the present inventor began his study of spinal cord injuries with an investigation of the mechanism to explain the effectiveness of dexamethasone , which was formerly used for the treatment . the studies of the present inventor have determined that dexamethasone concentrations of 0 . 5 - 4 . 0 micrograms / millilitter increase the solubility of oxygen in plasma by about 40 % ( fig1 ). each of these therapeutic modalities then has the effect of providing a relative increase of available oxygen at the level of the capillary endothelial cell . this net increase in oxygen at this level may be a means of providing free radical scavenging and / or in maintaining mitochondrical function . the water soluble carotenoids have been shown to produce an increase in the diffusion speed ( diffusivity ) of oxygen through plasma of approximately 80 %. ( u . s . pat . nos . of 3 , 788 , 468 and 3 , 853 , 993 ) when dissolved in plasma , the compounds cause an increase in diffusivity of oxygen , carbon dioxide , and various other compounds . since utilization of these compounds should produce a net increase in available oxygen at the capillary endothelial level , it seemed that it might have some efficacy in the therapy of spinal cord injury . this theory was tested and determined to be correct by empirical investigation . the carotenoids useful for this purpose are those of the form : ## str1 ## wherein each r may represent a hydrophilic group and each r &# 39 ; represents hydrogen or methyl . suitable hydrophilic groups include the carboxyl groups or the ester groups of the form coor &# 34 ; wherein r &# 39 ; represents a soluble sugar group , such as c 12 h 21 o 10 , an alkanol group , such as -- ch 2 -- oh , -- ch 2 -- ch 2 oh , or -- ch 2 -- ch 2 -- oh , or a carboxy substituted lower alkyl , such as -- ch 2 -- cooh , -- ch 2 -- ch 2 cooh or -- ch 2 -- ch 2 -- ch 2 -- cooh , or each r and r &# 39 ; may represent a lower alkanol group , such as -- ch 2 -- oh , -- ch 2 -- ch 2 -- oh , or -- ch 2 -- ch 2 -- ch 2 -- oh , a hydroxy group , or an amine group of the form -- nh or nr &# 39 ;&# 34 ; wherein r &# 39 ;&# 34 ; is a lower alkyl , lower alkanol or carboxy substituted lower alkyl , or a carboxy substituted lower alkyl , such as -- ch 2 -- ch 2 -- oh , -- ch 2 -- oh or ch 2 -- ch 2 -- ch 2 -- oh . most preferred are crocetin , also known as 8 , 8 &# 39 ; - diapo - 8 , 8 &# 39 ; - carotenedioate , or a salt , such as the sodium salt , of crocetin . the water soluble carotenoids have been found to be effective in the treatment of spinal cord injuries when applied either by injection intramuscularly , or intravenously into the animal . they could also be given orally . the carotenoid can be injected into the patient , and in an injectable form , it may be combined with vitamins , choline , glycerophosphoric acid , glycol , glycerine or gum tragacanth , etc . the animal or human is treated with from 0 . 001 to 1000 mg of active ingredient per kg of body weight each application , for a total weekly dose rate of 0 . 001 to 1000 mg of active ingredient per kg of body weight / day , and preferably , from 0 . 005 to 500 mg / kg / day or 0 . 001 to 1000 mg / kg / week . the effectiveness of the water soluble carotenoids has been indicated by tests with mongrel dogs , which are standard test animals often used for experimental treatment techniques of this disorder . having generally described the invention , a more complete understanding can be obtained by reference to certain specific examples , which are included for purposes of illustration only and are not intended to be limiting unless otherwise specified . mongrel dogs of both sexes weighing 15 - 30 kg . were anesthetized with pentobarbital . the pentobarbital dosage was 30 mg / kg and was given as a single intravenous bolus . the animals were intubated and maintained with a harvard respiration pump on room air . they were placed on the operating table in the prone position , and the mid - back area was prepped and draped as a sterile field . using aseptic technique a total laminectomy of t 9 or t 10 was done . a single level laminectomy was utilized in the large majority of cases . a 20 gm . weight was then dropped on the cord through a cylindrical tube for a distance of 25 cm . the injury was delivered to the cord with the dura intact . the wound was then closed in layers with 3 - 0 silk suture . the animals were maintained in the vivarium for a period of four weeks , and their neurologic function assessed weekly . crocetin was given in a dose of 45 micrograms / kg . intravenously once daily for two days prior to the lesion , 45 micrograms / kg three times daily on the day of surgery and then 45 micrograms / kg . twice daily after the lesion . after the surgery , two - thirds of the dose was given intravenously and one - third intramuscularly . the treatment was continued for twelve days . crocetin was given in a dose of 90 micrograms / kg . twice daily beginning 30 minutes after the lesion , and continuing for twelve days . two - thirds of the dose was given intravenously and one - third intramuscularly . the dogs were assessed at the end of each week and graded by the system proposed by tarlov . the animals were graded weekly using the tarlov classification , i . e ., 0 = no movement of legs ; 1 = minimal leg movements ; 2 = good leg movements ; 3 = able to stand and possibly walk : 4 = able to walk and run with minimal or no deficit . the results are presented in table 1 . table i . __________________________________________________________________________ first week second week third week fourth week__________________________________________________________________________control1 . 0 0 0 02 . 0 1 1 23 . 0 0 0 14 . 0 0 1 25 . 0 0 0 06 . 0 0 1 1pre - treated1 . 2 3 4 42 . 1 2 2 23 . 2 3 3 44 . 2 2 3 35 . 1 1 2 2post - treated1 . 1 2 3 42 . 1 1 2 33 . 1 2 3 34 . 2 3 3 3__________________________________________________________________________ comparison of the control animals with both the pre - treated and post - treated groups gave a significance level of . 05 or better . each week the crocetin treated dogs were significantly improved over the control group . this was true for both pre - treated and post - treated animals . no significant difference was apparent between the pre - treated and post - treated groups . while this represents a small number of animals , it was of sufficient size to be statistically significant in that all comparisons differed at the . 05 level or better . the animals manifested no signs of untoward reactions to the crocetin which was administered . they did have the usual problems associated with spinal cord injury of urinary retention and decubitus ulcerations . there is some evidence that the early pathophysiologic change which occurs in a traumatized but intact spinal cord is that of local ischemia . this occurs in the first few hours and results in secondary necrosis which is irreversible . in this study it was attempted to determine if an increase in the rate of plasma oxygen diffusion would have any effect in counteracting this hypoxia , and reduce the secondary necrosis of neural tissue . the results of this study were very encouraging , and indicate that this may be a new avenue of approach to the treatment of spinal cord injury . the primary effect of the water - soluble carotenoids is to increase the diffusivity of oxygen through the plasma . in all probability it increases the diffusivity of other compounds in plasma too , and may hasten the removal of lactic acid , for example . the combination of intravenous and intramuscular dosage seem to produce a diffusivity increase lasting several hours . one of the dogs tested was pregnant and her puppies showed no evidence of congenital abnormalities . having now fully described the invention , it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein .
a method for the treatment of spinal cord injuries in a mammal which comprises administering to said stricken mammal an effective dose of a water soluble carotenoid , or prophylactically treating a mammal which is expected to undergo spinal cord injury , such as prior to surgical procedures in the vicinity or on the spinal cord , which comprises administering to said mammal an effective dose of a water soluble carotenoid .