Pain Reaction And C-fos Expression In Rat Spinal Cord In Different Exercised Intensity

In recent years, the studies show that there has been a obvious individual difference bothin animals and human bodies. The studies on pain response and its factors with others woulddeepen understanding and strengthen the individual treatment of pain. Recently, ourresearches found that the chemical sensitivity to noxious stimuli were significantly differentfollowing an exercise-induced fatigue.As far as exercise fatigue is concerned, different fatigue situations have differentresponse to noxious stimulation, which helps to deepen the knowing about human bodyfollowing an exercise fatigue. As far as exercise fatigue is concerned, the bodies in differentstates of the same noxious stimuli are different. In the clinical management and treatment ofpain, the state of the body should be considered. Different individual follows different painsensitivity, but its neurobiological mechanisms remain unclear.Objective and Methods:In present experiment, we use rats as the objects to observe pain response in twodifferent sports fatigue model by use of behavioral methods and c-fos immunohistochemistryin the L4 / 5 lumbar enlargement of spinal cord, to further clarify the different sensitivity topain under exercise-induced fatigue and its neurobiological mechanisms.Results:1) Behavioral studies show that rats after different intensity exercises, being injectedwith formalin on their pelmas, formalin induced pain of two kinds of fatigue rats whencompared with the control group have diphasic pain response. By a respective monotheticvariance analysis of three groups of rats’ licking time, carrying the claw time, touch time andthe number of paw single factors, the results showed that the three groups of rats licking time[F (2,21) = 15.88, P < 0.001] lift claw time [F (2,21) = 2.61, P < 0.05], touch time [F (2,21) =5.17, P < 0.05] had a significant difference while the number of paw [F (2, 21) = 3.97, P >0.05] has no significant difference. LSD method test compared between groups, themoderate-intensity exercise group licking time (2.64±1.52), lift the claw (1.99±1.66), touch (14.5±12.04) was significantly lower than the control group (P < 0.05 ). High intensityexercise group and licking time (1.69±1.49), the lift claw (1.71±0.91), touch (14.38±11.58)was significantly lower than the control group (P < 0.05), moderate-intensity exercise andhigh intensity exercise no difference between the groups. No significant difference betweenthe number of paw withdrawal group;2) Rats after exercise of different intensities of formalin-induced c-fos expression inspinal dorsal horn. After the single-factor analysis of variance of three groups of rats’spinalcord dorsal horn cell number, area, average gray scale, optical density and the equivalentcircle diameter, results showed that the three groups of rats’spinal dorsal horn cell number [F(2,30) = 118.21, P < 0.001] and area [F (2,30) = 57.30, P < 0.001], mean gray [F (2,30) =62.27, P < 0.001], optical density [F (2,30) = 71.83, P < 0.001] were significantly different.Equivalent circle diameter [F (2,30) = 2.56, P > 0.05] has no significant difference. With thehelp of LSD method test comparison between groups, the moderate-intensity fatigue group ratspinal cord dorsal horn cell count (18.91±3.65), area (887.73±204.77) and the opticaldensity (0.50±0.02) than the control group were reduced by (P < 0.001), mean gray ofmoderate-intensity exercise group (83.14±2.51) was lower than the control group by (P <0.01), equivalent circle diameter has no significant difference. High-intensity exercise grouprat spinal dorsal horn cell count (16.18±3.09), area (845.91±200.55) and optical density(0.46±0.03) which is less than the control group by (P < 0.001), the mean gray of thehigh-intensity exercise group (71.96±1.67) less than the control group by (P < 0.001),equivalent circle diameter has no significant difference. High intensity exercise group ofspinal cord dorsal horn cells number (16.18±3.09), the optical density (0.46±0.03) waslower than the number of moderate-intensity exercise group cells (18.91±3.65), the opticaldensity (0.50±0.02) by (P < 0.05, P < 0.001), high intensity exercise group mean gray of therat spinal dorsal horn (71.96±1.67) was less than moderate-intensity exercise group by (P <0.01), which has no significant difference in the area and equivalent circle diameter.Conclusions:1) In the formalin-induced chemical inflammatory pain model, pain sensitivity in ratsafter different intensive exercise were significantly different while the sensitivity of thecontrol rats were significantly higher than the different intensity exercised rats, thus to suggestthat the rats which under the state of motion of the different intensity reflects a significantdifference in pain; 2) In the formalin model, rats after spinal cord dorsal horn c-fos expression havedifferent appearences with those rats which have intensity exercise, moreover, in the controlgroup of c-fos expression in spinal dorsal horn of rats with different intensity exercise ratspinal cord dorsal horn c-fos expression are inconsistent, and expression after differentintensity exercise is also inconsistent, which are obvious different.