Study On The Level Of PGE₂ In Masseter Muscle Of The Rats By Unilateral Posterior Teeth Loss

Objective:To analyze the relationship between the content of PGE2 in masseter muscle and time of unilateral posterior teeth loss, and to study the effect unilateral posterior teeth loss to masseter muscle.Methods:Fourty-eight Sprague-Dawley rats were divided into eight groups at random, four experimental groups and four control groups.Each group had six rats,three were males and another three were females.The rats in the experimental groups were extracted the left maxillary and mandibular posterior teeth,then were killed after three days,two weeks,four weeks and twelve weeks.We did nothing to the rats in control groups,and they were killed at the same time corresponding to experimental groups.Radioimmunoassay was used to detect the content of PGE2 in bilateral of masseter muscles.Results:1.The content of PGE2 in bilateral of masseter muscles after extracting three days increases contrast to control group.And it shows statistical significance between experimental group and control group(P<0.01).2.The content of PGE2 in bilateral of masseter muscles after extracting two weeks is lower than three days but still higher than control group(P<0.01).3.The content of PGE2 in bilateral of masseter muscles goes up significantly in postextracting four weeks contrast to postextracting three days(P<0.01).It has statistical significance between the extracting side and non-extracting side(P<0.01). And the content of PGE2 in the extracting side masseter muscle is higher than non-extracting side.4.The content of PGE2 in postextracting twelve weeks decreases contrast to postextracting four weeks(P<0.01). And the extracting side masseter muscle is more deeply affected than non-extracting side.Conclusions:1.Unilateral posterior teeth loss can lead to high level of PGE2 in masseter muscle.All extracting sides masseter muscles are more deeply affected than non-extracting sides except postextracting three days.It is prompted that masseter muscle is affected by unilateral posterior teeth loss,and the extracting side masseter muscle is more serious than non-extracting side.2.The content of PGE2 in masseter muscle increases significantly in postextracting four weeks.The high level in postextracting twelve weeks decreases a little contrast to postextracting four weeks.It may relieve the masseter muscle from damage.This result may relate to masseter muscle's adaptation response and form of new balance.