The Research Of Skin Protectant Against Jellyfish Sting

Background and Objective:With economic and social development, the opportunity of human's contact with ocean is rapidly increasing. And jellyfish sting, the most common marine injury, was drawing increasingly attention. Jellyfish stings can cause a variety of local skin symptoms, even may result in death. And a series of questions such as biological activities of nematocysts and toxins are still unclear now. So it's of great scientific and practical importance to conduct the research of prevention and treatment against jellyfish stings. Besides traditional safety net and protective cloth, skin protectant against jellyfish has the most developing potential. Nematocysts are the main acting organelles when jellyfish sting happen. The research idea and main purpose of skin protectant is to reduce and even better inhibit nematocyst from discharging. Upon the current theory, metal ions of high concentration in nematocysts are the power source for discharging. Therefore, it may reduce and even inhibit nematocysts from discharging to raise metal ions' concentration around nematocysts. Based on this idea, nematocyst suspension (NS) of Cyanea capillata, a common toxic jellyfish in Southeast China, was used to test the metal ions'ability on inhibiting nematocysts from discharging and releasing toxins in order to determine a formula of skin protectant.Different types of jellyfish's nematocysts have different biological activities. So one formula is difficult to play a full protective effect against all types of jellyfish. Therefore, to establish a simple, easily repeatable jellyfish sting model and carry out research on jellyfish dermatitis treatment are also a complement and support to the study of skin protectant. Jellyfish sting model was made using rabbits, NS and nematocyst venom (NV). Via mouse foot swelling model and rabbit model,3 kinds of H1 antihistamines and heat treatment are studied.Method:The first part:NS was made from low-temperature frozen tentacles and 4℃artificial seawater (ASW) by self-dissolving and filtration. Different types and concentrations of metal ions' solutions were mixed with NS. After water bath, nematocysts discharge rate (NDR) was counted through ordinary optical microscope.500 mmol/L sodium citrate, ASW and 4℃ASW were used as the positive control, negative control and blank control, respectively.Different types and concentrations of metal ions' solutions were mixed with NS. After water bath and centrifugation, supernatant's protein concentration was measured. Positive control, negative control and blank control were chose as above. Metal ion solutions with strong inhibiting abilities were selected out and tested further.The second part:Rabbits'back hair was removed. NS and NV were used in two ways (grind skin and wipe agents, intradermal injection) to cause skin injury. ASW was used as the blank control. Redness and edema were observed and scored at 1 d,2 d and 3 d after treatment. And the inflammatory lesions were cut to observe pathological changes.Mice were given loratadine, mizolastine, cetirizine hydrochloride and physiological saline 3 days. Thickness of right hind foot palm was measured after the last administration.2 h after last administration,0.02 ml NV was injected into the palm.0.5 h after injection, palm thickness was measured every 0.5 h for 6 h.Rabbit back hair was removed.0.1 ml NV (2.64 mg/ml) was intradermal injected. Then the treatment groups were given loratadine, hot compress or their joint. Positive control group was given physiological saline. Inflammatory lesions'diameter was measured at 1,2,3 and 14 day. In the end, the rabbits were killed and the inflammatory lesions were cut to observe pathological changes.Results and conclusion:The first part:Frozen may have certain impact on nematocysts'biological activities. But NS made from frozen tentacles could be used to replace fresh tentacles for testing nematocysts' biological activities. Different types and concentrations of metal ions'solutions could inhibit nematocysts from discharging and releasing venom. Through the combination and optimization, we determined (500 mmol/L LaCl3+25 mmol/L MgCl2+25 mmol/L CaCl2) is the formula to be used for skin protectant.The second part:Intradermal injecting NS or NV could simulate symptoms and pathological changes after jellyfish sting. NS and NV can replace fresh tentacles to be used for making jellyfish sting model. Loratadine, cetirizine hydrochloride and mizolastine can ease mice's palm swelling caused by NV. And there is no significant difference between the three medicines. Oral administration of loratadine has a good therapeutic effect on Cyanea capillata dermatitis, and hot compress should not be used simultaneously.