Repair function of essential oil from Crocodylus Siamensis (Schneider, 1801) on the burn wound healing via up-regulated growth factor expression and anti-inflammatory effect
Authors: You-Xiong Xiong
Qiong-Hua Chen
Xiao-Tian Liu
Hua-Liang Li
Shao-Min Huang
Qing-Xi Chen
Zi-Ran Zhang
Ya-Hui Zheng
Journal: Journal of Ethnopharmacology (2021)
Discipline: PHARMACOLOGY & TOXICOLOGY
Keywords: Anti-inflammation; Burn wound healing; Crocodylus siamensis; Essential oil.
Affiliations: School of Life Sciences, Xiamen University, Xiamen, 361005, China; Fujian Tuolong Industrial Limited Company, Xiamen, 361026, China. Electronic address: ., School of Life Sciences, Xiamen University, Xiamen, 361005, China. Electronic address: ., Centre for Reproductive Medicine, The First Affiliated Hospital of Xiamen, China., Fujian Tuolong Industrial Limited Company, Xiamen, 361026, China., School of Life Sciences, Xiamen University, Xiamen, 361005, China., Centre for Reproductive Medicine, The First Affiliated Hospital of Xiamen, China. Electronic address: .

Abstract:  Ethnopharmacological relevance: Crocodile oil has been used by traditional physicians around the world to treat wound healing and inflammation. However, the scientific rationale and mechanism behind its use in vivo has not been fully researched. Aims of the study: We mainly investigated the mechanism during crocodile oil treatment of up-regulated growth factor expression and anti-inflammatory on burn wound healing in rats. Materials and methods: The moisture and nitric oxide (NO) levels in the skin of rats were analyzed in the first 14 days after burn and the changes of the structure of the skin tissues in the wound healing were studied by hematoxylin-eosin (H.E.) staining within 21 days after scald. The inflammatory factor on burn wound healing in rats was dected by ELISA kits and Q-PCR. the expression of a variety of growth factors (TGF-β1, VEGE-α, EGF) and PCNA in the skin tissue after burns was evaluated using immunohistochemistry. The down-regulated phosphorylation of p38 MAPK in the wound healing was confirmed by Western-blot analysis. In addition, TEM was used to observe the ultrastructure of scalded skin. Results: This study showed that crocodile oil could significantly reduce the protein and mRNA levels of TNF-α, IL-1β and IL-6. And it was found that the phosphorylation of p38 MAPK was down-regulated in the wound healing (p &lt; 0.05). Meanwhile, crocodile oil can promote the expression of a variety of growth factors (TGF-β1, VEGE-α, EGF) and PCNA in the skin tissue after burns, and promote the repair of collagen fibers in the dermis, preventing the production of melanin and maintain the appearance of repaired skin. 

Retracted: No

PubPeer comments:
 Siamese crocodiles are critically endangered animals. The article discusses the use of essential oils prepared from these crocodiles in wound healing research. Under a section titled  value of the data the authors include the following statement:  This data involves all data belong (sic) to School of Life Sciences, Xiamen University, and is used to production and sales of related products about oil from Crocodylus Siamensis for Fujian Tuolong Industrial limited company. The authors have written  The authors declare no conflict of interest under  Declaration of competing interests . However, three of the authors are employed by Fujian Tuolong Industrial limited company; surely this constitutes a relevant conflict of interest? , 
 **The comment 1:**Siamese crocodiles are critically endangered animals. The article discusses the use of essential oils prepared from these crocodiles in wound healing research. **Answer:** Thanks. *Crocodylus siamensis*, *Crocodylus niloticus* and *Crocodylus porosus* are the CITES appendix species, which are not naturally distributed in China.According to the relevant provisions of the wildlife protection law, only the wild populations of the three crocodiles have been approved as national key protected wild animals, while the artificially bred populations have not been approved, which can be cultured and listed for circulation according to law. After the decision of the Standing Committee of the National People s Congress on comprehensively banning illegal wildlife trade, eliminating the bad habit of indiscriminate consumption of wild animals and effectively ensuring the life, health and safety of the people was issued in February 27, 2021, the Fishery Administration of Ministry of Agriculture and Rural Affairs and the State Forestry and grassland administration strengthened communication and coordination, and successively issued species listed in the list of artificial breeding of aquatic wild animals under national key protection and other lists. According to aquatic animal management. *Crocodylus siamensis,** Crocodylus niloticus* and *Crocodylus porosus *have been listed in the above list and shall be managed according to aquatic animals. Their slaughtering, processing, inspection and quarantine shall be carried out in accordance with the relevant requirements of aquatic animals. **The comment 2 **uff1aUnder a section titled  value of the data the authors include the following statement:  This data involves all data belong (sic) to School of Life Sciences, Xiamen University, and is used to production and sales of related products about oil from Crocodylus Siamensis for Fujian Tuolong Industrial limited company. The authors have written  The authors declare no conflict of interest under  Declaration of competing interests . However, three of the authors are employed by Fujian Tuolong Industrial limited company; surely this constitutes a relevant conflict of interest? **Answer:** Fujian Tuolong Industrial limited company and Xiamen University reached a joint research  crocodile biological products cooperation and signed an agreement in 2017. And this work was supported by the School of Life Sciences at Xiamen University and Fujian Tuolong biological products research and development of the collaborative innovation center project (Grant no.XDHT2017004C). Hua-Liang Li performed most experiments, analyzed data. You-Xiong Xiong provide experimental materials and funds. Zi-Ran Zhang performed in ELISA and Q-PCR analysis. ,