Doxycycline hyclate may damage testicular germinal epithelium in Wistar rats

Broad-spectrum antimicrobial doxycycline acts as an inhibitor of protein synthesis and it is widely used in the clinical treatment of various infections by microorganisms that are sensitive to the drug, as well as in animal feed. Its liposolubility guarantees its high tissue bioavailability, being associated with several biochemical changes in the organism and potentially adverse effects on reproduction. This study aims to evaluate the effects of the action of doxycycline on spermatogenesis to provide a complete analysis of the tubular and interstitial compartments and to identify possible changes in the testicular parenchyma. Adult male Wistar rats were divided into three groups: one control (water), and two treated with doxycycline at the doses of 10mg/kg and 30mg/kg, for 30 days. After euthanasia and sample processing, the following parameters were evaluated: a) tubular diameter and height of the seminiferous epithelium; b) volumetric proportions (%) and volumes (mL) of the components of the testicular parenchyma; c) counting testicular germ cell populations; d) evaluation of cell viability. The results of the comparative evaluation between the experimental groups demonstrated a significant increase in the diameter and area of the tubular lumen and a reduction in the count of spermatogonia in the experimental group that received doxycycline hyclate at a dose of 30mg/kg. In the same experimental group, an increase in the overall yield of spermatogenesis was found as a consequence of the increase in the mitotic index.

Peptides from Animal Origin: A Systematic Review on Biological Sources and Effects on Skin Wounds.

BACKGROUND: Skin wounds are closely correlated with opportunistic infections and sepsis risk. Due to the need of more efficient healing drugs, animal peptides are emerging as new molecular platforms to accelerate skin wound closure and to prevent and control bacterial infection. AIM: The aim of this study was to evaluate the preclinical evidence on the impact of animal peptides on skin wound healing. In addition, we carried out a critical analysis of the studies' methodological quality. Main Methods. This systematic review was performed according to the PRISMA guidelines, using a structured search on the PubMed-Medline, Scopus, and Web of Science platforms to retrieve studies published until August 25, 2020 at 3 : 00 pm. The studies included were limited to those that used animal models, investigated the effect of animal peptides with no association with other compounds on wound healing, and that were published in English. Bias analysis and methodological quality assessments were examined through the SYRCLE's RoB tool. RESULTS: Thirty studies were identified using the PRISMA workflow. In general, animal peptides were effective in accelerating skin wound healing, especially by increasing cellular proliferation, neoangiogenesis, colagenogenesis, and reepithelialization. Considering standardized methodological quality indicators, we identified a marked heterogeneity in research protocols and a high risk of bias associated with limited characterization of the experimental designs. CONCLUSION: Animal peptides show a remarkable healing potential with biotechnological relevance for regenerative medicine. However, rigorous experimental approaches are still required to clearly delimit the mechanisms underlying the healing effects and the risk-benefit ratio attributed to peptide-based treatments.

Plant Extracts in the Bone Repair Process: A Systematic Review.

Bone lesions are an important public health problem, with high socioeconomic costs. Bone tissue repair is coordinated by an inflammatory dynamic process mediated by osteoprogenitor cells of the periosteum and endosteum, responsible for the formation of a new bone matrix. Studies using antioxidant products from plants for bone lesion treatment have been growing worldwide. We developed a systematic review to compile the results of works with animal models investigating the anti-inflammatory activity of plant extracts in the treatment of bone lesions and analyze the methodological quality of the studies on this subject. Studies were selected in the PubMed/MEDLINE, Scopus, and Web of Science databases according to the PRISMA statement. The research filters were constructed using three parameters: animal model, bone repair, and plant extracts. 31 full-text articles were recovered from 10 countries. Phytochemical prospecting was reported in 15 studies (48.39%). The most common secondary metabolites were flavonoids, cited in 32.26% studies (n = 10). Essential criteria to in vivo animal studies were frequently underreported, suggesting publication bias. The animals treated with plant extracts presented positive results in the osteoblastic proliferation, and consequently, this treatment accelerated osteogenic differentiation and bone callus formation, as well as bone fracture repair. Possibly, these results are associated with antioxidant, regenerative, and anti-inflammatory power of the extracts. The absence or incomplete characterization of the animal models, treatment protocols, and phytochemical and toxicity analyses impairs the internal validity of the evidence, making it difficult to determine the effectiveness and safety of plant-derived products in bone repair.

Does antibiotic use accelerate or retard cutaneous repair? A systematic review in animal models.

BACKGROUND: The presence of infections is one of the main factors that leads to delays in healing or non-closure of cutaneous wounds. Although the goal of antibiotic use is to treat or prevent infection, there is currently no agreement on the effectiveness of these products. AIM: The aim of this study was to evaluate the efficacy of antibiotic use during the healing process of skin wounds in animal models not intentionally infected, as well as to analyze the advances and limitations of the studies carried out in this field. MAIN METHODS: This systematic review was performed according to the PRISMA guidelines, using a structured search on the MedLine (PubMed) and Scopus platforms to retrieve studies published until August 29, 2018, 13:35p.m. The studies included were limited to those that used excision or incision wound models and that were not intentionally infected. The data for the animal models, antibiotic used, and the main results of the studies were extracted, and compared where possible. Bias analysis and methodological quality assessments were examined through the SYRCLE's Risk of Bias tool. KEY FINDINGS: Twenty-seven studies were selected. Overall, the effects of the antibiotic on the wound decreased inflammatory cell infiltration and promoted an increased number of fibroblasts, extracellular matrix constituents, re-epithelialization and tissue strength. A great deal of important information about the methodology was not presented, such as: the statistical analysis used, the animal model (sex and age), antibiotic dosage, blinding and randomization of the animals chosen. SIGNIFICANCE: Based on the results found, we believe that antibiotic therapy can be considered a viable alternative for the treatment of cutaneous wounds. However, current evidence obtained from the methodological quality analysis points towards a high risk of bias. This is due to the incomplete characterization of the experimental design and treatment protocol, which compromises the reproducibility of the studies.

Strychnos pseudoquina modulates the morphological reorganization of the scar tissue of second intention cutaneous wounds in rats.

Natural substances are used in folk medicines to treat injuries. Strychnos pseudoquina has scarring, antipyretic, and antimalarial actions. The present study aimed to analyze the effect of S. pseudoquina on cutaneous wound healing in rats. The S. pseudoquina extract was submitted to phytochemical prospection. The levels of flavonoids and total phenolic compounds in the extract were 50.7 mg/g and 2.59 mg/g, respectively. Thirty Wistar rats were individualized in cages with food and water ad libitum (registration no. 730/2014). After anesthesia, three circular wounds (12mm diameter) were made in the animals, which were randomly separated into five treatments: Sal, saline; VO, ointment vehicles (lanolin and Vaseline); SS, positive control (silver sulfadiazine 1%); LE 5, freeze-dried extract 5%; and LE 10, lyophilized extract 10%. The animals were treated with the ointment daily for 21 days. Every seven days, the area and the rate of wound contraction were evaluated. Tissue samples were removed for histopathological analysis of the number of mast cells, elastic and collagen fibers, and biochemical analyses, quantification of malondialdehyde (MDA), carbonylated proteins (PCN), superoxide dismutase (SOD), catalase (CAT), transforming growth factor ß (TGF-ß), Interleukin 10 (IL-10) and tumor necrosis factor (TNF). The number of mast cells, collagen and elastic fibers in the rat wounds were higher in the treatments with the plant. The extract also stimulated the activity of antioxidant enzymes, particularly SOD, presenting high levels, and maintained low levels of PCN. The TGF-ß and IL-10 concentration was higher in the LE5 and LE10 treatment of the extract than in the Sal, OV and SS treatments on day 7. The ointment based on S. pseudoquina closed the wound faster and accelerated wound healing in animals.