, the RED group induced higher re-epithelialization and WRI compared to CTRL (p > 0.05) and GREEN groups (p < 0.05). At 7 and 14 days, greater AI were observed in the GREEN group, with significant difference in relation to CTRL group at 7 days (p < 0.05). At 21 and 28 days, a trend was observed for greater amount of myofibroblasts in the GREEN group, with significant difference in relation to CTRL group at 21 days (p < 0.05). The results suggest greater potential of the green light to stimulate angiogenesis in the initial periods and myofibroblastic differentiation in the final periods of the repair of third-degree skin burns. Red light may stimulate further re-epithelialization and wound retraction, especially in advanced repair phases.

Fecal peritonitis in aging rat model. Therapeutic response to different antibiotic strategies.

PURPOSE: To evaluate the response of aging rats with sepsis to two different antibiotic regimens. METHODS: The study was conducted with 30 aging rats (18 month-old) with autologous feces peritonitis. The animals were divided into three groups: Group 0 received no therapeutic intervention (control), while Group 1 received a single dose of 40 mg/kg meropenem and Group 2 received a single dose of 20 mg/kg moxifloxacin. The intervention in both Groups was made 6 hours after induction of peritonitis. The animals were followed up to 15 days for evaluating morbidity and mortality. The weights at baseline were similar in all groups. RESULTS: At the end of follow-up, weight loss was significantly greater (p=0.0045) in Group 0 (non-intervention controls). Culture from a blood sample at the end of follow-up was positive in all the animals in Group 0, in two animals in Group 1 and in four animals in Group 2. Morbidity/mortality was significantly higher in Group 0 compared to both Groups 1 and 2 (p=0.003) but the scores were not significantly different between Groups 1 and 2 (p=0.6967). CONCLUSION: Both antibiotic regimens rendered promising results for the treatment of fecal peritonitis.

Fecal peritonitis in aging rat model. Therapeutic response to different antibiotic strategies

Abstract Purpose: To evaluate the response of aging rats with sepsis to two different antibiotic regimens. Methods: The study was conducted with 30 aging rats (18 month-old) with autologous feces peritonitis. The animals were divided into three groups: Group 0 received no therapeutic intervention (control), while Group 1 received a single dose of 40 mg/kg meropenem and Group 2 received a single dose of 20 mg/kg moxifloxacin. The intervention in both Groups was made 6 hours after induction of peritonitis. The animals were followed up to 15 days for evaluating morbidity and mortality. The weights at baseline were similar in all groups. Results: At the end of follow-up, weight loss was significantly greater (p=0.0045) in Group 0 (non-intervention controls). Culture from a blood sample at the end of follow-up was positive in all the animals in Group 0, in two animals in Group 1 and in four animals in Group 2. Morbidity/mortality was significantly higher in Group 0 compared to both Groups 1 and 2 (p=0.003) but the scores were not significantly different between Groups 1 and 2 (p=0.6967). Conclusion: Both antibiotic regimens rendered promising results for the treatment of fecal peritonitis.

Brain damage and congenital cataract due to autogenously fecal peritonitis in pregnant Wistar rats.

PURPOSE: To investigate the morphological aspects of brain and eyes in newborn rats whose mother underwent autogenously fecal peritonitis. METHODS: Four pregnant rats that underwent fecal peritonitis, with a 10% fecal suspension in dose of 4 ml per kilogram received two antimicrobial treatments: 1. intraperitoneal moxifloxacin and dexamethazone; and 2. Intravenous meropenem. After head inspection, the brain consistencies and the eyes belonging to all offspring were analyzed. RESULTS: The brains of newborn from rats that received 4 ml/kg of 10% suspension of feces showed, significantly smaller and less than the firm consistency of those in the control group. Congenital cataract was observed in 9 (34.6%). No cataract was observed in the 20 newborn rats from the mothers that received the combination of moxifloxacin and dexamethasone. Cataract could be observed in three (13.6%) offspring from mothers that received meropenem. CONCLUSIONS: Peritonitis can produce brain damage and congenital cataract in rats. The translation to humans is that intra abdominal infection in pregnant women may be associated with damage in brain and eye structures of their concepts. This can be averting using the adequate early therapeutically approach.

Severe autogenously fecal peritonitis in ageing Wistar rats. Response to intravenous meropenem.

PURPOSE: To evaluate the treatment outcome of severe peritonitis in rats with increasing age. METHODS: Thirty Wistar rats stratified in three groups: group I - six month-old; group II - 12 month-old; and group III - 18 month-old, underwent autogenously fecal peritonitis (6 ml/kg rat), and were treated with intravenous meropenem. The survival animals were followed-up for 45 days. The variables were expressed by their mean and standard error of the mean (SEM). p<0.05 was used for rejecting the null hypothesis. The study was approved by the Ethics Committee. RESULTS: There was a significant increase in the mortality and morbidity in elderly rats. Of interest, even among young survival rats presenting with severe residual abscesses both in the abdomen and thorax cavities, they present an almost normal life. CONCLUSIONS: The treatment of severe autogenously fecal peritonitis with intravenous meropenem reached reasonable results in rats with six and twelve months of age, even considering residual abscesses on abdomen and thorax cavities. However, the great majority (80%) of elderly rats could not overcome the initial severe infectious challenge, proving that ageing is a very important risk factor for impairing immune response. Thus, sepsis remains a challenging situation, especially in elderly.

Alcohol extract of Schinu sterebinthifolius raddi (anacardiaceae) as a local antimicrobial agent in severe autogenously fecal peritonitis in rats.

PURPOSE: To develop an alcoholic extract of the inner bark of the Schinus terebinthifolius raddi and to test its impact on autogenously fecal peritonitis in Wistar rats. METHODS: The inner bark of the Schinus terebinthifolius raddi was kept for seven days in 70% ethanol alcohol. The total elimination of the solvent was performed in a rotary evaporator under reduced pressure at 55-60°C. Four milliliter of this extract was injected, after 24 h, into the abdominal cavity of six out of eight survival rats that underwent autogenously fecal peritonitis with five milliliter of 10% filtered fecal suspension. They were clinically followed up for 45 days when they were euthanized. The necropsy findings (inventory) of the abdominal and thorax cavities were inspected and the main findings were recorded and photographed. The investigation was approved by the Ethics Committee. RESULTS: Two out of six survival rats that were critically ill after 24 h died within the 12 h after the extract injection into the abdominal cavity. Four rats that were also critically ill recovered and gradually became healthy, eating well, regaining weight and moving normally in the cage. At 45 days post severe peritonitis the necropsy findings revealed few signs of residual infection on the abdominal and thorax cavities. There were no bowel adhesions. CONCLUSION: The impact of alcoholic extract of the inner bark of the Schinus terebinthifolius raddi was considered very positive and promising as natural local antiseptic against very severe peritonitis in Wistar rats.

Severe autogenously fecal peritonitis in ageing Wistar rats. Response to intravenous meropenem

PURPOSE: To evaluate the treatment outcome of severe peritonitis in rats with increasing age. METHODS: Thirty Wistar rats stratified in three groups: group I - six month-old; group II - 12 month-old; and group III - 18 month-old, underwent autogenously fecal peritonitis (6 ml/kg rat), and were treated with intravenous meropenem. The survival animals were followed-up for 45 days. The variables were expressed by their mean and standard error of the mean (SEM). p<0.05 was used for rejecting the null hypothesis. The study was approved by the Ethics Committee. RESULTS: There was a significant increase in the mortality and morbidity in elderly rats. Of interest, even among young survival rats presenting with severe residual abscesses both in the abdomen and thorax cavities, they present an almost normal life. CONCLUSIONS: The treatment of severe autogenously fecal peritonitis with intravenous meropenem reached reasonable results in rats with six and twelve months of age, even considering residual abscesses on abdomen and thorax cavities. However, the great majority (80%) of elderly rats could not overcome the initial severe infectious challenge, proving that ageing is a very important risk factor for impairing immune response. Thus, sepsis remains a challenging situation, especially in elderly. .

Severe autogenously fecal peritonitis in Wistar rats with permanent bilateral carotid occlusion. Response to intra peritoneal moxifloxacin combined with dexamethasone.

PURPOSE: To evaluate the treatment outcome of severe peritonitis in rats submitted to permanent bilateral carotid occlusion (PBCO). METHODS: Sixteen Wistar rats (mean age of 8.5 months) with PBCO underwent autogenously fecal peritonitis, and were treated with moxifloxacin combined with dexamethasone, and followed-up for 45 days. Ten rats (mean age five months) without PBCO were used as a control group. The variables were expressed by their mean and standard error of the mean (SEM). p<0.05 was used for rejecting the null hypothesis. The study was approved by the Ethics Committee. RESULTS: There was a significant increase (p=0.0002) in the mortality and morbidity in older rats that underwent PBCO (study group). However, even among the survival rats presenting with severe residual abscesses both in the abdomen and thorax cavities, they present an almost normal life. CONCLUSIONS: The treatment of severe autogenously fecal peritonitis with intraperitoneal moxifloxacin combined with dexamethasone was very effective in young rats without permanent bilateral carotid occlusion. The treatment reached reasonable results in older rats with PBCO, even considering residual abscesses on abdomen and thorax. Older age was the greater risk factor for the outcome of the treatment of severe peritonitis. Sepsis remains a challenging situation, especially in elderly.

Severe autogenously fecal peritonitis in Wistar rats with permanent bilateral carotid occlusion. Response to intra peritoneal moxifloxacin combined with dexamethasone

To evaluate the treatment outcome of severe peritonitis in rats submitted to permanent bilateral carotid occlusion (PBCO). METHODS: Sixteen Wistar rats (mean age of 8.5 months) with PBCO underwent autogenously fecal peritonitis, and were treated with moxifloxacin combined with dexamethasone, and followed-up for 45 days. Ten rats (mean age five months) without PBCO were used as a control group. The variables were expressed by their mean and standard error of the mean (SEM). p<0.05 was used for rejecting the null hypothesis. The study was approved by the Ethics Committee. RESULTS: There was a significant increase (p=0.0002) in the mortality and morbidity in older rats that underwent PBCO (study group). However, even among the survival rats presenting with severe residual abscesses both in the abdomen and thorax cavities, they present an almost normal life. CONCLUSIONS: The treatment of severe autogenously fecal peritonitis with intraperitoneal moxifloxacin combined with dexamethasone was very effective in young rats without permanent bilateral carotid occlusion. The treatment reached reasonable results in older rats with PBCO, even considering residual abscesses on abdomen and thorax. Older age was the greater risk factor for the outcome of the treatment of severe peritonitis. Sepsis remains a challenging situation, especially in elderly.

Translational realistic expectations of chronic cerebral hypoxemia in rat model after bilateral commom carotid artery ligation. Neurocognitive aspects.

PURPOSE: To evaluate the effects of chronic cerebral hypoxia on memory of rats submitted to bilateral common carotid artery ligation (BCCL). METHODS: Every each week, for 16 weeks, 31 rats were tested for memory using a water and land mazes and compared with 30 normal rats (control group A). The variables were expressed by their mean and standard error of the mean (SEM). p<0.05 was used for rejecting the null hypothesis. The study was approved by the Ethics Committee for animal investigation. RESULTS: There was a significant increase in the latency time, in the survival water and land mazes, after four weeks (study group B) follow-up. However, without any medication or therapeutically induced measures, after 16 weeks (study group C) follow-up the latency mean times tend to be similar to control group (A) in the neurocognitive tests. CONCLUSIONS: Neurocognitive deficits after 16 weeks post-operative follow-up of rats that underwent bilateral common carotid artery ligation is a natural adaptive phenomenon. Thus, is not realistic to allow translational information from this animal model for therapeutically approaches aiming at to prevent, or to improve brain damage in human beings suffering from chronic deprivation of adequate blood supply.

Translational realistic expectations of chronic cerebral hypoxemia in rat model after bilateral commom carotid artery ligation. Neurocognitive aspects

To evaluate the effects of chronic cerebral hypoxia on memory of rats submitted to bilateral common carotid artery ligation (BCCL). METHODS: Every each week, for 16 weeks, 31 rats were tested for memory using a water and land mazes and compared with 30 normal rats (control group A). The variables were expressed by their mean and standard error of the mean (SEM). p<0.05 was used for rejecting the null hypothesis. The study was approved by the Ethics Committee for animal investigation. RESULTS: There was a significant increase in the latency time, in the survival water and land mazes, after four weeks (study group B) follow-up. However, without any medication or therapeutically induced measures, after 16 weeks (study group C) follow-up the latency mean times tend to be similar to control group (A) in the neurocognitive tests. CONCLUSIONS: Neurocognitive deficits after 16 weeks post-operative follow-up of rats that underwent bilateral common carotid artery ligation is a natural adaptive phenomenon. Thus, is not realistic to allow translational information from this animal model for therapeutically approaches aiming at to prevent, or to improve brain damage in human beings suffering from chronic deprivation of adequate blood supply.

Alcohol extract of Schinu sterebinthifolius raddi (anacardiaceae) as a local antimicrobial agent in severe autogenously fecal peritonitis in rats

PURPOSE: To develop an alcoholic extract of the inner bark of the Schinus terebinthifolius raddi and to test its impact on autogenously fecal peritonitis in Wistar rats. METHODS: The inner bark of the Schinus terebinthifolius raddi was kept for seven days in 70% ethanol alcohol. The total elimination of the solvent was performed in a rotary evaporator under reduced pressure at 55-60°C. Four milliliter of this extract was injected, after 24 h, into the abdominal cavity of six out of eight survival rats that underwent autogenously fecal peritonitis with five milliliter of 10% filtered fecal suspension. They were clinically followed up for 45 days when they were euthanized. The necropsy findings (inventory) of the abdominal and thorax cavities were inspected and the main findings were recorded and photographed. The investigation was approved by the Ethics Committee. RESULTS: Two out of six survival rats that were critically ill after 24 h died within the 12 h after the extract injection into the abdominal cavity. Four rats that were also critically ill recovered and gradually became healthy, eating well, regaining weight and moving normally in the cage. At 45 days post severe peritonitis the necropsy findings revealed few signs of residual infection on the abdominal and thorax cavities. There were no bowel adhesions. CONCLUSION: The impact of alcoholic extract of the inner bark of the Schinus terebinthifolius raddi was considered very positive and promising as natural local antiseptic against very severe peritonitis in Wistar rats. .

Autogenous fecal peritonitis in Wistar rats with permanent bilateral carotid occlusion: morbidity, mortality and microbiological response.

PURPOSE: To investigate morbidity, mortality and microbiological response to fecal peritonitis induced in Wistar rats with permanent bilateral carotid ligation (PBCL). METHODS: Fecal peritonitis was induced in 30 rats, with 10 animals in each group: Group1 - normal young animals; Group2 - normal mature animals; and Group3 - rats with PBCL after four months postoperative follow-up. Peritonitis was induced with 10% stool suspension. Morbidity and mortality were evaluated. The survival animals after seven days were euthanized for tests. For microbiological studies blood were collected from the carotids and right ventricle; and fragments of lung and peritoneum. RESULTS: The morbidity and mortality of young animals were significantly lower than in mature animals with and without PBCL. There was no difference in morbidity and mortality among mature rats with and without PBCL. The diversity of microorganisms producing septicemia was similar to native micro biota of the large bowel. CONCLUSIONS: The immune response was more efficient in young animals, represented by significant less morbidity and no natural mortality. PBLC did not affect morbidity and mortality in mature rats. The immune response to fecal peritonitis has age as an independent predictor.

Autogenous fecal peritonitis in Wistar rats with permanent bilateral carotid occlusion: morbidity, mortality and microbiological response

PURPOSE: To investigate morbidity, mortality and microbiological response to fecal peritonitis induced in Wistar rats with permanent bilateral carotid ligation (PBCL). METHODS: Fecal peritonitis was induced in 30 rats, with 10 animals in each group: Group1 - normal young animals; Group2 - normal mature animals; and Group3 - rats with PBCL after four months postoperative follow-up. Peritonitis was induced with 10% stool suspension. Morbidity and mortality were evaluated. The survival animals after seven days were euthanized for tests. For microbiological studies blood were collected from the carotids and right ventricle; and fragments of lung and peritoneum. RESULTS: The morbidity and mortality of young animals were significantly lower than in mature animals with and without PBCL. There was no difference in morbidity and mortality among mature rats with and without PBCL. The diversity of microorganisms producing septicemia was similar to native micro biota of the large bowel. CONCLUSIONS: The immune response was more efficient in young animals, represented by significant less morbidity and no natural mortality. PBLC did not affect morbidity and mortality in mature rats. The immune response to fecal peritonitis has age as an independent predictor.