Acute Hyperbaric Oxygenation, Contrary to Intermittent Hyperbaric Oxygenation, Adversely Affects Vasorelaxation in Healthy Sprague-Dawley Rats due to Increased Oxidative Stress

<div>SNP-induced relaxation (SNPIR) of isolated rat aorta rings in the CTRL, A-HBO<sub>2</sub>, 24H-HBO<sub>2</sub>, and 4D-HBO<sub>2</sub> groups. There was no difference in SNPIR among experimental groups of rats. Data were compared by two-way ANOVA and Bonferroni post hoc tests. The CTRL group exhibited lower sensitivity to SNP compared to the A-HBO<sub>2</sub> and 24H-HBO<sub>2</sub> groups of rats (<svg height="15.2035pt" id="M10" style="vertical-align:-3.429399pt" version="1.1" viewbox="-0.0498162 -11.7741 49.6552 15.2035" width="49.6552pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.0091,0,0,-0.0091,0,-5.741)"><path d="M278 -108C276 -72 276 -41 276 6C276 132 289 239 307 279C282 327 275 360 273 404C334 402 369 393 402 372C420 379 445 401 457 422C445 442 420 464 402 471C369 449 334 441 273 439C276 506 281 532 311 583C297 609 275 635 252 647C231 635 207 609 194 583C223 532 229 506 232 439C171 442 135 450 103 471C84 463 60 441 49 422C60 401 84 379 103 372C135 393 171 402 232 404C230 360 224 327 199 279C217 239 228 132 228 6C229 -41 229 -72 227 -108H278Z" id="g50-15"></path></g><g transform="matrix(.013,0,0,-0.013,5.129,0)"><path d="M570 304C570 398 525 448 414 448C385 448 343 445 312 434L329 511L321 518C297 504 262 482 244 460L233 411C195 397 159 381 128 358L135 332C160 347 189 360 224 373L111 -147C97 -210 84 -218 17 -231L13 -257L254 -247L259 -218L233 -216C183 -212 177 -202 189 -142L218 -1C238 -10 266 -12 283 -12C351 3 429 48 483 105C543 168 570 242 570 304ZM482 289C482 161 380 33 304 33C278 33 248 51 233 69L303 396C326 400 352 403 369 403C428 403 482 380 482 289Z" id="g113-113"></path></g><g transform="matrix(.013,0,0,-0.013,16.471,0)"><path d="M512 -3V55L134 254V256L512 456V514L75 281V230L512 -3Z" id="g117-91"></path></g><g transform="matrix(.013,0,0,-0.013,27.734,0)"><path d="M241 635C89 635 35 457 35 312C35 153 89 -12 240 -12C390 -12 443 166 443 312C443 466 390 635 241 635ZM238 602C329 602 354 454 354 312C354 172 330 22 240 22C152 22 124 173 124 313S148 602 238 602Z" id="g113-49"></path></g><g transform="matrix(.013,0,0,-0.013,33.974,0)"><path d="M113 -12C146 -12 170 11 170 46C170 78 146 103 114 103S58 78 58 46C58 11 82 -12 113 -12Z" id="g113-47"></path></g><g transform="matrix(.013,0,0,-0.013,36.938,0)"><path d="M241 635C89 635 35 457 35 312C35 153 89 -12 240 -12C390 -12 443 166 443 312C443 466 390 635 241 635ZM238 602C329 602 354 454 354 312C354 172 330 22 240 22C152 22 124 173 124 313S148 602 238 602Z" id="g113-49"></path></g><g transform="matrix(.013,0,0,-0.013,43.178,0)"><path d="M153 550H386L412 615L406 623H120L82 318C104 327 142 338 184 338C294 338 347 275 347 187C347 112 305 39 221 39C160 39 119 71 97 89C88 97 80 96 71 90C59 80 50 67 49 57C48 45 52 36 66 23C80 9 123 -12 169 -12C221 -11 288 15 342 59C403 109 431 165 431 225C431 308 366 395 238 395C212 395 165 379 127 364L153 550Z" id="g113-54"></path></g></svg>); the 4D-HBO<sub>2</sub> group exhibited lower sensitivity to SNP compared to the 24H-HBO<sub>2</sub> group of rats (<svg height="15.2035pt" id="M11" style="vertical-align:-3.429399pt" version="1.1" viewbox="-0.0498162 -11.7741 49.637 15.2035" width="49.637pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.0091,0,0,-0.0091,0,-5.741)"><path d="M458 122C446 142 422 163 404 170C370 149 335 141 272 139V142C272 216 281 255 311 281C280 309 275 350 272 418C335 417 370 407 404 387C422 394 447 415 458 436C447 456 424 477 402 484C370 463 335 455 272 453C276 506 282 532 312 584C297 610 275 636 253 647C232 636 208 610 194 584C223 532 230 506 234 453C171 455 136 463 102 484C84 477 60 456 48 436C60 415 84 393 102 387C136 407 171 417 234 418C231 350 226 309 195 281C226 255 231 214 234 139C171 141 136 149 102 170C84 163 60 142 48 122C60 101 84 79 102 72C136 93 171 103 234 104C230 35 224 8 195 -42C208 -69 232 -94 254 -106C274 -94 298 -69 312 -42C282 8 276 35 272 104C335 103 370 93 404 72C422 79 446 101 458 122Z" id="g50-16"></path></g><g transform="matrix(.013,0,0,-0.013,5.111,0)"><path d="M570 304C570 398 525 448 414 448C385 448 343 445 312 434L329 511L321 518C297 504 262 482 244 460L233 411C195 397 159 381 128 358L135 332C160 347 189 360 224 373L111 -147C97 -210 84 -218 17 -231L13 -257L254 -247L259 -218L233 -216C183 -212 177 -202 189 -142L218 -1C238 -10 266 -12 283 -12C351 3 429 48 483 105C543 168 570 242 570 304ZM482 289C482 161 380 33 304 33C278 33 248 51 233 69L303 396C326 400 352 403 369 403C428 403 482 380 482 289Z" id="g113-113"></path></g><g transform="matrix(.013,0,0,-0.013,16.453,0)"><path d="M512 -3V55L134 254V256L512 456V514L75 281V230L512 -3Z" id="g117-91"></path></g><g transform="matrix(.013,0,0,-0.013,27.716,0)"><path d="M241 635C89 635 35 457 35 312C35 153 89 -12 240 -12C390 -12 443 166 443 312C443 466 390 635 241 635ZM238 602C329 602 354 454 354 312C354 172 330 22 240 22C152 22 124 173 124 313S148 602 238 602Z" id="g113-49"></path></g><g transform="matrix(.013,0,0,-0.013,33.956,0)"><path d="M113 -12C146 -12 170 11 170 46C170 78 146 103 114 103S58 78 58 46C58 11 82 -12 113 -12Z" id="g113-47"></path></g><g transform="matrix(.013,0,0,-0.013,36.92,0)"><path d="M241 635C89 635 35 457 35 312C35 153 89 -12 240 -12C390 -12 443 166 443 312C443 466 390 635 241 635ZM238 602C329 602 354 454 354 312C354 172 330 22 240 22C152 22 124 173 124 313S148 602 238 602Z" id="g113-49"></path></g><g transform="matrix(.013,0,0,-0.013,43.16,0)"><path d="M153 550H386L412 615L406 623H120L82 318C104 327 142 338 184 338C294 338 347 275 347 187C347 112 305 39 221 39C160 39 119 71 97 89C88 97 80 96 71 90C59 80 50 67 49 57C48 45 52 36 66 23C80 9 123 -12 169 -12C221 -11 288 15 342 59C403 109 431 165 431 225C431 308 366 395 238 395C212 395 165 379 127 364L153 550Z" id="g113-54"></path></g></svg>) (table). Half maximal effective concentration (EC50) presents concentration of SNP (M) which induces a response halfway between the baseline and maximum. LogEC50 values (shown in corresponding tables) were compared by one-way ANOVA test.</div>

Oxidative Medicine and Cellular Longevity

fig6

Figure 6

Figure 6: Acute Hyperbaric Oxygenation, Contrary to Intermittent Hyperbaric Oxygenation, Adversely Affects Vasorelaxation in Healthy Sprague-Dawley Rats due to Increased Oxidative Stress 

Figure 6 | Acute Hyperbaric Oxygenation, Contrary to Intermittent Hyperbaric Oxygenation, Adversely Affects Vasorelaxation in Healthy Sprague-Dawley Rats due to Increased Oxidative Stress 